Additional figures accompany each Supersite writeup.
The Shuttle Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) is a cooperative space shuttle experiment between the National Aeronautics and Space Administration (NASA), the German Space Agency (DARA), and the Italian Space Agency (ASI). The experiment is the next step in NASA's Spaceborne Imaging Radar (SIR) program that began with the Seasat Synthetic Aperture Radar (SAR) in 1978, and continued with SIR-A in 1981 and SIR-B in 1984. The program will eventually lead to TOPSAT, a mission to measure topography globally, and the Earth Observing System (EOS) SAR later in this decade. The program also benefits from the Magellan Mission to Venus, other international spaceborne radar programs (e.g. ERS-1, JERS-1), and prototype aircraft sensors such as the JPL Airborne SAR (AIRSAR).
SIR-C will provide increased capability over Seasat, SIR-A, and SIR-B by acquiring digital images simultaneously at two microwave wavelengths ([[lambda]]): L- band ([[lambda]] = 23.5 cm) and C-band ([[lambda]] = 5.8 cm). These vertically- and horizontally-polarized transmitted waves will be received on two separate channels, so that SIR-C will provide images of the magnitude of radar backscatter for four polarization combinations: HH (Horizontally-transmitted, Horizontally-received), VV (Vertically-transmitted, Vertically-received), HV, and HV; and also data on the relative phase difference between the HH, VV, VH, and HV returns. This allows derivation of the complete scattering matrix of a scene on a pixel by pixel basis. From this scattering matrix, every polarization configuration (linear, circular or elliptical) can be generated during ground processing. The radar polarimetric data will yield more detailed information about the surface geometric structure, vegetation cover, and subsurface discontinuities than image brightness alone (e.g. Elachi et al., 1990; Evans et al., 1986, 1988; Durden et al., 1989; van Zyl et al., 1987; van Zyl, 1989; Zebker and Norikane, 1987).
Germany's imaging radar program started with the Microwave Remote Sensing Experiment (MRSE) flown aboard the Shuttle. This multimode X-band radar was flown on the first SPACELAB mission in 1983. The program was continued by development of the X-SAR, for which cooperation with Italy was initiated. X-SAR, will operate at X-band ([[lambda]] = 3.1 cm) with VV polarization, resulting in a three-frequency capability for the total SIR-C/X-SAR system. Because radar backscatter is most strongly influenced by objects comparable in size to the radar wavelength, this multifrequency capability will provide information about the Earth's surface over a wide range of scales not discernable with previous single-frequency experiments.
This document describes the science investigations that will be conducted with SIR-C/X-SAR. Investigations centered around SIR-C/X-SAR Supersites and Backup Supersites are described in Section IV and V; the investigations of each principal investigator are described in Section V. The SIR-C/X-SAR instrumentation and overall science objectives are described in Sections II and III respectively and provide background for the science investigation descriptions in the later sections.
II. SIR-C/X-SAR INSTRUMENTATION
SIR-C will provide multifrequency, multipolarization radar data. The SIR-C instrument is composed of several subsystems: the antenna array, the exciter, the receivers, the data-handling subsystem, and the ground SAR processer. The antenna is composed of two planar arrays, one for L-band and one for C-band . Each array is composed of a uniform grid of dual-polarized microstrip antenna radiators, with each polarization port fed by a separate corporate feed network. The overall size of the SIR-C antenna is 12.0 x 3.7 meters and consists of three leaves each divided into four subpanels.
Unlike previous SIR missions, the SIR-C radar beam is formed from hundreds of small low power solid state transmitters embedded in the surface of the radar antenna. By properly phasing the energy from these transmitters, the beam can be electronically steered in the range direction +/-23deg. from the nominal 40deg. off nadir position without physically moving the large radar antenna. This feature will enable images to be acquired over a wide range of incidence angles.
X-SAR will provide VV polarizaton images using a passive slotted waveguide antenna measuring 12.0 x 0.4 meters . This antenna will be mechanically deployed once the shuttle has attained a stable earth orbit. Other X-SAR components include a travelling wave tube as transmitter, an exciter, receiver, and data handling subsystem. A mechanical tilt mechanism will point the X-SAR antenna to angles between 15 and 60deg., in alignment with the L-band and C-band beams.
Both SIR-C and X-SAR can be operated as either stand alone radars or in conjunction with each other. Roll and yaw maneuvers of the shuttle will allow data to be acquired on either side of the shuttle nadir track. The width of the ground swath varies from 15 to 90 kilometers (9 to 56 miles) depending on the orientation of the ant enna beams and the operational mode. Table 1 presents a summary of SIR-C/X-SAR system characteristics.
Table 1: SIR-C/X-SAR System Characteristics
PARAMETER L-BAND C-BAND X-BAND
Wavelength 0.235 m 0.058 m 0.031 m
Swath Width 15 to 90 km 15 to 90 km 15 to 40 km
Transmit Pulse Length 33.8, 16.9, 8.5 us 33.8, 16.9, 8.5 us 40 us
Data Rate 90 Mb/s 90 Mb/s 45 Mb/s
Data Format 8,4 b/word 8,4 b/word 4,6 b/word
(8,4) BFPQ (8,4) BFPQ (8,4) BFPQ
PARAMETER SYSTEM
Orbital Altitude 225 km
Resolution 30 x 30 m on the surface
Look Angle Range 17 to 63 degrees from nadir
Bandwidth 10 and 20 MHz
Pulse Repetition Rate 1395 to 1736 pulses per second
Total Science Data 50 hours/channel/mission
Total Instrument Mass 11,000 kg
DC Power Consumption 3000 to 9000 W
III. SIR-C/X-SAR SCIENCE OBJECTIVES
The sensitivity of imaging radar to surface and, in some cases, subsurface geometry, and electrical properties can provide information about land and ocean surfaces and vegetation cover that is unique or complementary to measurements made by sensors operating in the visible, near infrared, and thermal infrared portions of the electromagnetic spectrum. SAR provides its own illumination and can therefore produce reliable multitemporal data independent of weather or solar illumination, through all seasons, and at any latitude. It should be noted that 3-dimensional features are enhanced, in comparison with optical imaging sensors, due to the side-looking illumination and imaging geometry. Radar waves penetrate clouds and, under certain conditions, vegetation canopies, ice, and dry alluvial or aeolian soil, making it possible to explore near-surface zones that are not accessible with other remote sensing techniques. SIR-C/X-SAR will form a joint payload with MAPS (Measuring Air Pollution from Space) as part of the Space Radar Laboratory (SRL) mission. Therefore, the SRL mission will provide measurements of both the earth's surface and the earth's atmosphere.
The SIR-C/X-SAR mission extends the capability of an aircraft campaign by providing regional scale data on a rapid temporal scale. The mission design also enables areas to be imaged at multiple aspect and incidence angles, important parameters for studying many land and ocean processes. The extensive surface measurement campaigns will provide critical data to be used in development of algorithms needed to produce key geophysical products for assessing global change issues. By having multiple flights, insights on seasonal variations for the key science issues will also be provided. Such validation and algorithm development studies will be critical for developing the EOS SAR requirements and mission design.
The SIR-C/X-SAR Science Team, made up of 49 team members and 3 team associates (Table 2), was selected in 1988. The Science Team has selected over 400 sites (Table 3) as possible targets for the SIR-C/X-SAR radar. Although each SIR-C/X-SAR team member was selected to carry out a specific scientific investigation, several central themes have emerged for the overall SIR-C/X-SAR mission. These research topics include the global carbon cycle; the hydrologic cycle; paleoclimate and geologic processes; ocean circulation and air-sea interactions; and advanced technology. To address these research areas, the concept of Supersites, at which data acquisition will be focused, has been developed.
References
Durden, S. L., J. J. van Zyl, and H. A. Zebker (1989) Modeling and observations of the radar polarization signatures of forested areas, IEEE Trans. Geosci. and Rem. Sens., Vol. GE-27, pp. 290-301.
Elachi, C., Y. Kuga, K. C. McDonald, K. Sarabandi, T. B. A. Senior, F. T. Ulaby, J. J. van Zyl, M. W. Whitt, and H. A. Zebker (1990) Radar polarimetry for geoscience applications, F. T. Ulaby and C. Elachi editors, Artech House, Inc.
Evans, D. L., T. G. Farr, J. J. van Zyl, and H. A. Zebker (1986) Multipolarization radar images for geologic mapping and vegetation discrimination, IEEE Trans. Geosci. Rem. Sens., Vol. GE-24, pp. 246-257.
Evans, D. L., T. G. Farr, J. J. van Zyl, H. A. Zebker (1988) Radar Polarimetry: Analysis Tools and Applications, IEEE Transactions on Geoscience and Remote Sensing, vol. 26, no. 6, 774-789.
Huneycutt, B. L. (1993) Spaceborne Imaging Radar-C Instrument, Proceedings of the Third Spaceborne Imaging Radar Symposium, January 18-21, 1993. pp. 61-65.
Shuttle Imaging Radar-C Science Plan, September 1, 1986, Jet Propulsion Laboratory Publication 86-29, Pasadena, California.
van Zyl, J. J., H. A. Zebker, and C. Elachi (1987) Imaging radar polarization signatures: Theory and observation, Radio Science, Vol. 22, pp. 529-543.
van Zyl, J.J. (1989) Unsupervised classification of scattering behavior using radar polarimetry data, IEEE Trans. on Geosci. and Rem. Sens., 27, 1, 36-45.
Way, J. and E. A. Smith (1991) The Evolution of Synthetic Aperture Radar Systems and their Progression to the EOS SAR, IEEE Trans. on Geosci. and Rem. Sens., 29, 6, 962-985.
Werner, M. U. (1993) The X-band Synthetic Aperture Radar on-board the Space Shuttle, Proceedings of the Third Spaceborne Imaging Radar Symposium, January 18-21, 1993, pp. 67-73.
Zebker, H. A. and L. Norikane (1987) Radar polarimeter measures orientation of calibration corner reflectors, Proceedings of the IEEE, Vol. 75, pp. 1686-1688.
Table 2: SIR-C/X-SAR Science Team
Investigator Affiliation Investigation
W. Alpers University of Hamburg, Germany Ocean Wave Spectra
R. Beal Applied Physics Lab, USA Ocean Wave Transport
R. Brown Canada Center for Remote Sensing, Canada Vegetation Charac.
P. Canuti CETEM, Italy Estimates of Soil Erosion
R. Cordey Marconi Research Center, England Agriculture and Forestry
E. Dabbagh King Fahd Univ. of Petrol and Minerals, Saudi Arabia Geology and Hydrology
F. Davis University of California, Santa Barbara, USA Biomass Modeling
J. Dozier University of California, Santa Barbara, USA Snow Properties
E. Engman NASA/Goddard, USA Hydrology
T. Farr Jet Propulsion Laboratory, USA Climate Change
P. Flament University of Hawaii, USA Ocean Fronts
A. Freeman Jet Propulsion Laboratory, USA Calibration
M. Fujita Communications Research Laboratory, Japan Calibration
A. Gillespie University of Washington, USA Alluvial Fan Evolution
R. Goldstein Jet Propulsion Laboratory, USA Interferometry
R. Greeley Arizona State University, USA Aeolian Roughness
H. Guo Inst. for Remote Sensing Applications, China Radar Penetration
F. Heel DLR, Germany Calibration
B. Isacks Cornell University, USA Topography and Climate
A. Jameson Applied Research Corporation, USA Precipitation
E. Kasischke Environmental Institute of Michigan, USA Biomass of Pine Forests
G. Keyte Royal Aerospace Establishment, England Ocean Waves
J. Kong Massachusetts Institute of Technology, USA Polarimetric Mapping
F. Kruse University of Colorado, USA Lithologic Mapping
T. Le Toan Centre d'Etudes Spat. des Rayonnements, France Biomass of Forests
F. Li Jet Propulsion Laboratory, USA Precipitation
F. Lozano-Garcia National University of Mexico, Mexico Rain Forest Dynamics
J. McCauley Northern Arizona University, USA Saharan Drainages
J. Melack University of California, Santa Barbara, USA Tropical River Floodplains
F. Monaldo Applied Physics Laboratory, USA Ocean Wave Spectra
D. Montgomery US Naval Observatory, USA Oceanography
R. Moore University of Kansas, USA Calibration
P. Mouginis-Mark University of Hawaii, USA Basaltic Shield Volcanoes
P. Murino Inst. U. Nobile, Italy Volcanology
J. Paris California State University, Fresno, USA Habitat Change
K. Paw U University of California, Davis, USA Canopy Structure
K. Pope Geo Eco Arc Research, USA Wetland Structure
K. Raney RADARSAT, Canada Ocean Physics
J. Ranson NASA/Goddard, USA Forest Ecosystems
C. Rapley University College, London, England Altimetry
H. Rott University of Innsbruck, Austria Glacier Properties
G. Schaber US Geological Survey, USA Radar Penetration
J. Soares INPE, Brazil Hydrology
R. Stern University of Texas at Dallas, USA Structural Geology
G. Taylor University of New South Wales, Australia Groundwater Management
F. Ulaby University of Michigan, USA Ecosystem Processes
S. Vetrella University of Naples, Italy Calibration
D. Vidal-Madjar CNET/CRPE, France Hydrology
J. Wang NASA/Goddard, USA Hydrology
R. Winter DLR, Germany Forestry
C. Wood University of North Dakota, USA Volcanism & Tectonism
H. Zebker Jet Propulsion Laboratory, USA Polarimetric Modeling.
Table
3: SIR-C/X-SAR Sites[*
]
Explanation of Site IDs
All SIR-C/X-SAR sites have been assigned a three character Site ID. The first
character of the Site ID indicates the primary discipline of the investigations
for that site as follows:
C = Calibration
E = Ecology
G = Geology
H = Hydrology
M = ElectroMagnetic Theory
N = Oceanography
T = Targets of Opportunity
The second character of the Site ID is used to designate if the site is a
Supersite, Backup Supersite, or Non-Supersite as follows:
S = Supersite
B = Backup Supersite
any other character = Non-Supersite
The third character of the Site ID is simply used for additional
identification.
IV. SIR-C/X-SAR SUPERSITES
Site ID Site Name Latitude Longitude PI Name
Calibration Sites
C01 Akita (1), Japan 39.7 140.083 Fujita
C02 Alberta, Canada 54.00 -115.00 Jameson
C03 Alice Springs Australia -23.50 134.00 Rapley
C04 Amazon C, Brazil 0.00 -70.00 Moore
C05 Bari, Italy 41.07 16.52 Vetrella
C06 Beam Alignment 0.00 0.00 Freeman
C07 Cape Canaveral 28.00 -80.50 Li
C08 Darwin, Australia -12.28 130.50 Jameson
C09 DSN 43, Australia -35.404 148.98 Freeman
C10 DSN 14, Goldstone 35.426 -116.889 Goldstein
C11 DSN 63, Spain 40.432 -4.247 Freeman
C12 Izuoshima Island (1), Japan 34.717 139.4 Fujita
C13 Kashima (3), Japan 35.95 140.667 Fujita
C14 Kauai, HI 22.00 -159.30 Jameson
C15 Kennedy Space Center 28.24 -80.36 Jameson
C16 Kwajalein 8.75 168.00 Jameson
C17 Mt. Fugendake, Japan 32.75 130.15 Fujita
C18 Mt. Fuji (2), Japan 35.367 138.733 Fujita
C19 N. Death Valley, CA/NV 36.85 -116.975 Freeman
C20-C24 NW Simpson A0-A4, Australia -24.25 136.50 Rapley
C25 Ohgata-Mura (1), Japan 40.00 140.00 Fujita
C26 Phuket, Thailand 8.00 98.30 Jameson
C27 Rogers Lake, CA 34.946 -117.835 Freeman
C28 Rutherford-Appleton Labs 51.20 -0.40 Jameson
C29 Soda Lake, CA 35.083 -116.083 Freeman
C30 Thailand 15.75 101.00 Jameson
C31 Tsukuba (2), Japan 36.03 140.10 Fujita
C32 Wallops Island 37.87 -75.38 Jameson
CB1 Matera, Italy 40.66 16.62 BSMatera
CB2 Sarobetsu, Japan 45.117 141.70 BSJapan
CB3 Palm Valley, Australia -23.954 132.712 BSPalm
CBA-CBI Eastern Pacific 1-9 22.50 -115.00 BSEPac
CS1 Flevoland, Netherlands 52.27 5.35 SSFlev
CS2 Kerang, Australia -36.042 144.042 SSKerang
CS3 Oberpfaffenhofen, Germany 48.08 11.28 SSOber
CS4 Western Pacific 27 -15.00 155.00 SSWPac
CS5 Western Pacific 28 -15.00 165.00 SSWPac
CSA-CSZ Western Pacific 1-26 15.00 105.00 SSWPac
CXD Equatorial Pacific Survey -30.371 -166.686
CXH Amazon Calibration -6.407 -61.396
Ecology
Sites
E02 Altamaha, Georgia 31.025 -81.85 Melack
E05 Amazon Forest, Brazil -2.40 -59.80 Paris
E06 Nelson House, Manitoba 55.183 -101.685 BOREAS
E07 Apalachicola, Florida 30.00 -85.00 Melack
E13 Chimalapas, Mexico 17.208 -94.00 Lozano-Garci
a
E14 Borden, Canada 44.317 -80.933 Paw U
E15 Kalakmul, Yucatan 18.28 -89.75 Lozano-Garci
a
E17 Darwin, Australia -12.45 132.565 Taylor
E18 Davis, California 38.367 -121.767 Paw U
E19 Etosha National Park, Namibia -18.50 15.50 MAPS Site
E20 Freiburg, Germany 48.20 7.667 Winter
E21 Gujarat, India 22.00 72.00 Winter
E22 Gippsland, Australia -37.80 147.20 Taylor
E23 Kruger National Park, South -23.625 31.50 MAPS Site
Africa
E24 Haryana, India 29.50 76.50 Winter
E25 Harz, Germany 51.80 10.58 Winter
E27 Kehlheim, Germany 48.90 11.833 Winter
E29 Kourou, Fr. Guyana 5.25 -52.75 Le Toan
E30 La Victoria, Mexico 14.82 -92.50 Pope
E31 Landes, France 44.50 -0.665 Le Toan
E32 Luquillo, Puerto Rico 18.292 -65.808 Paris
E33 Mabira, Uganda 0.475 32.779 Paris
E34 Mack Lake, Michigan 44.583 -83.917 Ulaby/Dobson
E36 Montes Azules, Yucatan 16.47 -91.125 Lozano-Garci
a
E39 Okefenokee, Georgia 30.75 -82.25 Melack
E40 Orono, Maine 45.20 -68.742 PawU
E41 Ouango, West Africa 18.00 -2.70 Le Toan
E42 Araracuara, Columbia -0.41 -72.04 Le Toan
E43 Mabura Hill, Guyana -5.08 -58.41 Le Toan
E44 Guaviare, Colombia 2.28 -72.36 Le Toan
E46 Oxford County, Ontario 42.80 -80.70 Brown
E48 Paracou, Fr.Guyana 5.25 -52.917 Le Toan
E49 Pellston, Michigan 45.533 -84.717 Ulaby/Dobson
E50 Pines Line, US 33.45 -86.82 Kasischke
E51 Pooncarri, Australia -33.54 143.05 Taylor
E55 Rio Hondo, Belize 18.14 -88.67 Pope
E57 Salsipuedes, Yucatan 21.47 -87.07 Pope
E58 Chulchaca, Yucatan 20.86 -90.20 Pope
E61 Shasta, California 41.333 -122.00 Davis
E63 Ste. Elie, Fr. Guyana 5.267 -53.166 Le Toan
E65 Superior, Minnesota 48.10 -92.00 Ranson
E66 Thetford, England 52.48 0.57 Cordey
E67 Voyageurs, Minnesota 48.33 -92.83 Ranson
E69 Weipa, Australia -12.925 141.75 Taylor
E77 Whitecourt, Canada 54.50 -115.667 Brown
E78 Southeast, U.S. 34.00 -83.844 Kasischke
E79 Ouango-Look, West Africa 7.50 11.00 Le Toan
EB1 Howland, Maine 45.20 -68.75 BSHow
EB2 Altona, Manitoba 49.10 -97.60 BSAltona
EB3 Prince Albert, Saskatchewan 54.783 -103.338 BSPrin
EB4 Pantanal, Brazil -18.85 -57.00 BSAmazSurv
EB5 Sena Madureira, Brazil -9.00 -68.40 BSAmazSurv
ES0 Manaus Anavilhanas, Brazil -2.72 -60.75 SSManA
ES1 Manaus Cabaliana, Brazil -3.33 -61.00 SSManC
ES2 Manaus CSAP, Brazil -2.40 -59.80 SSManS
ES5 Duke Forest, North Carolina 36.00 -79.00 SSDuke
ES6 Raco, Michigan 46.392 -84.885 SSRaco
EX1-EXD Sahel 11.485 -7.525 Le Toan
EXL-EXS Siberia 55.243 65.044
EXZ Amazon Vegetation -10.698 -57.966 Melack
Geology
Sites
G01 Aksayqin Basin, China 34.75 80.00 Farr
G02 Amboy, CA 34.525 -115.80 Greeley
G03 Big'at Sayyarim, Israel (2) 29.845 34.86 Greeley
G04 Bighorn Basin, Wyoming 44.40 -108.25 Kruse
G05 C. Italy/S. Germany 45.50 11.50 Murino
G06 Campania, Italy 40.50 13.75 Murino
G07 Canon City/Cripple Crk, CO 38.50 -105.25 Kruse
G08 Kliuchevskoi, Kamchatka 56.18 160.78 Mouginis-Mar
k
G09 Confidence Mill Playa, CA (1) 35.84 -116.555 Greeley
G0B Holot Haluza, Israel 31.20 34.42 Greeley
G0C Sebkra Merkerrhane, Algeria 26.00 1.50 McCauley
GOD-GOG Namib 1-4, So. Africa -23.00 14.70 Schaber
G0H Quito, Ecuador -0.25 -77.75 Isacks
G0I Chulcanas, Ecudaor -5.00 -79.25 Isacks
G0J Santa Rosa, Peru -14.50 -70.40 Isacks
G0K Charana, Bolivia -17.25 -69.00 Isacks
G0L Salar de Uyni, Bolivia -21.00 -68.00 Isacks
G0M Cerro del Taro, Chile -29.00 -70.00 Isacks
G0N Cerro Aconcagua, Argentina -32.00 -70.00 Isacks
G0O Los Andes, Chile -32.25 -70.50 Isacks
G0P Esquel, Argentina -43.00 -72.00 Isacks
G0Q Holot Agur, Israel 31.02 34.41 Greeley
G0R Yuma, Arizona 32.485 -114.431 Schaber
G0S Moenkopi, Arizona 35.822 -111.264 Schaber
GOT-GOV Hotien East Map 1-3 37.952 83.461 Farr
G0W Kuqa, northwest China 41.70 83.00 Farr
G0X Saudi Arabia D (1) 4 16.00 46.50 BSSaudi
G0Y Endere 37.867 84.00 Farr
G10 Cooper Creek, Australia -27.25 142.00 Taylor
G11 Cotopaxi, Ecuador -0.65 -78.43 Wood
G12 Death Valley (2), CA 36.222 -117.278 Gillespie
G13 Dumont Sandsheet (2) 35.65 -116.295 Greeley
G14 Dun Huang, China 39.00 94.50 Farr
G15 Fish Lake Valley, NV (2) 37.739 -118.056 Gillespie
G16 Foulum, Denmark (1) 56.515 9.65 Greeley
G17 Fowler's Gap (1), Australia -31.08 141.67 Taylor
G18 Gobabeb, Namib (2) -23.503 15.15 Greeley
G19 Golden Canyon Fan (1) 36.395 -116.845 Greeley
G20 Ha Meshar, Israel (2) 30.43 34.94 Greeley
G21 Hotien Northwest, China 37.25 78.667 Farr
G22 Iglesiente-Sardinia (1) 39.325 8.517 Murino
G23 Indian Subcontinent 28.50 72.75 Schaber
G24 Jornada, SW US/Mex 32.664 -106.771 Schaber
G25 SW Kalahari -25.50 21.75 Schaber
G26 Karakax Valley, China 36.292 78.75 Farr
G27 Kit Fox Fan (1), CA 36.66 -117.045 Greeley
G28 Kuwait (3) 29.50 47.17 Greeley
G29 Kyle Cyn/Sheep Range, NV (2) 36.556 -115.528 Gillespie
G30 Lago Albano (1) 41.74 12.66 Murino
G31 Lake Eyre, Australia -28.00 136.50 Taylor
G32 Lucerne Dry Lake (1) 34.516 -116.96 Greeley
G33 Lunar Lake Playa (1) 38.40 -116.00 Greeley
G34 Tolbachik, Kamchatka 55.93 160.47 Mouginis-Mar
k
G35 Mishor Paran, Israel (2) 30.07 34.775 Greeley
G36 Namib, So. Africa (ctr pt) -23.50 15.20 Schaber
G37 Navajo Res, SW US/Mex 36.00 -111.00 Schaber
G38 Northern Andes 0.85 -77.475 Wood
G39 Northern Andes Arc 0.75 -77.325 Wood
G40 Bezymianny, Kamchatka 56.07 160.72 Mouginis-Mar
k
G41 Owens Valley, CA (1) 36.792 -118.142 Gillespie
G42 Pisgah, CA 34.73 -116.40 Greeley
G43 Reunion Island -21.145 55.43 Mouginis-Mar
k
G44 Ruiz, Colombia 4.88 -75.37 Wood
G45 Salt Wells Flats (1) 36.05 -116.845 Greeley
G46 Salton Sea (2) 33.215 -115.855 Greeley
G47 Silurian Lake (1) 35.35 -116.175 Greeley
G48 Silver Lake (1) 35.335 -116.13 Greeley
G49 Sonora, Mexico 29.75 -109.75 Kruse
G50 Sonoran Des, SW US/Mex 32.50 -113.50 Schaber
G51 Sudan (2) 20.00 35.00 Stern
G52-G56 Sudan A0-A4 20.00 34.50 Stern
G57 Sudan, Kabous Ophiolite (4) 11.667 31.25 Stern
G58 Sudan, Nakasib Suture (3) 19.667 36.667 Stern
G59 Sudan, Wadi Halfa (5) 21.50 31.00 Stern
G60 Trail Canyon Fan, CA (1) 36.31 -116.905 Greeley
G61 Tsondab Flats, Namib (2) -23.805 15.085 Greeley
G62 Karymsky, Kamchatka 54.07 159.60 Mouginis-Mar
k
G63 Fort Flatters, Sahara 23.00 2.50 Schaber
G64 Aouelloul, Mauritania (N 20.25 -12.68 Greeley
Africa)
G65 Stauning, Denmark (1) 55.935 8.43 Greeley
G66 Biq'at Mahmal, Israel 30.655 34.935 Greeley
G67 Holot Shunera, Israel 30.95 34.605 Greeley
G68 Roter Kamm, Namibia (S Africa) -27.765 16.30 Greeley
G69 Temimichat-Ghallaman, 24.25 -9.65 Greeley
Mauritania
G70 Tenoumer, Mauritania (N 22.92 -10.40 Greeley
Africa)
G71 Wolf Creek, Australia -19.30 127.77 Greeley
G72 Vesuvio, Italy 40.82 14.42 Murino
G73 Phlaegrean Fields, Italy 40.83 14.17 Murino
G74 Eastern Desert of Egypt 25.5 33.65 Murino
G75 N Grapevine Mtns 1, CA 37.20 -117.46 Kruse
G76 Cuprite, NV 37.54 -117.18 Kruse
G77 N Grapevine Mtns 2, CA 37.10 -117.46 Kruse
G78 Ubehebe Crater, CA 37.00 -117.46 Kruse
G79 Grapevine Mtns, CA 36.75 -117.00 Kruse
G80 Tucki Mtns/Fan, CA 36.50 -117.75 Kruse
G81 Black Mtns, CA 36.25 -117.75 Kruse
G82 Altai, China 46.00 90.50 Guo
G83 Hainan, China 19.00 109.50 Guo
G84 Alashan, China 40.00 105.00 Guo
G85 Beijing, China 40.50 116.50 Guo
G86 Changzhou, China 32.00 120.00 Guo
G87 Alishan, China 23.50 121.00 Guo
G88 Condobolin, Australia -32.90 146.70 Taylor
G89 El Oued, Sahara 34.705 8.50 Schaber
G90 Melrhir, Algeria 34.66 6.26 Schaber
G91 Monastir, Tunisia 35.60 10.64 Schaber
G92 Kharga, Sahara 19.313 25.521 McCauley
G93 Wadi Tafassasset, Central 20.875 9.96 McCauley
Sahara
G94 Tafassasset/Azouak 16.333 3.875 Schaber
G97 Dandan-Uilik 37.60 80.733 Farr
G98 Pinatubo, Philippines 15.14 120.35 Mouginis-Mar
k
G99 Turkmenistan, China 38.30 61.20 Farr
GB0 Hawaii 19.35 -155.33 BSHawa
GB1 Hotien East, China 36.833 80.75 BSHot
GBZ, GB2-GB5 Saudi Arabia C (2) 0-4 25.75 43.333 BSSaudi
GB6-GB9 Saudi Arabia D (1) 0-3 20.55 48.271 BSSaudi
GBA-GBE Saudi Arabia A (1) 0-4 23.521 51.208 BSSaudi
GBF-GBJ Saudi Arabia A (2) 0-4 28.917 39.938 BSSaudi
GBK-GBO Saudi Arabia B (1) 0-4 19.083 47.958 BSSaudi
GBP-GBT Saudi Arabia B (2) 0-4 21.521 57.00 BSSaudi
GBU-GBY Saudi Arabia C (1) 0-4 19.708 48.917 BSSaudi
GS1 Galapagos Islands -0.16 -91.27 SSGalap
GS2 Stovepipe Wells Fan, CA 36.645 -117.065 SSDeaV
GS3 Tilemsi, Sahara 20.00 0.00 SSSah
GS4 Fort Zinder, Sahara 20.00 5.00 SSSah
GS5 Lake Chad, Sahara 20.00 10.00 SSSah
GS6 Sahara 4 20.00 15.00 SSSah
GS7 Siwa/Largeau, Sahara 20.00 20.00 SSSah
GS8 Bir Misaha, Sahara 20.00 25.00 SSSah
GS9 Dongola, Sahara 20.00 30.00 SSSah
GSJ Puerto Aisen, Chile -46.00 -73.00 SSAndes
GSK Cerro Cumbrera, Chile -47.50 -73.00 SSAndes
GSL Cerro Laukaru, Chile -48.94 -73.15 SSAndes
Hydrology Sites
H01 Bonn, Germany 50.82 6.85 Canuti
H03 Schorfheide, Germany 53.083 13.733 Canuti
H04 Emerald Lake 36.60 -118.68 Dozier
H05 Fresno California 37.00 -119.50 Wang
H06 Grossglockner (2) 47.10 12.70 Rott
H07 Himalaya 2 32.00 77.50 Canuti
H08 Khumba Himalaya 28.22 86.82 Dozier
H10 Konza (2) 39.083 -96.558 Wang
H11 Near ERS-1 SAR calib site 46.86 -0.62 Vidal-Madjar
H12 Oltrepo' Pavese 45.125 9.35 Canuti
H13 Orgeval Watershed 48.85 3.125 Vidal-Madjar
H14 Salzgitter, Germany 52.425 10.525 Canuti
H15 San Joaquin Ridge 37.62 -119.03 Dozier
H16 Tien Shan 43.00 87.25 Dozier
H17 Uelzen 52.85 10.54 Canuti
H18 Weissfluhjoch 46.83 9.78 Dozier
H19 Zwalm Catchment 50.83 3.76 Engman
HB0 Mahantango A0, Penn. 40.70 -76.58 BSMahn
HB5 Mammoth Mtn 37.50 -119.00 BSMamm
HS1 Bebedouro, Brazil -9.08 -40.28 SSBebe
HS2 Chickasha, OK 34.92 -98.02 SSChick
HS3-HS7 Montespertoli A0-A4, Italy 43.55 11.25 SSMont
HS8 Otztal, Austrian Alps (1) 46.80 10.80 SSOtzl
ElectroMagnetic Theory Sites
M01 Ubar 18.25 53.65 Zebker
MS1 Safsaf, Egypt/Sudan 22.178 29.793 SSSaf
Oceanography Sites
N01 CA/OR Coast 38.00 -124.00 Flament
N02 E Australian Current -32.50 153.00 Raney
N03 English Channel 52.00 2.00 Keyte
N04 Blue Hawaii 20.00 -160.00 Montgomery
N05 Gulf of Genoa 44.30 9.05 Alpers
N06-N10 Gulf of Mexico 0-4 26.75 -87.50 Montgomery
N14 Gulf of St. Lawrence 3 46.75 -71.00 Montgomery
N17-N21 Juan de Fuca Strait A0-A4 48.50 -126.00 Raney
N35-N39 NE Pacific Ocean A0-A4 55.00 -140.00 Montgomery
N41-N42 Netherlands A, B 52.50 4.30 Keyte
N43 Norfolk Is. -29.02 167.57 Montgomery
N44 North Sea East 56.00 8.00 Johannessen
N46 Oslo, Norway 59.50 10.50 Montgomery
N48-N52 Sea of Okhotsk A0-A4 52.50 145.00 Montgomery
N53 Southern Africa -35.00 25.00 Flament
N54 Str of Gibraltar 36.00 -5.60 Alpers
N57 Strait of Sicily 37.125 12.163 Montgomery
N58 Tasman Sea -42.25 144.75 Raney
N60-N64 WN Atlantic 0-4 51.50 -43.50 Monaldo
N65 N. Atlantic 0 55.70 -20.00 Keyte
N66-N70 Japan A0-A4 32.50 135.50 Alpers
N71-N75 Japan B0-B4 44.00 140.00 Alpers
N76-N80 Japan C0-C4 38.00 134.00 Alpers
N81-N85 Japan D0-D4 44.50 143.50 Alpers
N86-N90 Gulf Stream B0-B4 33.00 -77.00 Montgomery
N91-N95 EN Atlantic 0-4 49.50 -15.00 Keyte
NB0-NB8 Equatorial Pacific 0-8 2.50 -140.00 BSEqPac
NBA-NBE North Sea A0-A4 54.75 5.00 BSNoSea
NBF-NBJ Labrador Sea A0-A4 48.50 -52.05 BSLabSea
NS0-NS4 Gulf Stream A0-A4 36.00 -73.00 SSGulf
NS5-NS9 EN Atlantic A-E 47.00 -20.60 SSAtlan
NSA-NSX Southern Ocean 1-24 -58.50 0.00 SSSoOc
NSZ EN Atlantic F 45.40 -21.70 SSAtlan
NX1-NXE Equatorial Pacific Survey 1.488 -112.767
Targets of Opportunity
G95 Chicxulub, Mexico 21.27 -89.6
G96 Phnum Voeene, Cambodia 14.00 106.50
T01 Ak Sipil 37.25 80.167
T04 Karadong 38.617 81.767
T05 Niya 38.00 82.70
T07 Zhamanshin, USSR 48.333 61.00
The SIR-C/X-SAR Science Team has selected nineteen supersites for intensive coverage during the mission. In addition, fifteen backup supersites have been selected for added redundancy should operating parameters change during the mission. Interdisciplinary studies will occur at each Supersite. Table 4 lists the Supersites and Backup Supersites and their locations ; each Supersite and Backup Supersite is discussed in detail in Sections III and IV, respectively.
Nominally, 50 hours of SIR-C/X-SAR data will be recorded onboard the shuttle during each flight. A limited amount of these data will be transmitted to ground receivers for near-real-time digital processing during the mission. Supersites will drive radar parameters and look directions during the mission and will receive priority for survey and standard product processing following the mission.
Supersites from which data will be collected to address the global carbon and hydrologic cycles include tropical forests in the Amazon Basin, boreal forests in northern Michigan, and temperate forests in North Carolina. Supersites in which data will be collected to address the hydrologic cycle include areas of Brazil, Italy, and the midwestern United States. Paleoclimate and geologic process studies will be focused in arid North Africa, semi-arid areas in the southwest U.S., tetonically-active areas in the south central Andes, and the volcanically active Galapagos Islands. Oceanography experiments will be focused in the Gulf Stream, the East North Atlantic, and in the Southern Ocean. Calibration ground equipment will be deployed at supersites in southern Germany, The Netherlands, and Australia, and at other Supersites. Pertinent data, including the geographic locations of calibration devices at the supersites, will be archived for use with SIR-C/X-SAR data by future investigators.
Table 4: SIR-C/X-SAR Supersites
DISCIPLINE SUPERSITES BACKUP SUPERSITES
Calibration Flevoland, The Netherlands Matera, Italy Sarobetsu, Japan
Kerang, Australia Palm Valley, Australia Eastern
Oberpfaffenhofen, Germany Pacific
Western Pacific (rain
experiment)
Ecology Manaus, Brazil Raco, Amazon Survey, Brazil Prince
Michigan Duke Forest, North Albert, Saskatchewan, Canada
Carolina Howland, Maine Altona, Manitoba
Electromagnetic Theory Safsaf, Sudan
Geology Galapagos Islands Sahara Hawaii Saudi Arabia Hotien
Death Valley, California East, China
Andes Mountains, Chile
Hydrology Chickasha, Oklahoma Ötztal, Mahantango, Pennsylvania
Australia Bebedouro, Brazil Mammoth Mountain, California
Montespertoli, Italy
Oceanography East-North Atlantic Gulf Equatorial Pacific North Sea
Stream Southern Ocean
Andes Mountains, South America
Titles of Investigations:
I. SIR-C/X-SAR Analysis of Topography and Climate in the Central Andes
II. SIR-C/X-SAR Radar Investigations of Volcanism and Tectonism in the Northern Andes
Principal Investigators:
I. Brian Isacks
Cornell University
II. Chuck Wood
University of North Dakota
Site Description:
The Andes Mountains of South America provide an ideal laboratory to study the effects of both modern and Quaternary climate changes. The mountain belt traverses a latitudinal transect of over 60deg. from equatorial to sub-polar regions. Since at least four million years ago, the glaciers and icesheets of the Andes have expanded and contracted in response to the Earth's changing climate. These changes have left an indelible geomorphic signature on the landscape that can be used to reconstruct changes in temperature and precipitation that caused the glacial advances and retreats. In addition, the modern glacier movements in the Andes provide a valuable record of historic and ongoing climate change in the region. During the last 100 years, most glaciers along the entire range of the Andes have shown marked retreat.
The Patagonian Lake District in Argentina and Chile is of special interest because it includes South America's most extensive modern, as well as past, glaciers and ice fields. The region's glacial history is one of the most studied in all of the Andes (e.g., Caldenius, 1932; Mercer, 1976, 1983; Morner and Sylwan, 1989). Throughout the Quaternary, the Patagonian ice caps and glaciers have had the largest volume of ice in the southern hemisphere outside of Antarctica (and only exceeded by the ice fields of southeast Alaska and the Karakorum in the northern Hemisphere). Previous glaciations produced a series of extensive moraines, the earliest of which is at least 700,000 years old. From these moraines it is possible to infer the extent and timing of the previous glaciations and thereby reconstruct the history of climate change in this region.
The semi-arid climate of the region resulting in sparse vegetation and slow weathering rates make it possible to use SIR-C/X-SAR to estimate moraine chronology from space. Moraine sequences can be differentiated with SAR because of the correlation of surface roughness with moraine age. Older moraines become smoother through time as a result of boulder weathering and soil development; in contrast, the angular and more dense boulder distribution of the younger moraines presents a rougher surface. The ability of SAR to categorize moraines based on age has been demonstrated through analysis of airborne SAR images of the Mono Basin moraines in California. The area was chosen as a "proof-of-concept site" because of its similarity to the Patagonian site with expressions of multiple glaciation and sparse vegetation.
The Mono Basin moraines are well studied with established chronologies and have been dated by cosmogenic exposure with 36Cl. In an effort to further constrain the timing of glaciations and provide calibration for the radar measurements, the Cornell Andes Project collected samples from boulders on all four of the major moraine sequences in the Patagonian Lago Buenos Aires area. These samples are now being dated with the 36Cl exposure dating technique.
SIR-C/X-SAR images of the moraines in the Andes will be analyzed with the techniques established by the Cornell Andes Project to obtain ages for the moraines. The site will act as a moraine age "calibration site" for the Andes enabling SAR dating technique to be extended to other Andean moraines imaged by SIR-C/X-SAR and future SAR missions. From this cornerstone location an extensive glacial chronology for the Andes may be constructed from spaceborne satellites supplying new information regarding the dynamics of past global climate change.
The two Patagonian ice caps adjacent to the supersite (and criss-crossed by the SIR-C/X-SAR swaths) are among the least studied of the earth's major alpine snow and ice field due to remoteness and cloud cover, although some work has been done (e.g. Aniya, 1988). SIR-C/X-SAR images across the Patagonian Lake District will provide a powerful means to determine the present-day glacier and snowline extents, and to estimate equilibrium line altitudes (ELAs) on glaciers by differentiation of snow and ice facies. Estimation of the modern regime, required for comparison with Quaternary condition to infer paleotemperatures and paleoprecipitation, will also contribute important baseline data for measurements of future changes in this climatically sensitive region.
Objectives:
I. a) Calibrate radar measurements of the ages of glacial moraines.
b) Determine modern and Pleistocene snow-line altitudes and gradients along Andean latitudinal transect.
c) Provide new baseline measurements of the state of the Patagonian ice caps and glaciers.
II. a) Increase understanding of the volcano-tectonic history of Andes mountain range by testing and extending the volcano-tectonic segmentation model.
b) Develop radar models for detecting and mapping pyroclastic and mudflow deposits at dangerous volcanoes of the Andes.
Field Measurements:
I. a) Additional 36Cl measurements of moraine ages.
b) Measurement of images moraine surface roughness.
c) Observations of snow and ice conditions at time of imaging.
Crew Observations:
1) Crew Journal: Monitor dust storms and determine the extent of the snow line and glaciers.
2) Cameras: Hasselblad and Linhoff cameras will be used to photograph the site. Stereo and low sun angle images are requested.
Coverage Requirements:
Two polarimetric swaths crossing morainal sequences of Lago Buenos Aires. Polarimetric swaths crossing ice caps.
Anticipated Results:
I. a) Determination of the timing of late Quaternary Andean glacial advances.
b) New information about the degree of correlation between Northern and Southern Hemisphere Quaternary climate change.
c) Baseline data for determination of future changes in volumes of Patagonian snow and ice.
II. a) Greatly improve geologic knowledge of poorly mapped, frequently cloud-covered, volcanically active arc;
b) Increase understanding of a seismically unusual subduction setting;
c) Develop an optimal interpretation of radar data for detection and mapping of pyroclastic/lahar deposits in tropical environments;
d) Improve understanding of distribution and character of poorly mapped deposits at Ruiz and other explosive volcanoes in the area; and
e) Recognize prehistoric pyroclastic deposits around other Andean volcanoes thereby increasing awareness of volcanic hazards.
References:
Aniya, M., 1988, Glacier inventory for the northern Patagonia icefield, Chile, and variations 1944/45 to 1985/86.
Barazangi, M, and B. Isacks, 1976, Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America. Geology, 4, 686-692.
Caldenius, C. G., 1932, Las glaciaciones cuaternarias en la Patagonia y Tierra Del Fuego, Geografiska Ann., 14, 1-164.
Hall, M. L. and C. A. Wood, 1985. Volcano-tectonic segmentation of the Northern Andes. Geology 13, 203-207.
Mercer, J. H., 1976, Glacial History of Southernmost South America, Quaternary Res. 6, 125-166.
Mercer, J. H., 1983, Cenozoic Glaciation in the Southern Hemisphere, Ann. Rev. of Earth and Planetary Sci., 11, 99-132.
Morner, N. A., and C. Sylwan, 1989, Magnetostratigraphy of the Patagonian Moraine Sequence at Lago Buenos Aires, J. of S. American Earth Sci., 2, 385-389.
Wood, C. A. and D. Moberger, 1983. Segment length: a tectonic control of arc volcanism. EOS 64, 845.
Title of Investigation:
I. Microwave Remote Sensing Data From a Spaceborne Platform as a Tool to Monitor the Hydrological Cycle of a Floodplain Area ("Varzea") at Northeast Brazil.
Principal Investigator:
I. Dr. João Vianei Soares
Instituto de Pesquisas Espaliers (INPE)
Site Description:
This experiment will be conducted at the Bebedouro Irrigation Project, located in the northern Rio São Francisco valley, northeast Brazil, in the state of Pernambuco, approximately 42 km north of Petrolina . The irrigated area is 1750 ha; the size of individual fields varies between 5 and 12 ha. The regional climate is classified after Köppen as Bsh'w-type, with a minimum air temperature of 14deg.C and a maximum temperature of 39deg.C, and an average annual precipitation of 391.5 mm; the relative humidity varies from 56.7 to 67.1% and the annual evaporation is 2106 mm (De Faria, et al., 1982).
Agriculture plays an important economic and social role in Brazil. One of the major problems related to Brazilian agriculture is estimating planting areas and their productivities. Remote sensing techniques (Landsat-MSS, TM, and SPOT) have been useful for performing this work. Summer crops (December/April) account for more than 90% of the agricultural production. Due to the coincidence of the summer growing season and the rainy season (precipitation above 1200 mm at the crop-producing region in southern and southeastern Brazil), it is difficult to obtain useful remote sensing data at the visible and infrared wavelengths on a regular basis. Spaceborne microwave remote sensing techniques are considered a potential alternative to solving this problem.
Floodplains of major Brazilian rivers have high potential for the expansion of Brazilian agriculture. This is especially true in semi-arid regions in northeastern Brazil where long drought periods cause many social and economic problems. According to M. Alves da Silva, et al., 1981, there are approximately 800,000 ha of floodplains suitable for irrigation at the Rio São Francisco valley (a Brazilian south-north flowing river system). Of these, approximately 90,000 ha are operational and 75,000 ha are being implemented. The Bebedouro test site includes an experimental irrigation project which is managed by EMBRAPA/CPATSA (Empresa Brasileira de Pesquisa Agropecuária/Centro de Pesquisa Agropecuária do Trópico Semi-Árido). According to studies performed at CPATSA (M. Alves da Silva, et al., 1981), a major hydrologic problem related to these floodplains is salinization due to improper irrigation practices.
Within this context, irrigation techniques that integrate hydrological data are of great relevance. Microwave remote sensing techniques are of special interest to estimate surficial soil moisture, one of the fundamental components of the hydrological cycle. The multiparameter characteristics of the SIR-C/X-SAR experiment, as described in the Shuttle Imaging Radar-C Science Plan (1986) and the X-SAR Science Plan, are well suited for the experiment to be conducted at Bebedouro.
Objectives:
I. a) Develop an algorithm to monitor the hydrological cycle over agricultural areas based on SAR imagery and meteorological data.
b) Develop algorithms to classify and enhance digital SAR images. These algorithms would be helpful for applications with future spaceborne SAR systems (EOS, ERS-1, RADARSAT).
c) Verify the possibility of discriminating among cultures present at the test site by the time of the SIR-C/X-SAR experiment and to confirm the qualitative attenuation properties of the vegetation cover as related to the radar parameters frequency, polarization, and angle of incidence.
d) Establish a database on a multiparameter SAR system relying on soil/vegetation descriptors.
Field Measurements:
I. In situ data acquisition will include:
a) Routine meteorological data (i.e. air temperature and humidity, wind velocity, global radiation, pan evaporation, precipitation rate and frequency) will be obtained from EMBRAPA/CPATSA Agrometeorological Station.
b) Depth of water at the irrigation plot;
c) Micro-meteorological tower(s) for automatic estimation of surface fluxes based on a simplified aerodynamic method following Itier, B., 1981; Perrier, A., et al., 1975; and Perrier, A., et al., 1976. These data will be employed for comparison purposes at local scale.
d) Soil samples representative of the entire area will be acquired for granulometric analysis.
e) Soil samples (about 10 ha; 100 samples/day) from the 0-5 cm layers from the center of the site will be acquired for soil moisture measurements following the gravimetric method of Wang, et al, 1986. These data will be used to calibrate SIR-C/X-SAR data.
f) Acquisition of other relevant agronomic parameters, such as density of seeding, soil type (pedological maps), roughness, and estimation or measurement of the Leaf Area Index (LAI) of cultures.
g) Acquisition of characteristic curves of the soils available at CPATSA, of a soil-water profile (by neutron probe sampler), and of the suction potential profile (by tensiometers) to confirm the actual characteristic curves and estimate the representative water content of the soil (W2).
Ancillary data from airborne and spaceborne sensors will include:
a) Surface temperature (1 km x 1 km pixel) from AVHRR/NOAA-7 and ancillary data set to fit the two layer bare soil models (six images/day can be registered at INPE facilities).
b) Surface temperature from an airborne infrared radiometer (Barnes PRT-5). These ancillary data will be used to fit the simulated surface temperature (from the two layer method).
c) Backscattering coefficient to be obtained from a dual frequency/dual polarization airborne scatterometer (C- and X-bands), from INPE, if it is operational at the time of the experiment;
d) To improve regional monitoring, we will acquire multispectral images from SPOT or TM by the time of the SIR-C/X-SAR overflight.
e) Color infrared aerial photographs of the area of interest.
Crew Observations:
1) Crew Journal: Document weather, floodplain conditions, extent of inundation, and the condition of the vegetation canopy.
2) Cameras: Linhoff and Hasselblad cameras will be used to photograph the site and particularly the floodplain.
Coverage Requirements:
The minimum coverage requirements for this site are four (4) passes, preferably from the same direction.
Anticipated Results:
I. a) Establishment of a methodology to estimate soil moisture and evaporation rates at a regional scale for irrigation projects, climatological studies, and as an input to numerical models for weather forecasting, based on operational SAR systems such as the Earth Observing System (EOS), envisaged for the mid-90's;
b) Development of a data base relying on a multiparameter SAR system and its interaction with different tropical agricultural crops; and
c) Development and acquisition of software for the classification and enhancement of digital SAR images, which will be helpful for agricultural and hydrological studies in the future (EOS, RADARSAT, etc.).
References:
Alves da Silva, M., E. N. Choudhury, L. A. Gurovich, and A. A. Millar, 1981, Metodologia para determinar as necessidades de água das culturas irrigadas, in EMBRAPA/CPATSA Pesquisa em Irrigação no trópico Semi-Arido: solo - água - planta, Petrolina, PE, EMBRAPA/CPATSA, Boletim de Pesquisa, 4, 25-44.
de Faria, C. M. B., F. J. G. Cabral, M. L. Ferraz, E. N. Choudhury, and C. E. Martins, 1982, Avaliação da Fertilidade do Solo do Projeto de Irrigação de Bebedouro em Petrolina, Petrolin, PE, EMBRAPA/CPATSA, Boletim de Pesquisa , 12, 21p.
Itier, B., 1981, Une methode simple pour la mésure de l'évapotranspiration réelle à l'échelle de la parcelle, Agronomie, 1(10), 869-876.
Perrier, A., B. Itier, J. M. Bertolini, and A. B. de Pablos, 1975, Mesure automatique du Bilan d'énergie d'une culture, Exemples d'Application. Ann. Agron., 26(I), 19-40.
Perrier, A., B. Itier, J. M. Bertolini, and N. Katerji, 1976, A New Device for Continuous Recording of the Energy Balance of Natural Surfaces, Agricultural Meteorology, 16, 71-84.
Shuttle Imaging Radar-C Science Plan, September 1, 1986, Jet Propulsion Laboratory Publication 86-29, Pasadena, California.
Wang, J. R., E. T. Engman, J. C. Shiue, M. Ruzek, and C. Steinmeier, 1986, The SIR-B Observations of Microwave Backscatter Dependence on Soil Moisture, Surface Roughness, and Vegetation Covers, IEEE Trans. on Geosci. and Rem. Sensing, GE-24, no. 4, 510-516.
Chickasha,
Oklahoma
Titles of Investigations:
I. Applications of SIR-C/X-SAR Synthetic Aperture Radar to
Hydrology
II. SIR-C/X-SAR Measurements of Soil Moisture, Vegetation and Surface
Roughness, and Their Hydrological Application
Principal Investigators:
I. Ted Engman
Goddard Space Flight Center
II. James Wang
Goddard Space Flight Center
Site Description:
The Little Washita River Watershed covers 235.6 square miles and is a
tributary of the Washita River in southwest Oklahoma (Fig. 1). The watershed
is in the southern part of the Great Plains of the United States. The climate
is classified as moist and subhumid; the average annual rainfall was 29.42
inches for the 24 years of data collection by the Agricultural Research
Service. Summers are typically long, hot, and relatively dry, and winters are
typically short, temperate, and dry but are usually very cold for a few weeks.
Much of the annual precipitation and most of the large floods occur in the
spring and fall. A more detailed review of the climate and its variability for
this watershed and the surrounding area is presented by the Staff, Water
Quality and Watershed Research Laboratory (1983) (Allen, P. B. and Naney, J.
W., 1991).
The Little Washita River Watershed in southwest Oklahoma is unique in that
over a period of several years it has had an unusually large amount of soil and
water conservation treatment and research. In 1936 the eastern portion of the
watershed was chosen as part of a national demonstration project for soil
erosion control. In the late 1930s the Civilian Conservation Corps did
extensive erosion control work, including terracing, drop-structure building,
gully plugging, and tree planting. Since establishing county offices in the
1940's, the U. S. Department of Agriculture's (USDA) Soil Conservation Service
(SCS) has applied extensive soil and water conservation structures and
measures, including terraces, diversions, farm ponds, floodwater-retarding
reservoirs, gully plugging and smoothing, scrub timber removal, and land use
planning.
In 1961, the USDA's Agricultural Research Service, in compliance with U. S.
Senate Document 59 (1959), began collecting hydrologic data on the Little
Washita River Watershed and other watersheds in the vicinity to determine the
downstream hydrologic impacts of the SCS floodwater-retarding reservoirs. This
data collection process involved an intensive rain gauge network and a stream
gauging station near the watershed outlet that provided data on continuous
flow, suspended sediment transport, and, for a few years, water quality. Data
on groundwater levels and channel geometry were also collected to determine
possible effects of the treatment program.
In 1978, this watershed was one of seven watersheds chosen across the nation
for the Model Implementation Project (MIP), which was jointly sponsored and
administrated by the USDA and the U. S. Environmental Protection Agency. The
main objective of the MIP was to demonstrate the effects of intensive land
conservation treatments on water quality in watersheds that are larger than
about 25 square miles.
Objectives:
I. a) Determine and compare soil moisture patterns within one or more
humid watersheds using SAR data, ground-based measurements, and hydrologic
modeling.
b) Characterize the hydrologic regime within a catchment and identify the
runoff producing characteristics of humid zone watersheds.
c) Use radar data as the basis for scaling up from small scale, near-point
process models to larger scale water balance models necessary to define and
quantify the land phase of GCMs.
II. a) Analyze the SIR-C/X-SAR response to soil moisture, vegetation, and
surface roughness.
b) Combine the visible and near-infrared data with the SIR-C/X-SAR data to
improve the range and accuracy of vegetation classification.
c) Test theoretical models for microwave propagation with SIR-C/X-SAR and
microwave radiometric measurements over rough surfaces.
d) Evaluate a water balance model using SIR-C/X-SAR derived soil moisture
values and other ancillary data.
Field Measurements:
I. a) WASHITA-92 is a Multisensor Airborne Campaign (MAC) for hydrology
(MACHYDRO) that was conducted at the Chickasha supersite during the period of
June 8-18, 1992. This experiment emphasized the microwave sensors on the two
NASA aircraft; the C-130 and the DC-8. Listed below are the instruments flown
by the two aircraft.
C-130 Thermal Infrared Multispectral Scanner (TIMS)
Thematic Mapper Simulator (NS001)
Electronically Scanning Thinned Array Radiometer (ESTAR)
Cameras
37 GHz radiometer
Laser Profiler (from the USDA)
DC-8 Synthetic Aperture Radar (SAR) - C-, L-, and P- bands,
polarimetric
b) During WASHITA-92 a large number of field measurements were made to support
and to provide detailed hydrologic data for analysis. Approximately sixty
people, scientists, students, and technicians took part in these ground data
collection activities. The field data collected included both the routine
hydrology data (rainfall, runoff, met data) and special data for the
experiment, including:
Micrometerological measurements (eddy correlation, Bowen ratio, etc.)
Boundary layer profiling (radiosondes)
Land cover and vegetation mapping
Surface roughness
Profile soil and surface soil moisture (grid and transects)
Bulk density measurements
Reflectance and emissivity
Truck based L-band radar and trihedral corner reflectors
Salinity and lake water temperature
Satellite data (SPOT, ERS-1, AVHRR)
c) The meterological conditions during the experiment enabled us to follow a
long but gradual dry-down of the soil moisture. Previous to the first flights
(June 10), there had been 26 consecutive days of rain in Oklahoma and
conditions were extremely wet with a considerable amount of standing water.
The last rain over the watershed occurred on the morning of June 9 and good
drying conditions prevailed until after the last flight on June 18.
d) The WASHITA-92 experiment will provide a good background to the up-coming
SIR-C/X-SAR missions. During the mission, many of the same measurements will
be made but the emphasis will be on a few detailed measurements at selected
sites. These will be used to verify the radar performance and to provide the
bridge between the WASHITA-92 and the SIR-C/X-SAR experiments.
II. Activities of the ground truth data collection, as well as other relevant
satellite and ancillary data acquisitions.
Crew Observations:
1) Crew Journal: Describe the weather, cloud cover, and the vegetation
at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the site. Low
sun angle images are requested.
Coverage Requirements:
The minimum coverage requirements for this site is three (3) passes.
Anticipated Results:
I. a) Development of a technology for measuring soil moisture in natural
catchments for humid regions using spaceborne radar.
b) Development of a new way to characterize the contributing areas of
natural, humid zone catchments.
c) Development of a technology for modeling soil moisture distributions in
natural catchments based on spaceborne measured data.
d) Development of procedures for parameterizing macro-scale models capable of
representing the land phase processes for GCMs.
e) Development of procedures to scale up hydrologic processes from point or
small area to catchment scales using SAR data.
f) Validation of vegetation models for estimating the backscatter component
of overlying vegetation canopies and the underlying soil condition.
II. a) Development of an algorithm to retrieve the SIR-C/X-SAR soil moisture,
vegetation and surface roughness parameters.
b) The relationship between surface parameters and imaging radar signatures
will be established. An algorithm based on this relationship to retrieve the
surface parameters will be developed.
c) Verify that an imaging radar system with multiple frequencies and
polarizations is an efficient tool for vegetation classification. Assessment
will be made of the classification scheme improvement when visible and
near-infrared data are included.
d) Using SIR-C/X-SAR and ground measured roughness data, assess the validity
of current theoretical models for microwave backscatter from rough surfaces.
e) Using the SIR-C/X-SAR retrieved soil moisture and other ancillary data,
verify the validity and limitation of a generalized water balance model.
Reference:
Allen, Paul B. and James W. Naney, 1991, Hydrology of the Little Washita
River Watershed, Oklahoma: Data and Analyses, United States Department of
Agriculture, Agricultural Research Service, ARS-90.
Death Valley, California
Titles of Investigations:
I. Climate Change and Neotectonic History of Death Valley
II. Alluvial Fan Evolution in the Western Great Basin
III. Development of a Technique to Relate Eolian Roughness to Radar Backscatter Using Multi-Parameter SIR-C Data
IV. Evaluation of SIR-C/X-SAR Imagery for Geologic Studies in Arid and Semi-arid Regions
V. Comparative Lithological Mapping Using Multipolarization, Multifrequency Imaging Radar and Multispectral Optical Remote Sensing
VI. SIR-C Surface and Subsurface Responses from Documented Test Site Localities in Death Valley, the Sahara, Namib, and Kalahari Deserts, Africa, and the Jornada del Muerto, New Mexico
VII. Multi-Frequency, Multi-Polarization External Calibration of the SIR-C/X-SAR Radars
Principal Investigators:
I. Dr. Tom Farr
Jet Propulsion Laboratory
II. Dr. Allan Gillespie
University of Washington
III. Dr. Ron Greeley
Arizona State University
IV. Dr. Huandong Guo
Academia Sinica
V. Dr. Fred Kruse
University of Colorado
VI. Dr. Gerald Schaber
US Geological Survey
VII. Dr. Anthony Freeman
Jet Propulsion Laboratory
Site Description:
Death Valley is a north-south trending fault-bounded valley in the southern Great Basin of the United States. Elevations range from 70 m below sea level to more than 3300 m above sea level (Telescope Peak). Climate and vegetation vary accordingly, from subalpine pine forest at higher elevations, to arid creosote on the piedmonts, to sparse salt-tolerant plants in the valley bottom. Surficial process investigations are concentrating mostly on the piedmont and valley floor. They include studies of the formation of alluvial fans through climatic and tectonic effects, the nature and rates of weathering processes on the fans, soil formation, and the transport of sand and dust by the wind. These are long-term studies with the goal of better understanding the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios.
Death Valley is a good site for development and testing of techniques for remote lithologic mapping because of the wide range of rock types exposed in a range of environments. The Panamint Mountains, bounding the valley on the west and the Grapevine Mountains in the north part of the valley, are composed of a variety of igneous, metamorphic, and sedimentary rock types. In addition, there are known areas of alteration that have created economic deposits of minerals.
As part of the secondary objectives, Death Valley has been used as a test site for the development of radar interferometric techniques. At present, both Seasat and TOPSAR data sets are available and ERS-1 interferometer images will be acquired in 1993. In addition, a SPOT stereo-pair has been acquired and is being reduced to digital topography for comparison to the interferometric data. These data are now being used in the studies described above. Soils have developed in Death Valley in a wide range of salinity. This makes possible studies of the radar signature of soils that have suffered a buildup of salt- a growing problem in marginal lands. Finally, at the north end of the valley lies Ubehebe Crater, a series of volcanic craters (maars) created by explosion with very little associated lava. Volcanologists can study the radar signatures of the craters and explosive deposits.
Objectives:
I. a) The goal of the proposed research is to determine the history of Quaternary climate change for a portion of Death Valley for inclusion in global paleoclimate models and reconstructions of the tectonic history of the area.
b) Compare surface modification processes that have operated in Death Valley to those in similar areas of northwestern China.
II. a) Describe systematic morphologic changes with surface age in terms of multiparameter radar backscatter.
b) Construct for the studied fans a depositional and weathering history based on SAR and other images and field investigations.
c) Use the depositional and weathering history of the study area to constrain paleoclimatic interpretations.
d) Use project as prototype for paleoclimate study of entire Great Basin or other geomorphic provinces.
e) Test the hypothesis that spectral mixing analysis can be applied to multiparameter SAR images of alluvial fans in arid and semiarid regions.
f) Define radar endmembers physically, in terms of Bragg scattering, volume scattering, specular and corner reflectors, and dielectric constant, etc..
g) Develop and test mixing models for comparative analysis of images spanning multiple spectral regions.
III. a) To develop a technique to obtain values of aeolian roughness for geologic surfaces from values of surface roughness determined from SIR-C/X-SAR.
b) Define the optimal combination of radar parameters from which aeolian roughness can be derived.
c) Gain an understanding of the physical processes behind the empirical relationship.
IV. a) Conduct a radar penetration study be measurement for typical surficial covers.
b) Develop a theoretical model of radar scattering for penetration study.
c) Develop a limited inversion of radar scattering model for applications of SIR-C/X-SAR data.
V. a) Develop a better understanding of depositional and erosional processes through a study of compositional and geomorphic variation.
b) Develop a better understanding of the current geomorphic expression of rock surfaces; characterize the geometry, and indirectly, the composition of rock units.
c) Compare radar characterization with visible/infrared characterization of surface materials for both vegetation-free and vegetated areas.
d) Evaluate multidimensional image processing techniques for analyzing multispectral/ multipolarization/multiple incidence angle radar data.
e) Evaluate the utility of precision radargrammetry to improve lithological mapping capabilities.
f) Map the character and distribution of lithological variation with SIR-C/X-SAR.
g) Provide hands-on radar remote sensing experience to graduate students.
VI. a) Determine the optimum SIR sensor configuration for detection of desert duricrust and to use this understanding to reconstruct the paleoclimatic history for a portion of Death Valley.
VII. a) Assess the accuracy at which the SIR-C/X-SAR standard data products can be calibrated.
b) Study the cross-calibration between three independent multi-polarization systems: SIR-C, the NASA/JPL DC-8 SAR, and the University of Michigan ground-based polarimetric scatterometer.
c) Evaluate the calibration "stability" of the SIR-C/X-SAR.
d) Develop a cost-effective calibration plan which includes development of inexpensive polarimetric active calibrators.
Secondary objectives include: tests of interferometry and use of digital topography, studies of soil salinization, and volcanology studies.
Field Measurements:
I. a) Establish of a few key "calibration" sites at which ages of geomorphic surfaces will be determined, remote sensing signatures of the surfaces measured, and the variation of surfaces between and within drainage basins examined.
II. a) Select study site(s) in Death Valley/Owens Valley to exploit existing geomorphic, soils, and geochronology data, for a sequence of alluvial fans deposited during the last 0.5 Ma.
b) Make precise measurements of integrated weathering rates for each dated surface, which can then be analyzed jointly to construct a history of weathering rates and rate changes for selected parameters (e.g., oxidation, hydration, clast disintegration, and aeolian silt redistribution).
III. a) Collect wind data and microtopography measurements at key sites in Death Valley.
b) Compute statistical descriptions of surface roughness from large- (m) and small- (cm) scale topographic profiles measured in the field on each surface.
IV. No field measurements are planned.
V. a) Field work will include measurements of surface roughness, dielectric constant(s), surface visible and infrared spectral measurements. In addition, geologic maps will be used to determine geomorphic units.
b) Supporting remote sensing data include: AIRSAR data, digital elevation models (DEMs) for the field site, co-registered AVIRIS, TM, and TIMS data, helicopter stereo pairs for selected geomorphic surfaces, and color aerial photographs.
VI. a) Extend laboratory measurements and the SIR-A/B geometric scatter model for calichified sediments in arid, sand-covered terrains to higher frequencies and a wider range of sample physical parameters.
b) Document and establish limits on SIR-C/X-SAR signal behavior in hyperarid-to-semiarid regions. Specifically, document the effects of surficial and subjacent geologic conditions on SIR-C response in various sensor configurations.
VII. a) Deploy inexpensive trihedral corner reflectors to characterize co-polarized channel imbalance in magnitude and phase over an area wider than that covered by the active calibrators in the primary calibration area.
Crew Observations:
1) Crew Journal: Describe sand or dust storms, weather at the site, alluvial fans surface and dune orientations.
2) Cameras: Linhoff and Hasselblad will be used to obtain color photographs of the site. A polarizing filter and infrared film are requested during some orbits.
Coverage Requirements:
The minimum coverage requirements for this site are three passes at incidence angles of 30-50deg., and one pass in quad polarization mode.
Anticipated Results:
I. a) Maps of geomorphic surfaces with ages attached to them will be a major step toward understanding the climatic history of this region of the earth.
b) Comparisons of this climate record with climate records from the oceans and other continents will help advance the global synthesis of climate change.
c) Answers to the questions of how unique and how globally representative remote sensing signatures are will directly affect our future ability to extrapolate the signatures to global studies of climate change.
d) Determination of past slip rates on some active faults in Death Valley by a knowledge of the ages of offset surfaces.
II. a) New technique for "unmixing" multiparameter radar images into meaningful components (e.g., volume-scattering surfaces or "vegetation", Bragg-scattering surfaces, etc.).
b) An alternative to "extended spectral signatures" for joint analysis of disparate images spanning multiple spectral regions.
c) Better history of bajada surface evolution than available from chemical weathering studies alone.
d) Improved knowledge of Pleistocene paleoclimate in the western Great Basin.
e) Test of predictive models for climate/paleoclimate and for inferences from paleoecological studies.
III. a) Determination of an empirical relationship between measurements of microtopography, aerodynamic roughness, and microwave energy.
b) Development of an equation expressing this relationship. This expression will form the basis of a technique for using spaceborne SAR data to determine a roughness parameter for use in aeolian sand transport rate equations.
c) The results also will be used to validate models of aeolian response to surface roughness.
IV. a) Dependence of radar penetration depth.
b) Interpretation of SIR-C/X-SAR imagery over areas of Death Valley.
c) Evaluation of quantitative application of SIR-C/X-SAR data.
V. a) A better understanding of processes involved in deposition and erosion of sedimentary and igneous rocks.
b) An improved understanding of lithological variation and its relation to geomorphic expression of rock surfaces.
c) Improved understanding of the relation of multiparameter radar image characteristics to rock/soil/vegetation physical properties.
d) An improved understanding of the strengths and weaknesses of multispectral/ multipolarization/multiple incidence angle radar and how it can be used to compliment visible/infrared remote sensing.
e) Development of extended spectral signatures for geologic materials and vegetation.
f) Improved lithological mapping capabilities.
g) Innovative image processing algorithms and analysis techniques for multispectral/ multipolarization/multiple incidence angle radar.
VI. a) An improved understanding of radar backscatter and penetration in hyperarid-to-semiarid terrains that was initiated during our SIR-A/B investigations (Elachi, Roth and Schaber, 1984; Schaber et al., 1986).
b) Refinement of synergistic remote methods to identify various types and stages of datable, authigenic CaCO3 deposits related to successive changes in climate and surface geologic processes during the Quaternary.
c) Improved models of geometric scattering effects on SIR signal penetration.
d) New data on the spatial and chronological distribution of semiarid paleoclimatic zones in Africa.
VII. a) Full polarimetric end-to-end characterization of the SIR-C/X-SAR system in the primary calibration target area within the limitations of instrument accuracy.
b) A better understanding of polarimetric calibration of space-borne microwave synthetic aperture radar.
References:
Arvidson, R. E., M. Shepard, S. B. Petroy, J. J. Plaut, D. L. Evans, T. G. Farr, R. Greeley, N. Lancaster, and L. R. Gaddis, 1992, Characterization of lava flow degradation in the Pisgah and Cima volcanic fields, California, using Landsat thematic mapper and AIRSAR data, GSA Bulletin, in press.
Blumberg, D. and R. Greeley, in press, Field Studies of Aerodynamic Roughness, Journal of Arid Environments,
Daily, M., C. Elachi, T. Farr, and G. Schaber, 1978, Discrimination of Geologic Units in Death Valley Using Dual Frequency and Polarization Imaging Radar Data, Geophys. Res. Let., 5, 889-892.
Daily, M., T. Farr, C. Elachi, and G. Schaber, 1979, Geologic Interpretation from Composited Radar and Landsat Imagery, Photogram. Engr. Rem. Sens., 45, 1109-1116.
Elachi, C., L. E. Roth, and G. G. Schaber, 1984, Spaceborne Radar Subsurface Imaging in Hyperarid Regions, IEEE Trans. Geosci. Rem. Sensing GE-22, No. 4, 383-388.
Evans, D. L., T. G. Farr, M. Vogt, C. Bruegge, J. Conel, R. E. Arvidson, S. B. Petroy, J.J. Plaut, M. Dale-Bannister, E. Guiness, M. Shepard, R. Greeley, N. Lancaster, L. Gaddis, J. Garvin, D. Deering, J. R. Irons, F. Kruse, and D. J. Harding, 1992. The Geologic Remote Sensing Field Experiment, IEEE Trans. Geo.sci and Rem. Sensing, in press.
Gillespie, A.R., A.B. Kahle, F.D. Palluconi, 1984, Mapping Alluvial Fans in Death Valley, California, Using Multichannel Thermal Infrared Images, Geophys. Res. Let., 11, 1153-1156.
Greeley, R., N. Lancaster, R. J. Sullivan, R. S. Saunders, E. Theilig, S. Wall, A. Dobrovolskis, B. R. White, and J. D. Iversen, 1988. A relationship between radar backscatter and aerodynamic roughness: preliminary results. Geophys. Res. Let., 15, 565-568.
Greeley, R., L. Gaddis, N. Lancaster, A. Dobrovolskis, J. Iversen, K. Rasmussen, S. Saunders, J. van Zyl, S. Wall, H. Zebker, and B. White, 1991. Assessment of aerodynamic roughness via radar observations. Acta Mechanica, Suppl. 2, 77-88.
Kierein-Young, K. S., and F. A. Kruse, 1991, Quantitative Investigations of Geologic Surfaces Utilizing Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and Polarimetric Radar (AIRSAR) data for Death Valley, California, in Proceedings, International Symposium on Remote Sensing of Environment, Thematic Conference on Remote Sensing for Exploration Geology, 8th, 29 April - 2 May 1991, Denver, Colorado, Environmental Research Institute of Michigan, Ann Arbor, 495-506.
Kierein-Young, K. S., F. A. Kruse, and A. B. Lefkoff, 1992. Quantitative analysis of surface characteristics and morphology in Death Valley, California using AIRSAR data. In Proceedings, IGARSS '92, 26-29 May, 1992, Houston, TX, IEEE Cat. No. 92CH3041-1, v. 1, 392-394.
Kierein-Young, K. S., and F. A. Kruse, 1992, Extraction of Quantitative Surface Characteristics from AIRSAR Data for Death Valley, California, in Summaries of the Third Annual JPL Airborne Geosci. Workshop, AIRSAR Workshop, JPL Publication 92-14, 3, 46-48.
Kruse, F. A., 1987, Use of Airborne Imaging Spectrometer data to map minerals associated with hydrothermally altered rocks in the northern Grapevine Mountains, Nevada and California. Rem. Sens. Env., 24, 1, 31-51.
Kruse, F. A., A. B. Lefkoff, and J. B. Dietz, 1993. Expert System-Based Mineral Mapping in northern Death Valley, California/Nevada using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Rem. Sens. Env., Special Issue on AVIRIS, May-June 1993, in press.
Kruse, F. A. and J. B. Dietz, 1991. Integration of visible-through microwave-range multispectral image data sets for geologic mapping. In Proceedings of the Cinquième Colloque International, Mesures Physiques et Signatures En Tèlèdètection, 14-18, January 1991, Courchevel, France, European Space Agency, esa SP-319, v. 2, 481-486.
Kruse, F. A., J. B. Dietz, and K. S. Kieran-Young, 1991 (extended abst.). Geologic Mapping in Death Valley, California/Nevada using NASA/JPL Airborne Systems (AVIRIS, TIMS, and AIRSAR). In Proceedings of the 3rd Airborne Synthetic Aperture Radar (AIRSAR) Workshop, 23-24 May 1991, JPL Pub. No. 91-30, 126-127.
Schaber, G.G., G.L. Berlin, W.E. Brown, Jr., 1976, Variations in Surface Roughness Within Death Valley, California: Geologic Evaluation of 25-cm-Wavelength Radar Images, Geol. Soc. Amer. Bull., 87, 29-41.
Schaber, G. G., C. S. Breed, J. F. McCauley, G. R. Olhoeft, and B. J. Szabo, 1986. Controls on signal penetration and subsurface backscatter from the Shuttle Imaging Radar: Summaries, Twentieth International Symposium on Remote Sensing of the Environment (Nairobi, Kenya, Dec. 4-10, 1986). Environmental Res. Instit. of Michigan, Ann Arbor, 78-79.
Titles of Investigations:
I. Estimation of Total Aboveground Biomass in Southern United States Old-Field Pine Stand Using SIR-C/X-SAR Data
II. Biomass Modeling of Pine Forests of North America with SIR-C/X-SAR for Input to Ecosystem Models
Principal Investigators:
I. Dr. Eric S. Kasischke/Dr. Norman L. Christensen
Environmental Research Institute of Michigan (ERIM)/Duke University
II. Dr. Frank Davis
University of California, Santa Barbara
Site Description:
The Duke Forest is located immediately west- southwest of Durham, North Carolina. There are 3400 ha within the Duke Forest, 800 of which are old-field loblolly pine stands. The ages of these pine stands range from 1 to greater than 100 years, and represent the successional stages of southern pine species. Numerous ecological studies have been performed on test stands within the Duke Forest, the earliest being in the 1930's. Thus, much of the baseline understanding of ecology of these forests already exists.
The need to develop remote sensing techniques to monitor and study temperate forest ecosystems is especially compelling. The fact that such forests occupy approximately 36 percent of the earth's forested land surface should itself provide sufficient justification for such development. Add to this the fact these forests produce over 75 percent of the forest products (timber and fiber) used by human society, and the social and economic justification for understanding their status and dynamics on a regional and global scale becomes clear.
In addition, temperate forests are especially important in studies of trace gas fluxes from the earth's surface. Most temperate forests have been disturbed to a lesser or greater extent over the past two centuries, and are in various stages of succession. This fact greatly affects their carbon source-sink relationships, and may contribute greatly to fluxes in carbon dioxide. Recent studies (e.g. Tans, et al., 1990) indicate that an understanding of the carbon dynamics of temperate region forests may be crucial to balancing the earth's carbon budget.
Radar remote sensing studies at the Duke Forest began in earnest in 1989, when a comprehensive data set was collected by the NADC/ERIM and the NASA/JPL airborne SARs as part of a three-year study funded by NASA Headquarters. In addition, ground-truth has been collected for some 100 different forest stands to support analysis of the SAR data. Analysis of these data sets is just being completed, and the results are in the process of being published.
The Duke Forest is also a test site being imaged by the ERS-1 SAR, as part of the ESA-sanctioned ERS-1 Forestry Experiment, and JERS-1 SAR, as part of a NASDA-sanctioned JERS-1 Validation Experiment. As part of these studies, a corner reflector array (6 trihedral reflectors) has been deployed in and around Duke Forest, and test sites specifically designed for these experiments are being established. These test sites will be monitored throughout 1992 and 1993. The results of these two research activities will aid in refining the experimental design for the SIR-C/X-SAR Duke Forest Experiment.
Objectives:
The focus of the experiments being conducted at the Duke Forest, North Carolina site is to refine our understanding of microwave scattering from forested terrains, and to develop algorithms to predict aboveground biomass of coniferous forests utilizing spaceborne SAR data.
The Davis and Kasischke studies focus on development of techniques to utilize SAR data in nutrient cycling models for temperate forests in the southeastern U.S. The Kasischke study is focusing on upland forests. These ecosystems process studies will be aided by the theoretical modeling studies of forest structure and biomass being performed in the Davis study. Duke Forest, in the Piedmont region of North Carolina, will also support investigations by Kasischke in his research being conducted as part of the EOS SAR Facility Instrument Team.
Specifically, the following objectives will be addressed:
I. a) Validate a radar tree scattering model using scatterometer and SAR data collected over old-field loblolly pine stands.
b) Determine what short-term physiological changes within loblolly pine forests result in significant changes in radar backscatter signature.
c) Develop a model that predicts the total aboveground biomass as a function of multifrequency, multipolarization radar signature.
d) Evaluate utility of biomass estimation algorithm utilizing SIR-C/X-SAR data set.
II. a) Integrate existing forest biophysical measurements in our Mount Shasta test site with calibrated aircraft SAR for development and testing of our forest radar backscatter model in Ponderosa pine forests.
b) In collaboration with Kaschiske and Christensen, integrate forest biophysical measurements from Duke Experiment Forest and calibrated SIR-C/X-SAR images for model application to loblolly pine forests.
c) Apply model to identify major backscattering components from conifer forests at X-, C-, and L-band and at four polarizations.
d) Develop an algorithm to retrieve forest biomass and structure from SAR images.
Field Measurements:
I. a) Measurement of tree height, diameter, and density for approximately 30 to 40 additional test stands.
b) Measurement of ground and tree moisture and tree water potential for four stands during SIR-C/X-SAR overflights.
c) Monitoring of weather conditions during SIR-C/X-SAR overflights.
d) Deployment and monitoring of calibrated corner reflectors.
II. a) Field data to be collected during the SIR-C/X-SAR missions will include extensive scatterometer and dielectric measurements on individual trees. These data will be incorporated into a scattering model.
Crew Observations:
1) Crew Journal: Describe the weather conditions and forest canopy at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the forests at the site.
Coverage Requirements:
The minimum coverage requirements for this test site are four multiple look angle (4) passes, preferably from the same look direction.
Anticipated Results:
I. a) An understanding of what forest characteristics within a loblolly pine forest influence radar scattering at X-, C- and L-bands.
b) Validation of a theoretical scattering model for the forest geometry of old-field loblolly pines.
c) An evaluation of the utility of multifrequency, multipolarization for estimating aboveground biomass in old-field loblolly pine forests and other pine forests in the southeast U.S.
II. a) Further our understanding of the microwave scattering mechanisms of forests with respect to radar wavelength, polarization, and incidence angle with special emphasis on estimation of above-ground biomass with respect to magnitude, patchiness, partitioning, spatial distribution, and height distribution; and
b) Provide methods to quantitatively estimate biophysical parameters of forest stands from SAR images as input to a spatially-distributed ecosystem model of western pine forests.
References:
Dobson, M.C., F. T. Ulaby, T. LeToan, A. Beaudoin, E. S. Kasischke, and N. L. Christensen, Jr., 1992, Dependence of radar backscatter on coniferous forest biomass, IEEE Trans. Geosci. and Remote Sens., 30: 412-415.
Christensen, N. L., and R. K. Peet, 1981, Secondary Forest Succession on the North Carolina Piedmont, in D.C. West, H.H. Shugart and D.B. Botkin (eds.), Forest Succession: Concepts and Applications, Springer-Verlag, New York, pp. 230-244.
Christensen, N. L., and R. K. Peet, 1984, Convergence during secondary succession, J. Ecol., 72, 25-36.
Kasischke, E.S., and N.L. Christensen, Jr., 1993. Estimation of aboveground, woody plant biomass in loblolly pine forests using multifrequency, multipolarization airborne SAR data. Submitted to IEEE Trans. Geosci. and Rem.Sensing.
Kasischke, E.S., N.L. Christensen, Jr., and E. Haney, 1993. Modeling of geometric properties of loblolly pine tree and stand characteristics for use in radar backscatter models. Submitted to IEEE Trans. Geosci. and Rem. Sensing, inpress.
Kasischke, E.S., N.L. Christensen, Jr., and L.L. Bourgeau-Chavez, 1993. The dependence of radar backscatter on components of biomass in loblolly pine forests. Submitted to IEEE Trans. Geosci. and Rem. Sensing.
Kasischke, E.S., N.L. Christensen, Jr., E. Haney, and L.L. Bourgeau-Chavez, 1993. Observations on the sensitivity of ERS-1 SAR image intensity to changes in aboveground biomass in young loblolly pine forests. Int. J. Remote Sensing, in press.
Kasischke, E. S., and N. L. Christensen, Jr., 1990, Connecting Forest Ecosystem and Microwave Backscatter Models, Int. J. Remote Sens.,11, 1277-1298, .
Peet R. K., and N. L. Christensen, 1980, Succession: A population process in vegetation, 43, 131-140.
Peet, R. K., and N. L. Christensen, 1987, Competition and tree death, Bioscience, 37, pp. 586-599.
Ustin, S. L., C. A. Wessman, B. Curtiss, E. Kasischke, and J. Way, 1992, Opportunities for parameterization of ecosystem models using the EOS imaging spectrometer and synthetic aperture radar, Ecology, (in press).
Titles of Investigations:
I. An Investigation of the Imaging of Ocean Waves and Internal Waves with SIR-C/X-SAR
II. Optimization of SAR Parameters for Ocean Wave Spectra
III. Comparison of SIR-C/X-SAR Simulated and Measured SIR-C/X-SAR Image Spectra with Ocean Wave Spectra Derived from Buoys and Wave Prediction Models
Principal Investigators:
I. Dr. Gordon Keyte
Royal Aerospace Establishment
II. Mr. Frank Monaldo
Applied Physics Lab/Johns Hopkins University
III. Dr. Werner Alpers
Institut fur Meereskunde
Site Description:
The supersite is defined by coordinates 45deg. to 54deg. north and 10deg. to 20deg. west, lying west of the British Isles and the Bay of Biscay and including a section of the European continental shelf break.
The site has been selected to be readily accessible from the European coast and to combine good wave statistics with a useful imaging geometry from ascending and descending SIR-C/X-SAR passes. From studies with the SEASAT radar altimeter and from long-term weather station data, the region has been shown to have a high probability of significant wave heights in excess of two meters. Although more northern sites have even more reliable waves, at latitudes above 54deg., we rapidly lose the scientific benefit of swaths acquired on successive ascending and descending orbits crossing at large angles. At latitudes below 45deg., wave statistics become less dependable for a relatively short duration Shuttle mission. The supersite is also within reception range of European ground stations for "Image Mode" data fro the ERS-1 C-band SAR. This will offer a chance to obtain imagery at very much higher range-to-velocity ratios than are possible with SIR-C.
A successful wave imaging experiment was conducted close to the chosen site as part of the SIR-B mission in 1984. As with that experiment, the in situ data collection will be mobile and will use ship-deployed instrumentation at the positions of SIR-C/X-SAR crossing swaths which will move from day to day during the mission. The selection of experiment sites coincident with pairs of crossing swaths will allow the relatively rapid re-imaging of similar wavefields from different radar illumination directions.
Objectives:
I. a) Improve our understanding of ocean-wave imaging by synthetic-aperture radar (SAR).
b) Test the assumptions of backscattering theory with regard to short-wave properties.
c) Develop new techniques for retrieving ocean-wave spectra from multi-parameter SAR.
II. a) Determine the relative contributions from proposed mechanisms for the imaging of ocean surface waves by SARs.
b) Establish the dependence upon geometry, radar frequency, ocean wave height, and wind speed and direction of the loss of azimuth resolution associated with SAR wave imaging.
c) Select a set of SAR parameters (geometry, frequency, polarization) that maximizes the fidelity of SAR derived, two-dimensional ocean wave spectra in the context of azimuth resolution limits.
III. a) Apply a forecast and hindcast wave prediction model to the wavefields in the North Atlantic from the measured wind history during the SIR-C/X-SAR overflight.
Field Measurements:
The core of the experiment in the East-North Atlantic will be mobile, based around ship-deployed wave and meteorological instrumentation, which will include directional wave buoys. The ship will travel to sites of crossing swaths on successive days at which rapid re-imaging of similar wavefields from different radar look directions will take place. Supporting wave data will come from hindcast modeling.
Crew Observations:
1) Crew Journal: Locate and sketch internal waves. Document ocean state and weather conditions at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph internal waves; low angle sun glint images are requested.
Coverage Requirements:
The minimum requirements for the East-North Atlantic supersite are four (4) crossing tracks.
Anticipated Results:
I. a) An accurate empirical model of the dependence of wave-imaging transfer function on radar frequency, polarization, and incidence angle.
b) A greater understanding of the roles of short-wave straining and of scatterer motions in providing mechanisms for imaging long waves.
c) An improved knowledge of conditions under which non-linear imaging limits the wave information recoverable from SAR data.
d) Optimum procedures for recovering wave information and recommendations for SAR-system parameters for future missions.
II. a) Determination of a composite SAR wave imaging model including the effects of all relevant imaging mechanisms.
b) Determination of whether azimuth resolution degradation is alleviated at higher radar frequencies than L-band.
c) Recommendations for SAR geometry, frequency, and polarization to maximize the fidelity of SAR derived wave spectra and alleviate the loss of azimuth resolution associated with high sea states.
III. a) Determination of the accuracy of the SAR imaging theory for three frequencies through comparison of the measured and predicted ocean wave spectra.
References:
Conway, J.A., R.A. Cordey, and J.T. Macklin, 1991. Modeling of radar backscattering from the sea surface using polarimetric SAR observations. Proc. 5th Int. Colloquium on Physical Measurements and Signatures in Remote Sensing, Courcheval, France, 14-18 Jan. 1991, ESA SP-319, 241-246.
Cordey, R.A., and J.T. Macklin, 1989. Imaging of Ocean Waves by SAR: A Comparison of Results from SEASAT and SIR-B Experiments in the North Atlantic. IEEE Trans. Geosci. and Rem. Sensing,, vol. GE-27, 568-575.
Cordey, R.A., J.T. Macklin, J.-P. Guignard, and E. Oriol-Pibernat, 1989. Theoretical Studies for ERS-1 Wave Mode, ESA Journal, vol. 13, 343-361.
Keyte, G.E., and J.T. Macklin, 1986. SIR-B observations of ocean waves in the N.E. Atlantic. IEEE Trans. Geosci. Remote Sensing,, vol. GE-24, 552-558.
Macklin, J.T., and R.A. Cordey, 1991. SEASAT SAR observations of ocean waves, Int. J. Remote Sensing,, vol. 12, 1723-1740.
Macklin, J. T., and R.A. Cordey, 1989. Ocean wave imaging by synthetic aperture radar: results from the SIR-B experiment in the N.E. Atlantic. IEEE Trans. Geosci. Remote Sensing,, Vol. GE-27, 28-35.
Titles of Investigations:
I. Calibration and Interpretation of Multi-component SAR Imagery for Agricultural and Forestry Applications
II. Multi-Frequency, Multi-Polarization External Calibration of the SIR-C/X-SAR Radars
Principal Investigators:
I. Dr. Ralph Cordey/Dr. Peter Hoogeboom
Marconi Research Centre/TNO Physics and Electronics Laboratory
II. Dr. Anthony Freeman
Jet Propulsion Laboratory
Site Description:
The Flevoland test site is in a polder of 30 by 60 km located in the center of the Netherlands; the polder was reclaimed from a former sea in 1968. The topography is almost perfectly flat, and the general altitude is three meters below sea level. Because of its short history, the landscape of the polder is quite simple, which is an advantage in remote sensing images interpretation. It mainly shows straight roads, farm houses, agricultural fields, forest areas, and only a few urban areas. The forest areas consist of young deciduous trees planted in a regular row pattern. The agricultural fields are cultivated by private as well as state farms. The fields cultivated by state farmers are large compared to fields cultivated by private farmers. The state farms are meant to prepare the "naked sea bottom" for full agricultural use by cultivating them on a non-commercial basis. After this initial phase, the fields will be given to private farmers. By 1996, all fields now owned by the state farms will be divided among private farmers, implying smaller agricultural fields.
The areas of main interest are found in the southern part of the polder. They include an agricultural area and a forested area, each measuring approximately 10 by 10 km. The agricultural area is centered around the coordinates 52.33deg. N and 5.45deg. E and mainly contains fields cultivated by state farmers. The forested area is centered around the coordinates 52.31deg. N and 5.49deg. E.
To compare the results from this typical young forest ("Horsterwold") with an older forest , a second forest site ("Speulderbos") has been chosen on neighboring "old" land. Speulderbos is located on an ice-pushed ridge with an altitude varying from 40 to 55 m above sea level. It is centered around the coordinates 52.16deg. N and 5.67deg. E and contains both deciduous and coniferous trees. The ages of the deciduous trees are up to 150 years old.
The test site has been used extensively since 1984 for various remote sensing experiments and was a part of the SIR-B experiment. More recently, it was used in the Maestro 1989 and the MAC Europe 1991 campaigns, during which it was monitored several times by the NASA/JPL SAR. Three high precision C-band transponders owned by ESA/ESTEC are located in the Flevopolder which are used to calibrate ERS-1 SAR data. As a consequence, the site was (and is) imaged quite often by the ERS-1. For example, the site was imaged every three days in the August-December 1991 period. The JERS-1 imaged the site also regularly in 1993 because of the presence of some L-band transponders.
Objectives:
I. a) Calibration and quality assessment of the SAR data acquired.
b) Determination of crop type classification success with multi-frequency, polarimetric data.
II. a) Assess the accuracy at which the SIR-C/X-SAR standard data products can be calibrated.
b) Study the cross-calibration between three independent multi-polarization systems: SIR-C, the NASA/JPL DC-8 SAR, and the University of Michigan ground-based polarimetric scatterometer.
c) Evaluate the calibration "stability" of the SIR-C/X-SAR.
d) Develop a cost-effective calibration plan which includes development of inexpensive polarimetric active calibrators.
Field Measurements:
Flevoland will be used as a calibration site for the European Remote Sensing experiment (ERS-1). It is likely that corner reflectors deployed for ERS-1 will remain at the site for use by SIR-C/X-SAR calibration.
I. a) Ground truth measurements of miscellaneous soil and crop parameters.
b) Compilation of a crop type map.
c) Deployment of corner reflectors and C- and L-band transponders.
d) An underflight with the Dutch polarimetric C-band SAR system PHARUS will possibly be done.
II. a) Deploy inexpensive trihedral corner reflectors to characterize co-polarized channel imbalance in magnitude and phase over an area wider than that covered by the active calibrators in the primary calibration area.
Crew Observations:
1) Crew Journal: Describe the weather conditions and cloud cover, forest canopy, and agricultural activity at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the forests and agriculture at the site.
Coverage Requirements:
The minimum coverage requirements for this supersite are four (4) passes, preferably <= 48deg.. For the crop type classification experiment it is necessary to acquire data in the May-July time period.
Anticipated Results:
I. a) Insight into the feasibility of crop type classification with multi-frequency, polarimetric data.
b) Calibrated and quality checked SAR dataset.
II. a) Full polarimetric end-to-end characterization of the SIR-C/X-SAR system in the primary calibration target area within the limitations of instrument accuracy.
b) A better understanding of polarimetric calibration of space-borne microwave synthetic aperture radar.
References:
Groot, J. S., A. C. van der Broek and A. Freeman, 1993. An Investigation of 1989 Polarimetric SAR Data for the Flevoland Testsite, EARSEL Advances in Remote Sensing, Vol. 2, No. 1-I.
Freeman, A., J. C. Curlander, F. Heel, M. Zink, P. Hoogeboom, J. Groot, A. Dawkins, J. Baker, M. Reich, and H. Lents, 1990. Preliminary Results of the Multi-sensor, multi-polarization SAR Calibration Experiments in Europe 1989. In Proc. IGARSS '90, Washington, D. C., USA, 783-787.
Freeman, A., J. Villasenor, and J. D. Klein, 1991. Multi-frequency and Polarimetric Radar Backscatter Signatures for Discrimination Between Agricultural Crops at the Flevoland Experimental Test Site. In Proc. of the Third Airborne Synthetic Aperture Radar (AIRSAR) Workshop, May 23-23, 1991, JPL, Pasadena, CA, 44-56.
Freeman, A., J. Villasenor, and J. D. Klein, 1991. Agricultural Crop Discrimination using Multi-Frequency and Polarimetric Radar Backscatter Signatures at the Flevoland Experimental Test Site Proc. of the 3rd AIRSAR Workshop, JPL Publication 91-30.
Groot, J. S., A. C. van den Broek, and A. Freeman, 1993. An Investigation of 1989 Polarimetric SAR Data for the Flevoland Testsite. EARSeL - Advances in Remote Sensing, Microwave Imagery and Related Techniques, 2 (1): 35-40.
Hoogeboom, P., P. Snoeij, P. J. Koomen, and H. Pouwels, 1992. The PHARUS Project, Results of the Definition Study Including the SAR Testbed PHARS. IEEE Trans. Geosci. Rem. Sens., 30, 4, 723-735.
Woode, A. D., Y. L. Desnos, and H. Jackson, 1992. The Development and First Results from the ESTEC ERS-1 Active Radar Calibration Unit. IEEE Trans. Geosci. Rem. Sens., 30, 6, 1122-1130.
Titles of Investigations:
I. The Eruptive Styles of Basaltic Shield Volcanoes from Shuttle Imaging Radar-C (SIR-C) and X-SAR Data
II. Geology of the Galapagos Test Site
III. SIR-C Radar Investigations of Volcanism and Tectonism in the Northern Andes and Galapagos
Principal Investigators:
I. Dr. Peter Mouginis-Mark
University of Hawaii
II. Dr. Pasquale Murino
Istituto U Nobile
III. Dr. Chuck Wood
University of North Dakota
Site Description:
Much remains to be discovered about the volcanoes of the western Galapagos Islands. There are seven shield volcanoes in this area (Fernandina, Ecuador, Wolf, Darwin, Alcedo, Sierra Negra, and Azul) which collectively have erupted more than sixty times this century. Unlike Hawaii, these volcanoes are infrequently studied due to their inaccessibility and delicate ecology. In addition, the rugged terrain, lack of water and field support make these volcanoes difficult to map and study in the field.
Volcanoes in Galapagos are spaced 10-25 km apart, and the stress fields between volcanoes has not influenced the formation of adjacent volcanoes to the extent seen in Hawaiian volcanoes. The identification of proto-rift zones may indicate that the inside of the volcano has preferred lines of weakness that permit easy eruption of lava. These lines of weakness may be influenced by the regional structure of the islands rather than the shape of the individual volcano. The derived radar maps may help us decide between these two models.
The northern flanks of Wolf Volcano, and most of the flanks of Alcedo Volcano, are either covered with vegetation (we are told it's approximately 0.5 m high) or ash deposits (<1 m thick). In Landsat and SPOT data, these areas are bland; however, we see evidence for changes in the location of rift zones on Wolf and, from field work, buried lava flows on Alcedo have been identified and may be visible in radar images. Identification of rift zone location changes would permit the long-term (1,000s to 10,000s of years) evolution of the volcanoes to be determined for the first time.
The flanks of all the volcanoes, but particularly Fernandina, Wolf, and Darwin, are in places very steep (approximately 30-50deg.). Many lava flows descend the slopes of these volcanoes and may show wide variations in lava texture. Such textures are usually used to indicate flow rheology and mass eruption rate (pahoehoe is fluid lava erupted at a low mass eruption rate, a'a is more viscous and has a high mass eruption rate). The calderas of Fernandina, Wolf, Darwin, and Azul volcanoes experience multiple collapse events and produce deep (approximately 1 km) summit craters.
Objectives:
I. a) Study the relative importance of rift zones versus radial fissures in volcano evolution;
b) Verify radar-penetration capability; if verified SIR-C/X-SAR data will permit the regional extent of lava flows to be mapped and the temporal change in vent locations to be identified.
c) Mapping the spatial variability of lava flow types with respect to slope differences will generate new insights into the flow characteristics, as well as show where high volume eruptions occurred.
d) Radar will permit spatter ramparts, fissures, and faults around the summit to be mapped. These maps will enable the structure of the summits to be identified and correlated with areas of recent summit collapse. In turn this will help identify the regional structural characteristics of the volcanoes.
II. a) Evaluate the multiple capabilities of spaceborne SAR in geological and oceanological applications in the Galapagos area.
III. a) Developing radar models for detecting and mapping active volcanoes.
Field Measurements:
Due to the inaccessibility of the Galapagos Islands, field work is not planned in conjunction with the SIR-C/X-SAR mission.
Crew Observations:
1) Crew Journal: Describe volcanic activity at the site and locate other areas where volcanic activity is seen from orbit for future possible data takes. Note variations in albedo when lava flow fields are seen from different angles.
2) Cameras: Linhoff and Hasselblad will be used to photograph the site and other volcanoes visible from orbit at multiple viewing angles. A telephoto lens used with the Hasselblad is also requested. Low sun angle images are needed to see shadows of subtle topographic features on the ground.
Coverage Requirements:
The minimum coverage requirement for the Galapagos is three (3) passes.
Anticipated Results:
I. a) A more complete regional view of the eruptive history will be obtained for seven classic shield volcanoes. This will enable the role of the tectonic setting and spatial variations in activity to be compared using a uniform data set for landforms physically separated by thousands of kilometers which has never before been possible;
b) Develop radar scattering models that enable us to take local test data and extrapolate these observations to the regional scale Such methods are deemed to be particularly important as the geologic community prepares not only to study geographically isolated terrestrial landforms using ERS-1, JERS-1, and EOS data sets, but also to analyze planetary volcanic terrains such as those on Venus (imaged by NASA's Magellan spacecraft).
II. a) To update structural and hydrogeological maps by regional reconstruction of the structural and volcano-tectonics setting and its correlation with plate-tectonics and earthquakes epicenters.
III. a) Greatly improve geologic knowledge of poorly mapped, frequently cloud-covered, volcanically active arc.
b) Develop an optimal interpretation of radar data for detection and mapping of pyroclastic/ lahar deposits in tropical environments.
c) Improve understanding of distribution and character of poorly mapped deposits at the Galapagos volcanoes.
References:
Chadwick, W. W., and K. A. Howard, 1991, The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela Islands, Galapagos, Bulletin Volcanology, 53, 259-275.
McBirney, A. R., and H. Williams, 1969, Geology and petrology the Galapagos Islands, Geological Society of America Memoir, 118, 197 pp.
Nordlie, B. E., 1973, Morphology and structure of the Western Galapagos volcanoes and a model for their origin, Geol. Soc. of Am. Bulletin, 84, 2931-2956.
Simkin, T., and K. A. Howard, 1970, Caldera collapse in the Galapagos Islands, Science, 169, 429-437.
Titles of Investigations:
I. U. S. Navy Investigations to be Conducted During the SIR-C/X-SAR Experiment
Principal Investigators:
I. Dr. Donald Montgomery
U. S. Naval Observatory
II. Mr. Robert Beal
Applied Physics Lab/Johns Hopkins University
Site Description:
The Gulf Stream Supersite is located within corners (42deg.N, 75deg.W), (36deg.N, 65deg.W), (30deg.N, 73deg.W), with nominal center at 36deg.N, 73deg.W. This is an ideal site because of its convenient location adjacent to the East Coast of the U. S. and the ease of deploying buoys, ships, and aircraft to support high quality sea-truth and calibration for the SIR-C/X-SAR passes in 1993-1996. Such support includes USNS Ago ships and Naval Research Laboratory (NRL) and NAWC/P-3 aircraft.
Gulf Stream dynamics in this area have been intensively investigated and modeled over the years by the U. S. Navy, other government agencies (i.e., NOAA, NASA, EPA, NSF), and a number of academic institutions (i.e. University of Rhode Island, Harvard University, Woods Hole Oceanographic Institution, Johns Hopkins University). Models have reached an advanced state and can be used in remote sensing investigations on current-wave interactions with synthetic aperture radar (SAR), with SIR-C/X-SAR L-, C-, and X-band data, and from other present and future spaceborne SAR systems such as ERS-1, JERS-1, ERS-2, ALMAZ, RADARSAT, and EOS.
The Gulf Stream is a natural laboratory with a variety of oceanic features of basic and applied research interest. These features include: internal waves, fronts, rips, mesoscale eddies, and others which are continuously shed by Gulf Stream meanders. "Slick-like" and bathymetry-related surface features are also abundant over the continental shelf at the site. The U. S. Navy and NRL have a number of projects addressing scientific and applied research relating to the Gulf Stream. For example, the Office of Navy Research (ONR) and the NRL have a five year ARI on High Resolution Remote Sensing ('91-'95) in the Gulf Stream region for understanding radar imaging of submesoscale oceanic features. The first experiment in this program was performed in September 1991 and a second field experiment is planned for July-September 1993. Preliminary experiments were conducted during 17-21 July 1990 and 2-4 October 1990.
The Department of the Interior Mineral Management Service also has a comprehensive three-year program starting in 1992 to understand the oceanography of Cape Hatteras out to 200 km east of the Cape. The program involves measurements and modeling that should provide additional sea-truth from buoys and ships. Hence, extensive buoy, ship, and aircraft support will be available during the SIR-C/X-SAR mission for sea-truth and calibration.
Objectives:
I. a) The general objectives of the U. S. Navy SIR-C/X-SAR program is to provide data for verifying SAR performance models for measurement of oceanic processes; contribute to the detailed knowledge of aircraft and satellite SAR as a function of frequency, incidence angle, aspect angle, sampling/integration time, other system parameters; and support existing research programs in descriptive and physical oceanography.
b) Specific scientific investigations to be conducted include: radar imaging of submesoscale oceanic features, refraction of waves by variable currents, the perturbation of ship wakes by currents and the origin of "slick-like" features.
c) SIR-C/X-SAR PIs from several institutions, including NRL, ONR, NSWC, JHU/APL, NAWC, University of Southern Mississippi, and JPL, are interested in performing scientific and applied research in Gulf Stream Supersite . These investigators include: G. R. Valenzuela, S. A. Mango, R. P. Mied, A. R. Ochadlick, W. C. Keller, O. H. Shemdin, R. Beal, F. Monaldo, D. Sheres, P. M. Smith, R. C. Bachman, F. Herr, C. Luther, and R. Goldstein. Others are welcome to participate in the research as well.
Field Measurements:
The exact plan for operations and deployment of ground/sea truth instruments during SIR-C/X-SAR passes at Gulf Stream Supersite is dependent on the resources and funding, the amount of which is presently not known. In the meantime, we can state that high quality ground/sea truth will be provided at the Gulf Stream Supersite from at least one dedicated Navy AGOR oceanographic ship, two Navy airplanes, and a number of National Data Buoy Center (NDBC) buoys which are permanently deployed for the National Weather Service (NWS) off the East Coast of the U. S. Furthermore, the Minerals Management Service of the U. S. Department of the Interior has a comprehensive field and modeling program that should provide valuable data out to 200 km from the coast from moored buoys, ARGOS drifters, and ship surveys.
Specific resources that should be available during the SIR-C/X-SAR passes in October 1993 are:
USNS Bartlett (Oceanographic Ship) Std. meteorological/oceanographic measurements
ADCP (Acoustic Doppler Current Profiler)
CTD/XBTs
Directional Wave Buoy (0.04-0.40 Hz)
Spar Buoy (1 m - 10 cm waves)
Lagrangian drifters
Surface tension
NRL/P-3 Aircraft C- and X-band Real Aperture Radar (RAR)
Ku-band scatterometer
PRT-5 infrared thermometer
Laser profilometer
Multi-spectral video camera
Ku-band Radar Ocean Wave Spectrometer (ROWS)
NAWC/P-3 Aircraft L-, C- , X-band SAR w/ Polarimetric & Spot-light modes
X-Band Interferometric SAR (DPCA)
GPS Navigation
NDBC Buoys (NOAA) CHL V2 (36.9deg.N, 75.7deg.W) (C-Man Station)
41001 (34.9deg.N, 73.0deg.W) (moored)
44004 (38.5deg.N, 70.7deg.W) (moored)
44014 (36.6deg.N, 74.8deg.W) (moored)
44009 (38.4deg.N, 74.7deg.W) (not permanent)
44012 (38.8deg.N, 74.6deg.W) (not permanent)
Other resources include:
NRL (Code 4230) Digital Image Processing Laboratory (DIPL)
End-to-End SAR processing facility
Extensive Spaceborne/Airborne Data Base
SAR Communications System Real Time System
NAWC (Code 5024) SAR Data Digital Processing Laboratory
Corner Reflectors for SAR calibration
NSWC (Carderock Division) Endeco buoy, directional wave analysis with Maximum Likelihood, Maximum Entropy methods, and Wavelet techniques.
Ship motion sensors, data collection and analysis
Potential GPS, position and velocity inferred
Minerals Management Service/Atlantic OCS Region
Extensive field data from 14 moored buoys, ARGOS drifters, and ship hydrographic surveys for three month periods starting in February 1992 and continuing through 1994 in a region included between 73.5deg.W and the coast of Cape Hatteras within latitudes 36.5deg.N and 34.5deg.N.
Crew Observations:
1) Crew Journal: Document and locate storm activity, current boundaries, and internal waves.
2) Cameras: Linhoff and Hasselblad will be used to photograph storms, current boundaries, and waves. Low angle sun glint images are requested.
Coverage Requirements:
The minimum coverage requirements for the Gulf Stream are four (4) passes.
Anticipated Results:
I. These investigations will employ a variety of technical approaches, combining SIR-C/X-SAR data with intensive, fine-scale in situ measurements and aircraft-derived data and will contribute to:
a) New and/or improved models describing the mechanisms involved in SAR imaging of ocean features and improved definition of the limits of applicability of SAR in a maritime environment.
b) An improved understanding of how current boundaries are imaged with SAR and of the detectability criteria for current boundaries.
c) Advances in the understanding of major physical mechanisms driving the generation, propagation, and dissipation of ocean phenomena, such as swell, internal waves, and near surface fine-scale features.
d) Compilation of SAR images and ship wake characteristics correlated with radar, ship, and meteorological parameters.
e) Improved understanding of the mechanisms responsible for SAR imaging of wake characteristics at L, C, and X-band radar frequencies in different sea states.
f) Evaluation of SAR's potential use in synoptic detection/observation/monitoring.
References:
Beal, R. C., F. M. Monaldo, and D. G. Tilley, 1983. Large and small scale spatial evolution of digitally processed ocean wave spectra from the Seasat synthetic aperture radar, J. Geophys. Res., 88, 1761-1778.
Beal, R. C., T. W. Gerling, D. E. Irvine, F. M. Monaldo, and D. G. Tilley, 1986, Spatial variations of ocean wave directional spectra from the Seasat synthetic aperture radar, J. Geophys. Res., 81, 2433-2449.
Gerling, T. W. , 1986, Structure of the surface wind field from the Seasat SAR, J. Geophys. Res., 91, No. C2, 2308-2320.
Hayes, R. M., 1981. Detection of the Gulf Stream. Spaceborne Synthetic Aperture Radar for Oceanography, edited by R. C. Beal, P. S. DeLeonibus, and I. Katz. Johns Hopkins University Press.
Larson, T. R., Moskowitz, L. I., and Wright, J. W., 1976, A note on SAR imagery of the ocean, IEEE Trans. Antennas Prog., AP-24, 393-394.
Liu, A. K., F. C. Jackson, A. E. Walsh, and C. Y. Peng, 1989, A case study of wave-current interaction near an oceanic front, J. of Geophys. Res., 16189-16200.
Sheres, D., K. E. Kenyon, R. L. Bernstein, and R. C. Beardsley, 1985. Large horizontal surface velocity shears in the ocean obtained from images of refracting swell and in situ moored current data. J. Geophys. Res., 90, No. C3, 4943-4950.
Titles of Investigations
I. The Evaluation of SIR-C/X-SAR Imagery for Surficial Sediment Mapping and Groundwater Management in Australia
II. Climate Change and Neotectonic History of Arid/Semi-arid Regions
III. Multi-Frequency, Multi-Polarization External Calibration of the SIR-C/X-SAR Radars
IV. Alluvial Fan Evolution
V. Combined Altimetry and SAR Imagery of a Desert Test Site
Principal Investigators
I. Dr. Geoffrey Taylor
University of New South Wales
II. Dr. Anthony Freeman
Jet Propulsion Laboratory
III. Dr. Tom Farr
Jet Propulsion Laboratory
IV. Dr. Allan Gillespie
University of Washington
V. Dr. Chris Rapley
University College London
Site Description:
The Kerang region of Australia is part of the lower Loddon Valley which merges into the southern side of the Murray Valley, located some 500 km west of Canberra. The terrain is remarkable for its flatness, falling gently to the north, and is mostly divided into large agricultural fields. The Kerang region produces food, fiber, and fodder and serves as a valuable source of livestock. Agriculture away from the immediate vicinity of the river channels is dependent on irrigation. The wetlands in the river valleys support wildlife and recreation areas.
The Murray basin is a Cenozoic sedimentary basin with over 300 meters of marine and lacustrine sediments. The region around Kerang is characterized by aeolian and lacustrine sands, the latter showing numerous prior stream courses. There are numerous natural ground water discharge areas in the Kerang region and irrigation has raised the water table in adjacent regions, resulting in salinization of upper soil horizons. The salts are derived from "ancient" saline ground water at depth rather than from the present day Murray river. Better irrigation practices can minimize the salinization problem but require the ability to recognize the presence of elevated water tables at an early stage.
Because of the flatness, the region is suitable as a primary calibration site for SIR-C/X-SAR. To support this effort, Australian scientists and engineers have offered to supply, deploy, and operate calibration equipment in the Kerang region. In addition, other important SIR-C/X-SAR objectives of this experiment are to determine the utility of SAR images to map surficial sediments and to map elevated water tables and saline soils to allow for better control of the salinity problem.
Objectives:
I. a) Assess the utility of multi-polarization, multi-frequency spaceborne radar for surficial sediment mapping and ground water management in a variety of Australian environments.
b) Establish the utility of the SIR-C/X-SAR imagery for recognizing basement structures.
II. a) Assess the accuracy at which the SIR-C/X-SAR standard data products can be calibrated.
b) Study the cross-calibration between three independent multi-polarization systems: SIR-C, the NASA/JPL DC-8 SAR, and the University of Michigan ground-based polarimetric scatterometer.
c) Evaluate the calibration "stability" of the SIR-C/X-SAR.
d) Develop a cost-effective calibration plan which includes the development of inexpensive polarimetric active calibrators.
III. a) The goal of the proposed research is to determine the history of Quaternary climate change for inclusion in global paleoclimate models and reconstructions of the tectonic history of the area.
IV. a) Describe systematic morphologic changes with surface age in terms of multiparameter radar backscatter.
b) Construct for the studied fans a depositional and weathering history based on SAR and other images and field investigations.
c) Use the depositional and weathering history of the study area to constrain paleoclimatic interpretations.
d) Use project as prototype for paleoclimate studies.
e) Test the hypothesis that spectral mixing analysis can be applied to multiparameter SAR images of alluvial fans in arid and semiarid regions.
f) Define radar endmembers physically, in terms of Bragg scattering, volume scattering, specular and corner reflectors, and dielectric constant, etc..
g) Develop and test mixing models for comparative analysis of images spanning multiple spectral regions.
V. a) Carry out a technical and geophysical investigation of scanning-beam, beam-limited altimetry using SIR-C/X-SAR at vertical incidence over a well-characterized desert test site.
b) Evaluate and compare the height information obtainable by means of SAR-interferometry and SAR-stereo over the selected desert test site.
c) Investigate desert surface and subsurface features and properties which can be measured, and to define optimum observing parameters.
d) Evaluate the role of satellite remote sensing in geomorphological processes of erosion, transportation, and deposition in arid regions.
e) Develop and validate analysis techniques for the study and monitoring of desert processes.
Field Measurements:
I. a) A record of the recent history of borehole water tables, soil moisture contents, chemical composition, field determined dielectric properties, and visible, near, and mid-IR signatures is currently being acquired. At the time of the overpasses, surveys will be made of the following parameters:
* soil moisture/chemical composition/dielectric properties;
* water tables and recharge rates in boreholes;
* ground and air temperatures;
* soil resitivities; and
* vegetation cover and vigor
b) As near as possible to the mission, it is planned to acquire coincident GEOSCAN imagery (including the near and mid-infrared) and Landsat Thematic Mapper imagery. It is also planned to execute a penetration experiment using buried targets. The construction of L-band corner reflectors and PARCs for the Kerang array is currently near completion.
II. a) Deploy inexpensive trihedral corner reflectors to characterize co-polarized channel imbalance in magnitude and phase over an area wider than that covered by the active calibrators in the primary calibration area.
Crew Observations:
1) Crew Journal: Describe weather conditions and cloud cover, aeolian activity, saline soils and surficial sediment, high water tables, and amount of vegetation at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the site.
Coverage Requirements:
The minimum coverage requirements for the Kerang, Australia test site are four (4) passes, preferably <=48deg..
Anticipated Results:
I. a) Be able to map surficial deposits of different type and age by surface roughness, sub-surface volume scattering, cross-polarization returns and phase difference images. This will have important consequences for the recognition of potential aquifer materials in arid and semi-arid regions.
b) Be able to map seepage zones in areas of internal drainage and salt-lake formation by using variations in dielectric constant to determine moisture contents and conducting salt layers. This will be important in the understanding of natural salt-lake systems and in salinity management in irrigation areas such as the Murray Darling Basin and elsewhere in the world.
c) Demonstrate that spaceborne radar will be a powerful tool for mapping basement tectonic features through overlying surficial sediments. While having undoubted implications for petroleum exploration, this will also be important for recognizing high permeability zones for the siting of water bores.
d) Test the effect of varying amounts of vegetation cover on our ability to achieve (a), (b), and (c).
II. a) Full polarimetric end-to-end characterization of the SIR-C/X-SAR system in the primary calibration target area within the limitations of instrument accuracy.
b) A better understanding of polarimetric calibration of space-borne microwave synthetic aperture radar.
III. a) Maps of geomorphic surfaces with ages attached to them will be a major step toward understanding the climatic history of this region of the earth.
b) Comparisons of this climate record with climate records from the oceans and other continents will help advance the global synthesis of climate change.
c) Answers to the questions of how unique and how globally representative remote sensing signatures are will directly affect our future ability to extrapolate the signatures to global studies of climate change.
d) Determination of past slip rates on some active faults in the area by knowing the ages of offset surfaces.
IV. a) New technique for "unmixing" multiparameter radar images into meaningful components (e.g., volume-scattering surfaces or "vegetation", Bragg-scattering surfaces, etc.).
b) An alternative to "extended spectral signatures" for joint analysis of disparate images spanning multiple spectral regions.
c) Better history of bajada surface evolution than available from chemical weathering studies alone.
d) Test of predictive models for climate/paleoclimate and for inferences from paleoecological studies.
V. a) A demonstration of scanned-beam, beam-limited altimetry and along-track synthetic aperture processing resulting in an improved specification for future instruments.
b) Improved understanding of the radar backscatter mechanism from homogeneous, rough surfaces, particularly at vertical incidence.
c) A quantitative assessment of SAR-interferometric and SAR-stereo height estimation.
d) An improved understanding of the information content of SAR imagery of arid regions, and the specification of optimum observing parameters for desert imagery.
e) The development of an improved DTM for the desert test site, including topography and surface/subsurface characteristics such as surface roughness, soil type, moisture content and vegetation cover.
f) The development and validation of analysis techniques and observing methodologies for the determination and monitoring of desert morphological processes, particularly those related to climate change.
References:
Butler, B.E., G. Blackburn, J.M. Bowler, C.R. Lawrence, J.W. Newell, and S. Pels, 1973. A geomorphic map of the riverine plain of south eastern Australia. Australian National University Press, Canberra, 39 pp.
Jankowski, J. and I. Acworth, 1992. Process of salinization: mixing of deep and shallow ground waters and water-rock interaction, a case study from the southern tablelands, NSW. Proc. 3rd Murray Basin Groundwater Workshop, Renmark, in press.
Lynne, G.J. and G.R. Taylor, 1986. Geological assessment of SIR-B imagery of the Amadeus Basin, Central Australia. Trans. IEEE Geosci. and Remote Sensing, GEO24, 4, 575-581.
Mah, A. and G.R. Taylor, 1992. Probing the dryland salinity problem with a L-band portable dielectric probe. Proc. Radar Rem. Sens. Conf., Adelaide, 11 pp.
Shettigara, K.V. and J.A. Odins, 1987. Application of NOAA-VHRR images for structural studies related to groundwater flow in the Murray Darling Basin. Proc. 4th Aust. Rem. Sens. Conf., Adelaide, 724-734.
Taylor, G.R., 1992. Image processing of structural data for mineral exploration. extd. abstract, Metals and Exploration Towards 2000, Sydney University.
Taylor, G.R., and Moseley, N.R., 1991. Geological mapping in the Camel Flat Allambi region with the NS001 airborne scanner; in Geological and Geophysical Studies of the Amadeus Basin, central Australia. Ed. R.J. Korsch, B.M.R. Bulletin, 236, 59-66.
Taylor, G.R., 1990. The geological information content within Landsat Thematic Mapper images. Proc. 5th Aust. Rem. Sens. Conf., Perth, 675-678.
Taylor, G.R., 1988. Image analysis techniques for the interpretation of air photo lineaments-petroleum exploration, Eromanga Basin, Australia. Geocarto International, 3, 53-60.
Taylor, G.R. and Lynne, G.J., 1987. Airborne scanners for stratigraphic mapping in the Amadeus Basin, N.T., Proc. 4th Aust. Rem. Sens. Conf., Adelaide, 387-386.
Titles of Investigation:
I. Determining the Extent of Inundation on Subtropical and Tropical River Floodplains Beneath Vegetation of Varying Types and Densities
II. Global Biodiversity: Assessment of Habitat Change and Species Extinctions with Multiparameter Synthetic Aperture Radar (SAR) Data
III. Information Extraction from Shuttle Radar Images for Forest Applications
IV. Relating Radar Backscatter Responses to Woody and Foliar Biomass of Forests
V. Inflight Antenna Pattern Measurement for SIR-C
Principal Investigators:
I. Dr. John Melack
University of California - Santa Barbara
II. Dr. Jack Paris
California State University - Fresno
III. Dr. Rudolf Winter
DLR
IV. Dr. Thuy LeToan
Centre d'Etudes Spatiales des Rayonnements
V. Dr. Richard Moore
University of Kansas
Site Description:
The Amazon and its floodplain is the world's largest river system, draining 37% of South America and discharging about 20% of the freshwater reaching the world's oceans. Bordering the middle reach of the river is a very large floodplain with thousands of lakes - a freshwater habitat with exceptional biological diversity and increasing economic importance. The dominant seasonal pattern in the central Amazon basin is a ten-meter rise and fall of river level. As the waters rise, a mosaic of flooded forests, floating grasses, and open water forms on the floodplain, which functions as a capacitor and reaction vessel for the energy and nutrient fluxes that sustain its fertility. Recent attempts to model the carbon biogeochemistry of large tropical rivers have shown that the fluxes between the floodplain and river are likely to be significant. The mosaic of flooded forest, lakes, and floating macrophytes in the central Amazon floodplain makes a significant contribution to tropospheric methane. The fishery potential of large rive4rs is closely tied to the area of floodplain and the magnitude and duration of inundation. The majority of fishes harvested in the Amazon basin obtain nutrition in flooded forests or from organic matter derived from floodplain phytoplankton.
Manaus lies at the confluence of the Solimões and Negro rivers, which combine to form the Amazon River. The Solimões River is rich in dissolved nutrients and suspended sediments and has extensive, fertile floodplains. A hydrologically and geomorphologically defined floodplain reach is located about 150 km west of Manaus; the largest lake in the reach is called Cabaliana, hence this section is referred to as the Cabliana floodplain. The Negro River is nutrient-poor and contains high concentrations of dissolved organic carbon, hence it is called a black water river. About 100 km from Manaus, a large, forested archipelago (Anavilhanas) bagins and extends another 100 km upriver.
Objectives:
I. a) Develop a procedure for recovering the presence, absence, and patchy presence of water and its spatial distribution under diverse types of vegetation canopies.
b) Modify, extend, and verify the Santa Barbara vegetation radar model for different floodplain vegetation types and densities.
c) Couple the above modeling and discrimination procedures for floodwater detection and delineation for input to conceptual flood stage/flood area hydrologic models.
II. a) Study the impact of tropical forest fragmentation on the populations of endangered and threatened species of certain mammals, butterflies, birds, and plants in these habitats.
b) Evaluate the use of the unique information about forest distributions and stand conditions expected from multiparameter synthetic aperture radar (SAR) relative to that from the MSS and AVHRR.
III. a) Extract all possible information from shuttle-borne radar images for areas with forest stands.
IV. a) Demonstrate the use of spaceborne SAR images to detect forest parameters.
b) Increase our understanding of the interaction between microwave and vegetation canopies.
V. a) Obtain vertical antenna patterns of the SIR-C/X-SAR radars to allow improved radiometric calibration of data for other investigations.
b) Determine how much the vertical antenna pattern changes after launch.
Field Measurements:
I. a) Low level overflights and ground surveys to determine extent of inundation.
b) Measure characteristics of vegetation required for radar models, i.e., number of trees of various sizes per ha, tree diameters, crown thicknesses, branch sizes, leaf area, dielectric constant.
II. a) Field data will be collected on the response of subject species to habitat fragmentation.
III. a) Classification results will be based mainly on SAR information, however, non-satellite data (air photos, soil maps, forest maps, and ground truth) will be used as reference data and to verify the results.
Crew Observations:
1) Crew Journal: Document state of forest and agricultural areas and note any burning activities or smoke near the site. Describe cloud cover, cloud types, and the presence of any rain clouds. Note any clearcut extent at the site. Note sunglint under forest as evidence for inundation.
2) Cameras: Linhoff and Hassleblad will be used to acquire color and infrared photos of clouds and wetlands, and stereo photos of forests.
Coverage Requirements:
The minimum coverage requirements for the Manaus, Brazil test site are four (4) ascending or four (4) descending passes.
Anticipated Results:
I. a) Improve the monitoring of wetland hydrological regimes.
b) Provide a quantitative assessment of the accuracies of radar floodwater mapping beneath dense vegetation canopies.
c) Use our backscatter model and field data to isolate unique SAR backscatter signatures for changes in wetland inundation and soil moisture.
II. a) Provide valuable, relatively high spatial resolution information about forest fragmentation conditions for use in refining such estimates based on MSS and AVHRR data.
b) Provide valuable insight into the extended and broader area usage of spacecraft SAR data (e.g., from the EOS SAR) for studies of tropical forest type classification, biodiversity, and species loss in future years (i.e., during the EOS era).
c) Promote the use of remotely-sensed data for the study of an important ecological issue -- the impact of cultural activities on forest habitats and on the threatened and endangered species that reside in these.
III. a) Differentiation of forested and non-forested areas with an assessment of the accuracy of separation.
b) Information on the tree stand geometry, age classes of trees, and seasonal changes.
IV. a) Demonstration of the use of multifrequency, multipolarization and multi-incidence SIR-C/X-SAR data to probe different parts of a forest canopy.
V. a) Improve on antenna patterns produced preflight.
b) Measure change in the antenna pattern between ground and space conditions.
References:
Hess, L.L., J.M. Melack, and D.S. Simonett, 1990. Radar detection of flooding beneath the forest canopy: a review. Int. J. Remote Sensing, 11(7), 1313-25.
Hess, L.L. and J.M. Melack, 1992. Strategies for detection of floodplain inundation with multi-frequency polarimetric SAR. Summaries of the Third Annual JPL Airborne Geosci. Workshop, June 1-5, 1992, Vol. 3: AIRSAR Workshop (Pasadena, CA.: Jet Propulsion Lab).
Melack, J. M., L. L. Hess, and S. Sippel, 1994. Remote sensing of lakes and floodplains in the Amazon Basin. Remote Sensing Reviews (in press).
Richey, J. E., J. B. Adams, and R. L. Victoria, 1990. Synoptic-scale hydrological and biogeochemical cycles in the Amazon River basin: a modeling and remote sensing perspective. In R. J. Hobbs and H. A. Mooney, eds., Remote sensing of biosphere functioning (New York: Springer-Verlag).
Titles of Investigations:
I. Contribution of SAR for Estimating Soil Erosion
II. Test of Roughness and Moisture Algorithms Using Multiparameter Spaceborne SAR and Application to Surface Hydrology
Principal Investigators:
I. Dr. Paolo Canuti
University of Florence
II. Dr. Daniel Vidal-Madjar
CNET/CRPE
Site Description:
The test site at Montespertoli is representative of the Thyrrenian slope of Apennines. Bedrock in the area is comprised of Pliocene marine and lacustrine sediments and is intensively affected by erosion and mass movements. More than half the site area is hilly (average height of about 250 m), with agricultural fields and little urbanization. In the past 20 years, the hillsides have been extensively altered to make vineyards accessible to mechanized farm equipment that requires slope uniformity. The northern part of the area is characterized by the flat alluvial wetlands of the Arno River, agricultural fields (colza, corn, sunflower, sugarbeet, and reed), and urbanization. The average field dimensions are about 4-5 ha. Hillsides in the southern part of the area is occupied by croplands (mostly vineyards, oliveyards, wheat, and grass) and woodlands. The average annual rainfall is 904 mm, and the average air temperature is 15deg.C.
Objectives:
I. a) Evaluate SAR potential in the study of soil erosion problems.
b) Investigate the contributions of SAR images in reconstructing different stages of transport and redeposition of material on watershed slopes, using models which take into consideration several parameters of soil surface (moisture content, roughness, vegetation cover, etc.) that can be extracted from radar backscattering.
II. a) Evaluate the usefulness of radar-derived parameters in surface hydrology.
b) Demonstrate the usefulness of the squint mode in the case of bare soil observations.
c) Compare various roughness/moisture algorithms in a real space imaging mode.
Field Measurements:
I. a) During the SIR-C/X-SAR experiment, the ground truth parameters listed below will be measured in the two sub-areas of the test site chosen for detailed experiments (Pesa Virginio).
Soil
* soil moisture content (gravimetric and volumetric) at different depths (5.0, 10.0, and 20.0 cm) using a hand augers and in different parts of each field;
* dielectric constant of soils using dielectric probes at different frequencies;
* surface soil roughness, expressed as standard deviation of the heights (hstd) and correlation length (lc); and
* soil temperature at [[ordfeminine]] 5 cm by a thermometric probe.
Vegetation
* crop classification (crop type, variety);
* sowing date, phenological stage of plants, crop conditions, % weed cover;
* height and density of plants;
* number and dimension (length and width) of leaves, diameter of stems;
* leaf area index (m2/m2); and
* plant water content (computed as the difference between fresh and dry weight; kg/m2) of different plant constituents (leaves, stems, ears, etc.).
b) Selected parameters (soil moisture, crop classification, phenological stage, plant height and width) will be measured over the whole area. In addition, sediment transport will be measured at a station on the Virginio stream, along with stream and rainfall measurements. Texture, as well as other soil characteristics have already been determined. A DTM has been prepared for some areas of Pesa and Virginio basins (Cerbaia and Lucardo zones). Some meterological data (air temperature and humidity, rainfall) are available from three meterological stations in the area.
II. a) The proposal is based on comparison between radar observation and well documented ground truth within a watershed.
b) The radar data will be compared to ground data using existing surface/wave interaction models.
c) An airborne dual frequency (C and X) multipolarization scatterometer will be used to calibrate radar data and to complete the data set (in view angle).
Crew Observations:
1) Crew Journal: Describe weather conditions and vegetation at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the vegetation at the site.
Coverage Requirements:
The minimum coverage requirements for the Montespertoli test site are one (1) early pass and one (1) late pass.
Anticipated Results:
I. a) Quantitative assessment of the relative contribution of soil and different types of vegetation to the backscattering coefficient.
b) Map geological and erosional features from radar images.
c) Estimate geophysical parameters which are involved in the hydrological cycle (soil moisture, soil surface roughness, vegetation biomass, etc.).
d) Test and validate models to describe soil erosion processes at basin scale which can use SAR data as inputs.
II. a) Calibration of the shuttle radars over distributed targets.
b) Test of multi-incidence angle algorithms using squint mode SAR and test of roughness/moisture algorithms.
c) Evaluation of radar images in surface hydrology.
References:
Alparone, L., S. Baronti, C. Carla, and C. Puglisi, 1992. A new adaptive filter for SAR images: preliminary evaluation in land and crop classification on Montespertoli area. Proc. IGARSS, 1992.
Bechini, C., P. Canuti, S. Moretti, S. Paloscia, and P. Pampaloni, 1991. Microwave remote sensing for hydrological and agricultural Monitoring. Proc. of 24th Intl. Symp. on Remote Sens. of Environment (ERIM), 27-31 May, 1991.
Bechini, C., L. Chiarantini, P. Ciotti, S. Moretti, E. Pettinelli, and N. Pierdicca, 1992. MAC-91 on Montespertoli: preliminary assessment of land polarimetric features. Proc. IGARSS, 1992.
Canuti, P., D'Auria, G., Pampaloni, P. and Solimini D., 1992. MAC-91: an experiment for agrohydrology. Proc. IGARSS, 1992.
Canuti, P., L. Chiarantini, and S. Moretti, 1989. Applications of multifrequency (MF) SAR images in hydrology. Symp. on applications of multifrequency/multipolarization SAR in view of X-EOS (X-SAR for EOS) CGS, Matera: June 26-27, 1989. H. Öttl, P. Pampaloni, et al., Eds. DLR-Mitt. 90-12, 77-94.
Chiarantini, L., P. Coppo, G. Luzi, P. Canuti, S. Moretti, S. Paloscia, and P. Pampaloni, 1989. A contribution of microwave remote sensing for soil erosion forecasting. 7th Thematic Conf. on Remote Sensing for Exploration Geology, ERIM.
Coppo, P., P. Ferrazzoli, G. Luzi, S. Paloscia, G. Schiavon, and C., 1992. MAC-91 on Montespertoli: preliminary analysis of multifrequency SAR sensitivity to soil and vegetation parameters. Proc. IGARSS, 1992.
Titles of Investigations:
I. X-SAR/SIR-C Radiometric Calibration Experiment
II. Information Extraction from Shuttle Radar Images for Forest Applications
III. Multi-Frequency, Multi-Polarization External Calibration of the SIR-C/X-SAR Radars
Principal Investigators:
I. Dr. Franz Heel
DLR
II. Dr. Rudolf Winter
DLR
III. Dr. Anthony Freeman
Jet Propulsion Laboratory
Site Description:
The SIR-C/X-SAR supersite at Oberpfaffenhofen, Germany, near Munich, is centered at the Oberpfaffenhofen DLR area (48.09deg. latitude, 11.29deg. longitude). DLR has good communication facilities, numerous processors, laboratories, and the technical/technological infrastructure to support sophisticated calibration experiments in the area. Therefore, a couple of years ago, we selected this area as a calibration test site. Additionally, due to site characteristics such as agricultural fields, grassland, forests, cities, and lakes, scientists from other institutions will use this test site for land use experiments. Land use studies are predominantly focused on agricultural, forest, and hydrological investigations.
To meet mission conditions for SIR-C/X-SAR, ERS-1, JERS-1, and PRIRODA, the test site area will be extended up to about 10,000 km2.
In August 1989, the first DC-8/E-SAR airborne SAR campaign took place at the Oberpfaffenhofen test site. For calibration purposes, forty-two trihedral and four dihedral corner reflectors, one C-band ARC and one C-band receiver prototype were deployed within the SAR swaths. Both SAR systems were operated at three different incidence angles (30deg., 45deg., 55deg.), requiring realignment of all the calibration devices after each flight path. Additionally, ground truth measurements were conducted during the SAR campaign. Our calibration analyses covered all the main measurement objectives including absolute, polarimetric, cross-track, and cross-sensor calibration. Another team is correcting for geometrical distortions to obtain geocoded SAR images.
Calibration activities continued during the second DC-8/E-SAR campaign (July 1991) at this site. In addition, a first attempt was made at determining the cross-track inflight antenna pattern. For this purpose, eighteen C-band receivers and nine C-band ARCs with receiving paths were located across track within the -10 dB points covering a distance of about 35 km. A GPS receiver was used to survey the ground receivers and to synchronize their internal clocks. The procedure applied to the receiver data was successful in obtaining the desired cross-track inflight antenna pattern. Antenna squint angle, as well as misalignment between A and V patterns and pulse shapes, could also be determined by this method. During this campaign, ground truth measurements included documenting plant geometry, moisture content, biomass, and forest stand determination.
For spaceborne SAR missions like SIR-C/X-SAR, X-band and L-band receivers and ARCs will be deployed. This equipment includes twenty receivers and five ARCs for each frequency band.
Objectives:
I. a) Determine error sources and their relative contributions to the absolute calibration accuracy of the overall system.
II. a) Extract all possible information from shuttle-borne radar images for areas with forest stands.
III. a) Assess the accuracy at which the SIR-C/X-SAR standard data products can be calibrated;
b) Study the cross-calibration between three independent multi-polarization systems: SIR-C, the NASA/JPL DC-8 SAR, and the University of Michigan ground-based polarimetric scatterometer;
c) Evaluate the calibration "stability" of the SIR-C/X-SAR;
d) Develop a cost-effective calibration plan which includes the development of inexpensive polarimetric active calibrators.
Field Measurements:
I. a) A series of five different experiments covering internal and external procedures are planned. Oberpfaffenhofen and its surrounding area will serve as a master test site. The five experiments are: 1) Internal calibration; 2) Measurement of operational SAR antenna pattern; 3) Absolute calibration of SAR image data; 4) Mutual radiative coupling of clutter surrounded calibration targets; and 5) Attenuation of microwaves caused by woodlands.
II. a) Classification results will be based mainly on SAR information, however, non-satellite data (air photos, soil maps, forest maps, and ground truth) will be used as reference data and to verify the results.
III. a) Calibrate all the calibrators at standard ranges prior to deployment.
b) Use polarimetric active radar calibrators to estimate end-to-end polarization distortion of the SIR-C system. Use the estimated distortion parameters to extract a "best estimate" of the polarization scattering matrix of other targets on the ground.
c) Deploy inexpensive trihedral corner reflectors to characterize co-polarized channel imbalance in magnitude and phase over an area wider than that covered by the active calibrators in the primary calibration area.
d) Use multi-polarization ground receivers to record the system transmit azimuth pattern at several elevation cuts and to estimate the transmit polarization distortion.
e) Use calibrated multi-polarization ground scatterometers to provide in situ data over extended targets and compare them with SIR-C/X-SAR data of the same targets.
f) Evolve a cost-effective calibration strategy by comparing the "calibrated'' results obtained utilizing different calibration philosophies.
Crew Observations:
1) Crew Journal: Document weather conditions, forest and agricultural areas, and any burning activities at the site.
2) Cameras: Hasselblad and Linhoff cameras will be used to obtain stereo color photos of the site.
Coverage Requirements:
The minimum coverage requirements for the Oberpfaffenhofen, Germany test site are four (4) south-looking passes, preferably <=48deg..
Anticipated Results:
I. a) Quantitative analysis of SAR image data.
II. a) Differentiation of forested and non-forested areas with an assessment of the accuracy of separation.
b) Information on the tree stand geometry, age classes of trees, and seasonal changes.
III. a) Full polarimetric end-to-end characterization of the SIR-C/X-SAR system in the primary calibration target area within the limitations of instrument accuracy;
b) A better understanding of polarimetric calibration of space-borne microwave synthetic aperture radar.
References:
Freeman, A., J. C. Curlander, P. Dubois, and J. D. Klein, 1988. Shuttle-imaging Radar C Calibration Workshop Report, JPL Technical Report 88-003, Pasadena, CA, Nov. 1988.
Hartl, P., F. Heel, W. Keydel, and H. Kietzmann, 1987. Radar Calibration Techniques including Propagation Effects, Adv. Space Res., 7, 11, 259-268, 1987, 16. COSPAR Conference, Toulouse, France, July, 1986.
Seifert, P., H. Lentz, M. Zink, and F. Heel, 1992. Ground-based Measurements of Inflight Antenna Patterns for Imaging Radar Systems, IEEE Trans. Geosci. and Rem. Sensing, 30, 6.
Zink, M., F. Heel, and H. Kietzmann, 1991. The Oberpfaffenhofen SAR Calbration Experiment of 1989, J. of Electromag. Waves and Applications, 5, 9, 935-951.
Zink, M., 1993. X-SAR Calibration Plan, Part 1: System Analysis and Test Results, Oberpfaffenhofen, DLR, February.
Titles of Investigations:
I. High Alpine SAR Experiment
II. SIR-C Investigations of Snow Properties in Alpine Terrain
Principal Investigators:
I. Dr. Helmut Rott
University of Innsbruck
II. Dr. Jeff Dozier
University of California - Santa Barbara
Site Description:
The Ítztal test site is located in the Central Alps of Tyrol, Austria, north of the main east-west ridge of the divide between the rivers Inn and Danube, which drain to the Black Sea, and the river Etsch, which drains to the Mediterranean Sea. The mountains of upper Ítztal are composed of paragneisses with subordinate amphibolites and orthogneiss. The summits of the main peaks reach elevations of 3500 to 3768 meters above sea level. About 25% of the test site is covered by glaciers; the largest glacier is Gepatschferner which covers 17 km2. The firn areas of the large glaciers are located on plateaus above 2900 meters. These relatively level areas are considered to be relic landforms from the Miocene Epoch. The tongues of the large glaciers descend from the firn fields down into narrow valleys, which formed during the last ice age. Cirques below mountains ridges are frequently occupied by small cirque glaciers.
The treeline is at about 2100 meters above sea level. The highest perenially occupied farm house of the Austrian Alps, "Rofenhof", is at 2010 meters above the village of Vent. During the summer season, the Alpine grassland, up to the highest altitudes, is used as a grazing ground as it has been since pre-historic times. This is also known from the discovery of the 5000 year old man in the ice in this area. The ice-free areas above treeline are partly covered by alpine grasses and dwarf shrubs, and partly by bare rocks and glacial moraines. Due to terrain steepness and geomorphological conditions, many slopes are subject to erosion during the snowmelt season and during periods of intense summer rainfall, as evidenced by severe flashfloods in recent years. Whether ski resorts enhance flashfloods is a matter of controversy.
The test site's core area is the glacier region of the Venter Tal, which is one of the most intensively studied areas for glacier research in the world. Research in the Venter Tal include studies of glacier dynamics, glacier-climate relations, and snow and glacier hydrology. After dangerous outbreaks of glacier-dammed lakes, the first scientific glacier observations were reported in 1772 (Hoinkes, 1969). Continuous glacier surveys were initiated in the Vent valley in the 1890s, resulting in a valuable record of glacier-climate interactions (Kuhn, 1980). In addition to scientific research on glaciers and snow cover, these phenomena are also important to water management, water power production, and flood and avalanche protection. Permanent equipment for snow and glacier research includes two reseach stations at high altitudes, runoff gauges, and meteorological stations. The Institute of High Alpine Research of the University of Innsbruck is in Obergurgl, a ski resort at 1900 meters, is in the outer part of the test site. For several decades, this institute has been the base for extensive studies of high alpine ecology, including research on alpine plant physiology, environmental impacts of tourism, recultivation of erosion areas, properties of alpine and sub-alpine ecosystems, and post-glacial climate history (Moser and Peterson, 1981; Patzelt, 1988).
The fragile ecosystems of high alpine areas call for detailed studies of the environmental processes to assess the potential impact of climate change and of direct effects of human activities, as well as to establish the basis for better management of renewble and non-renewable resources. Earth observation from space is able to fulfill the need for improved information on ecology and hydrology of high alpine areas all over the world (Rott, 1990). For adequate use of remote sensing data, we believe it is crucially important to understand the relations between satellite measurements and physical targets properties and to develop standard algorithms for satellite data analysis. These goals are best achieved in test areas where extensive field measurements are carried out and proper validation of data analysis methods is possible.
For this reason, Ítztal has been chosen as a model site for applications of multiple parameter SAR in high alpine areas, with emphasis on hydrology and glacier applications. Previous campaigns in the test site with airborne SAR include the Canadian SAR-580, the AIRSAR of NASA/JPL, and the E-SAR of the German Aerospace Research Establishment. These campaigns were accompanied by extensive field measurements and were able to demonstrate the usefulness of SAR for these applications (Rott, 1984; Rott and Mätzler, 1987; Rott and Davis, 1993; Shi et al., 1991). Drastic temporal changes in the backscattering properties of snow and glacier areas were observed in single channel C-band SAR data of the European ERS-1 satellite, acquired through 1992 in five-week intervals (Rott and Nagler, 1993). Significant advancements in the development of inversion procedures for deriving physical properties of snow and ice from spaceborne SAR observations and for deriving automated procedures for target classification in complex terrain are expected from the SIR-C/X-SAR experiment in Ítztal.
Objectives:
I. a) Using surveyed test sites in the Alps, monitor glacier properties, map the seasonal snow cover, map geological and erosional features, obtain topographic mapping from radar stereo imagery, map alpine vegetation and sub-alpine forests.
II. a) Estimate snow-covered area and distribution of snow water equivalence over alpine drainage basins.
b) Estimate spectral albedo of snow cover.
c) Model spatial distribution of snow surface energy exchange, melt rate and snow metamorphism.
Field Measurements:
I. a) The physical properties and the back scattering signatures of the main targets will be measured on the ground and compared with the multi-parameter SAR signatures.
b) Digital elevation data, detailed thematic maps, and field measurements will be used for data analysis and validation.
c) Airborne imagery and optical satellite imagery will be obtained for comparison and will be used for generating multi-sensor data sets.
II. a) Validate remotely sensed measurements with intensive snow surveys coincident with SIR-C flights, and with scatterometer measurements at one site. To insure that results are not site-specific, field and satellite investigations will be carried out at other test sites in different climates including at sites in the Sierra Nevada (California) and Tien Shan (Xinjiang, northwest China).
b) Use optical sensor data to estimate grain size of surface snow layer and its contamination by absorbing impurities such as dust or soot. Use these parameters to extend albedo throughout the solar spectrum. AVIRIS data will be requested for US. sites and Landsat Thematic Mapper data will be used for foreign sites.
c) Use parameters measured from satellite or aircraft, local micrometeorological data, and digital elevation grids to drive basin-wide energy balance model of snowpack.
Crew Observations:
1) Crew Journal: Describe the snow, vegetation extent, and cloud cover at the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph the snow extent and to obtain stereo images of the site.
Coverage Requirements:
The minimum coverage requirements for the Ötztal, Austria test site are two (2) stereoscopic angles.
Anticipated Results:
I. a) Improve the understanding of the capabilities of spaceborne SAR for detection of physical properties of the seasonal snow cover and glaciers, and for deriving geological and erosional features;
b) Assess the feasibility of extracting information on alpine vegetation and sub-alpine forests from multiparameter SAR data;
c) Improve digital methods for thematic mapping of glaciers, snow cover, geologic structures and erosional features;
d) Improve methods for high-precision contour and line mapping using radar stereo imagery and assess mapping accuracies;
e) Assess the possibility for external radar calibration through backscatter measurements on homogeneous glacial areas; and
f) Determine the optimum SAR parameters for future advanced earth observation systems regarding operational tasks in alpine terrain.
II. a) Evaluation of the capability to model processes in the Earth's alpine snow cover.
b) SIR-C measurements of the snow cover will be calibrated with physical measurements of snow characteristics, thus providing excellent data for evaluation of models of the electromagnetic properties of snow.
References:
Hoinkes, H. C., 1969. Surges of the Vernagtferner in the Ötztal Alps since 1599. Can. J. of Earth Sci., 6(4), 853-861.
Kuhn, M., 1980. Climate and Glaciers. Sea Level, Ice, and Climate Changes., IAHS Publ. No. 131, 3-20.
Moser, W. and J. P. Peterson, 1981. Limits to Obergurgl's Growth. Ambia, Vol. 10 (2-3), 68-72.
Patzelt, G., Ed., 1988. The Man and Biosphere Project Obergurgl. Veröffentl. des Österr. MaB Hochgebirgsprogramms, Bd. 10, Univ. Verlag Wagner, Innsbruck.
Rott, H., 1984a. The analysis of backscattering properties from SAR data of mountain regions, IEEE J. Oceanic Eng. OE-9, 5, 347-355.
Rott, H., 1984b. Synthetic aperture radar capabilities for snow and glacier monitoring. Adv. Space Res., Vol. 4, 11, 241-246.
Rott, H., 1990. Snow and land ice in the climate system: research problems and possibilities of remote sensing. Remote Sensing and the Earth's Environment, ESA SP-301, 61-75.
Rott, H. and R. E. Davis, 1993. Multifrequency and polarimetric SAR observations on alpine glaciers. Annals of Glac., Vol. 17, in press.
Rott, H. G., G. Domik, C. Mätzler, and H. Miller, 1985. Towards a SAR system for snow and land ice applications. Proc. of Workshop on Thematic Applic. of SAR Data, ESA SP 257, 29-39.
Rott, H. and C. Mätzler, 1987. Possibilities and limits of synthetic aperture radar for snow and glacier surveying. Proc. of the Symp. on Rem. Sensing in Glaciology, Cambridge, Annals of Glac., Vol. 9, 195-199.
Rott, H., and T. Nagler, 1993. Snow and glacier investigations by ERS-1 SAR - first results. Proc. First ERS-1 Symp. - Space at the Service of Our Environment. ESA SP-359, 577-582.
Shi, J. C., J. Dozier, H. Rott, and R. E. Davis, 1991. Snow and glacier mapping with polarimetric SAR. Proc. of Third AIRSAR Workshop, JPL Publ. 91-30, 78-87.
Titles of Investigations:
I. Polarimetric Radar Observations of Forest State for Determination of Ecosystem Process
II. Multifrequency Imaging Radar Polarimetry: Geophysical Factors from Penetration Phenomena
III. SIR-C Polarimetric Radar Image Simulation and Interpretation Based on Random Medium Model
Principal Investigators:
I. Dr. Fawwaz Ulaby/Craig Dobson
University of Michigan
II. Dr. Howard Zebker
Jet Propulsion Laboratory
III. Dr. Jin Kong
Massachusetts Institute of Technology
Site Description:
The Raco supersite is at the eastern end of Michigan's Upper Peninsula. It is contained within a box defined by 46deg.40'N to 45deg.50'N latitude by 83deg.50'W to 85deg.10'W longitude; center coordinates are 46deg.15'N latitude and 84deg.30'W longitude. The site is located at the ecotone between the boreal forests and northern temperate forests, a transitional zone that is expected to be ecologically sensitive to anticipated global changes resulting from climatic warming. Baseline studies of vegetation communities are essential in monitoring such changes.
The site contains most boreal forests species as well as many of the temperate species, thus studies here serve to link studies performed well to the north and south. The distribution of forest communities is largely determined by a soil-controlled resource gradient established by glacial deposits such as moraines and outwash. Landscape patch sizes are large; homogeneous forest stands typically exceed 4 ha in size. Represented communities include northern hardwoods (sugar maple, red maple, beech, eastern hemlock, balsam fir), pines (jack pine, red pine, white pine), conifer bogs (black spruce, white spruce, northern white cedar, tamarack), hardwood swamps (red maple, white birch, aspen), and extensive areas of disturbance-induced pioneer species (trembling and bigtooth aspens). Importantly for development of robust radar scattering models for forests, these species represent two major branching architectures (excurrent and decurrent tree forms) and leaf types (broadleaf and needle-leaf).
The site is not totally forested. Numerous large areas of prairie and hayfields provide areas of relatively low biomass for biomass and soil moisture studies. These areas are scattered across the expected SIR-C/X-SAR image swath, and also provide sites for the deployment of point calibration targets. Arrays of trihedral reflectors and active transponders are deployed for this purpose over a 70 km x 100 km region and use both grass-covered surfaces and several large airfields. The target arrays are being used by US and Canadian teams for cross-calibration of the JPL AIRSAR, CCRS airborne SAR, ERS-1, and SIR-C/X-SAR.
The site has been imaged by the JPL AIRSAR (April and July 1990, June 1991), the CCRS airborne SAR (June 1989, October 1991), Seasat, JERS-1, and ERS-1. Located at the intersection of the ERS-1 ascending and descending nodes, the site was often imaged twice per day (at 12:30 and eleven hours later at 23:30). This multitemporal coverage provided by ERS-1 during its commissioning and multidisciplinary phases (with 3-day and 35-day repeat intervals, respectively) will complement the shorter, more intensive observation periods provided by SIR-C/X-SAR; and thus provides an excellent basis for examination of seasonal change over time scales which the shuttle-based SAR cannot match.
Over the last three years, a major investment has been made to develop the site for SIR-C/X-SAR and ERS-1 forest studies. The University of Michigan, in cooperation with Michigan Technological University, the United States Forest Service, and the Michigan Department of Natural Resources has established a series of well characterized forest "training" stands as a stratified sample of the various forest communities. At present, 30 stands (each 4 ha) have been inventoried using a 10% sample population for characterizing relatively static properties such as tree height, diameter, and stem count (by specie). By launch date, it is anticipated that approximately 100 forest stands will be inventoried. Allometric equations, based upon destructive sampling of the various species, are used to estimate aboveground biomass on a per tree basis and then summed within a stand to yield measures of dry biomass contained within tree trunks, branches, and foliage. Additional measurements include: tree architecture, leaf size and total leaf area, soil properties, and organic litter. Global Position System (GPS) coordinates have been obtained for the corners and sampling grid within each forest stand. These coordinates define one overlay in a Geographic Information System (GIS) for a 60-km x 60-km area which also contains overlays of digital elevation, surface geology, soils, land-use, land-cover, transportation networks, surface hydrology, and forest inventories. This GIS is linked to a relational data base containing time varying quantities for each stand such a leaf area, snow cover, soil and vegetation water status and microwave dielectric properties, etc.
Objectives:
I. a) Validate a vector, radiative transfer model (MIMICS) for estimating radar backscatter from forested terrain. Use this model to simulate expected SIR-C/X-SAR sensitivity to forest biophysical properties such as aboveground standing biomass and canopy water status and to surface hydrologic properties.
b) Develop inversion techniques for estimation of forest biophysical and hydrologic properties from SIR-C/X-SAR data using MIMICS simulations and airborne SAR data.
c) Test and evaluate the inversion techniques using SIR-C/X-SAR data.
II. a) Model, experimentally characterize, and verify penetration phenomena in hyperarid and vegetated regions using the SIR-C multiparameter radar system and ground-based receivers.
b) Invert measured radar backscatter as a function of frequency and polarization in terms of geophysical parameters of the surface, subsurface and vegetation canopy such as surface roughness, subsurface geomorphology, or tree height and density.
c) Display subsurface and within-canopy features in an image format, thus easing the interpretability of the results.
III. a) Demonstrate the applicability of the random medium model in simulating SIR-C Supersite imagery.
b) Analyze and interpret SIR-C imagery for remote sensing applications.
c) Investigate seasonal variations and atmospheric effects.
Field Measurements:
I. a) For the thirty forest stands, the following properties are measured:
* stocking density, height and diameter by specie;
* leaf area index;
* soil type;
* litter depth and
* surface roughness
Where appropriate, these measurements are updated to reflect changes resulting from interannual growth, phenologic development or disturbances. Meterologic conditions are monitored at Sault Ste. Marie and Strongs, MI. Additional moisture-related quantities are measured in conjunction with SAR operations and include: (1) snow extent, depth, density, temperature, and liquid water content; (2) soil moisture, density, and dielectric properties; (3) moisture content and density of the litter layer and; (4) moisture and dielectric properties of vegetation components (bark, sapwood, branches and foliage).
II. a) Deploy ground receivers during the experiment to measure field strengths at both vertical and horizontal polarizations. These in situ measurements will constrain and confirm our theoretical models.
Crew Observations:
1) Crew Journal: Document cloud types, presence of rain clouds, and extent of cloud cover, clearcutting activities, presence of fires and/or smoke, and snow extent.
2) Cameras: Linhoff and Hasselblad will be used to photograph the cloud cover, forests, and vegetation at the site.
Coverage Requirements:
Minimum coverage requirements for the Raco, Michigan site are three (3) ascending and three (3) descending at a range of incidence angles. Both day and night observations are highly desirable in order to evaluate effects of daily max./min. moisture and temperature conditions on SAR data. A launch window of 0600 to 0900 hours is ideal.
Anticipated Results:
I. a) Improve understanding of radar scattering by forests as demonstrated by modifications to and validation of a vector, radiative transfer model (MIMICS) as a robust approach for prediction of radar backscatter from a variety of forest and tree architectures.
b) Ascertain the dynamic range of radar backscatter from northern deciduous and coniferous forests in response to diurnal, daily, and seasonal dynamics of the canopy layer and the surface.
c) Define and evaluate techniques using SAR data to retrieve estimates of cover type, canopy structure, aboveground biomass, soil moisture, and plant water status for forested conditions.
II. a) An increased understanding of penetration phenomena in scattering.
b) Identification of sources for backscatter in hyperarid subsurface imaging, and quantitative assessment of the relative contribution of canopy top, volume, and ground surface scattering components to the return signal from vegetation canopies.
c) Solutions for descriptive geophysical parameters in the supersites studied. These results would be of great use to any investigators interpreting images acquired over similar targets by SIR-C/X-SAR or any other radar system.
III. a) Predicted multi-frequency, multi-incident angle, fully polarimetric supersite imagery prior to the actual SIR-C/X-SAR mission.
b) Interpreted SIR-C/X-SAR imagery with applications to vegetation classification, crop type, snow depth, seasonal and diurnal change studies.
c) Radar image simulation algorithm based on the random medium model for future radar sensor development.
d) Improved radar image processing algorithms for terrain classification.
e) Multi-layer random medium model for general earth terrain scattering.
References:
Dobson, M.C., L. Pierce, K. Sarabandi, and F.T. Ulaby, 1992. Preliminary analysis of ERS-1 SAR for forest ecosystem studies. IEEE Trans. Geosci. and Rem. Sens., Vol. 30, No. 2, 203-211.
Dobson, M.C., F.T. Ulaby, T. LeToan, A. Beaudoin, and E.S. Kasischke, 1992. Dependence of radar backscatter on conifer forest biomass. IEEE Trans. Geosci. and Rem. Sens., Vol. 30, No. 2, 412-415.
Dobson, M.C., R. DeLaSierra, and N. Christensen, 1991. Spatial and temporal variation of the microwave dielectric properties of loblolly pine trunks. Int. Geosci. and Remote Sensing Symp., IGARSS '91. IGARSS Digest, Vol. 3, 1107-1110.
Dobson, M.C., K. McDonald, F.T. Ulaby, and T. Sharik, 1991. Relating the temporal change observed by AIRSAR to surface and canopy properties of northern, mixed conifer and hardwood forests of Northern Michigan. Proc. of the Third Airborne Synthetic Aperture Radar (AIRSAR) Workshop, JPL, Pasadena, CA; JPL Publication 91-30, 34-43.
Dobson, M.C., T. Sharik, L. Pierce, and N. Christensen, 1991. Seasonal changes in radar from mixed conifer and hardwood forests in Northern Michigan. 1991 International Geosci. and Remote Sensing Symp., IGARSS '91. IGARSS Digest, Vol. 3, 1121-1124.
Ulaby, F.T., K. Sarabandi, K. McDonald, M. Whitt, and M.C. Dobson, 1990. Michigan Microwave Canopy Scattering Model (MIMICS). Intl. J. of Rem. Sens., Vol. 11, No. 7, 1223-1253.
Titles of Investigations:
I. SIR-C Surface and Subsurface Responses from Documented Test Site Localities in the Sahara, Namib, and Kalahari Deserts, Africa and the Jornada del Muerto, New Mexico
II. Multifrequency Imaging Radar Polarimetry: Geophysical Factors from Penetration Phenomena
Principal Investigators:
I. Dr. Gerald Schaber
U. S. Geological Survey
II. Dr. Howard Zebker
Jet Propulsion Laboratory
Site Description:
The Safsaf area is part of a flat plain, mostly mantled by sand sheet, that extends from south-central Egypt into northwest Sudan. This plain is also known as the Selima Sand Sheet or the Misaha surface. The bounding coordinates of the coverage required for this experiment are (approximately):
N 21deg., E 27deg. N 25deg.15', E 32deg.15'
N 26deg., E 30deg.40' N 24deg.30', E 33deg.25'
N 25deg.30', E 30deg.30' N 15deg., E 26deg.30'
N 27deg.45', E 33deg.15' N 15deg.40', E 25deg.15'
N 27deg.30', E 33deg.45' N 20deg., E 28deg.30'
This rectangular area has one "leg" (part of one pass) extending across the Nile and the Red Sea Hills to the coast; this extra leg covers localities for contingency deployment of the radar reflectors.
The Safsaf area lies along the SIR-A swath on which the penetration of dry surficial sands by the L-band signal, and our consequent delineation of subjacent materials and paleodrainage patterns, were first demonstrated. More than 100 pits were dug in the Safsaf area by hand and by backhoe in 1982, 1983, and 1984. This field work confirmed the shallow subsurface geologic units defined on the SIR-A images and provided data for models to explain the radar response of the calcareous duricrust (calcrete or caliche) in which paleodrainage patterns were preserved. Other sand-buried, subjacent materials whose radar responses can be studied are several types of bedrock, including a metamorphic core complex, limestone, sandstone, and a wide range of sediments. In terms of its radar characteristics, Safsaf is the best-known area in the hyperarid core of the Sahara. It is the classic locality in which to test the radar responses to be recorded by the SIR-C/X-SAR sensors.
Additional science in the Safsaf area include penetration studies to quantify the depth to which radar sensors can image subsurface features. Since SIR-A images have already illustrated sand-buried targets in the region, Safsaf is a good candidate for additional investigations by SIR-C/X-SAR. During SIR-C/X-SAR, ground field equipment will be deployed as part of a quantitative experiment to characterize the penetration depth.
Objectives:
I. a) Determine the optimum SAR sensor configuration for detection of desert duricrust and to use this understanding to reconstruct the paleoclimatic history of two large desert regions in Africa.
II. a) Model, characterize, and verify penetration phenomena in hyperarid and vegetated regions using the SIR-C multiparameter radar system and ground based receivers.
b) Invert measured radar backscatter as a function of frequency and polarization in terms of geophysical parameters of the surface, subsurface, and vegetation canopy such as surface roughness, subsurface geomorphology, tree height and density.
c) Display subsurface and within-canopy features in an image format facilitating result interpretability.
Field Measurements:
I and II. a) Deploy ground receivers during the experiment to measure field strengths at both vertical and horizontal polarizations. These in situ measurements will constrain and confirm our theoretical models.
Crew Observations:
1) Crew Journal: Document dust storms and weather conditions at the site. Note and sketch presence of subtle relict drainage patterns and aeolian sand transport pathways.
2) Cameras: Linhoff and Hasselblad will be used to obtain low sun angle stereo photographs of the desert.
Coverage Requirements:
The minimum coverage requirements for the Safsaf site are three (3) passes, preferably <=48deg..
Anticipated Results:
I. a) An improved understanding of radar backscatter and penetration in hyperarid-to-semiarid terrains that was initiated during our SIR-A/B investigations (Elachi, Roth and Schaber, 1984; Schaber et al., 1986);
b) Refinement of synergistic remote methods to identify various types and stages of datable, authigenic CaCO3 deposits related to successive changes in climate and surface geologic processes during the Quaternary;
c) Improved models of geometric scattering effects on SIR signal penetration; and
d) Significant new data on the spatial and chronological distribution of semiarid paleoclimatic zones in Africa.
II. a) An increased understanding of penetration phenomena in scattering;
b) Identification of sources for backscatter in hyperarid subsurface imaging, and quantitative assessment of the relative contribution of canopy top, volume, and ground surface scattering components to the return signal from vegetation canopies; and
c) Solutions for descriptive geophysical parameters in the supersites studied. These results would be of great use to any investigators interpreting images acquired over similar targets by SIR-C/X-SAR or any other radar system.
References:
Elachi, C. L.E. Roth, and G.G. Schaber, 1984. Spaceborne radarsubsurface imaging in hyperarid regions. IEEE Trans. Geosci. and Rem. Sens., GE-22, No. 4, 383-388.
Schaber, G.G., J.F. McCauley, C.S. Breed, and G.R. Olhoeft, 1986. Shuttle Imaging Radar: physical controls on signal penetration and subsurface scattering in the Eastern Sahara. IEEE Trans. Geosci. and Rem. Sens., GE-22, No. 4, 603-623.
Titles of Investigations:
I. Geologic and Hydrologic Studies of Saudi Arabia Under the Shuttle Imaging Radar (SIR-C) Science Plan
II. SIR-C Polarimetric Radar Image Simulation and Interpretation Based on Random Medium Model
III. The Exploration and Reconstruction of the Middle to Late Cenozoic Drainages of the Sahara by Means of the SIR-C Mapping
IV. SIR-C Surface and Subsurface Responses from Documented Test Site Localities in the Sahara, Namib, and Kalahari Deserts, Africa and the Jornada del Muerto, New Mexico
V. Multifrequency Imaging Radar Polarimetry: Geophysical Factors from Penetration Phenomena
Principal Investigators
I. Dr. Abdallah Dabbagh
King Fahd University
II. Dr. John McCauley
Northern Arizona University
III. Dr. Gerald Schaber
U. S. Geological Survey
IV. Dr. Howard Zebker
Jet Propulsion Laboratory
V. Dr. Jin Kong
Massachusetts Institute of Technology
Site Description:
The Sahara, an area the size of the USA, became desert about 2 Ma, but prior to that was apparently well-laced with major drainage networks. With increasing dominance of the wind, the sands in the channels and floodplains of the rivers were reworked into thin sheets and scattered dunefields. These widespread aeolian deposits masked the Tertiary continental history of the region and hid many of the relict river systems from view until the advent of SIR-A.
Several targets in the Sahara have been selected as sites for the SIR-C/X-SAR mission.
Eastern Sahara: Wadi Howar to Nile Valley and Gilf Kebir
Location: This area is adjacent to the Safsaf Calibration Supersite. It covers areas crucial for mapping paleodrainages between the Nile and Chad Basins. It is an irregularly shaped area whose corner coordinates are:
N 19deg.30', E 21deg. N 20deg., E 28deg.30'
N 25deg., E 25deg.20' N 22deg., E 30'
N 21deg., E 27deg. N 14deg.30', E 24deg.30'
N 15deg.15', E 23deg.10' N 17deg.15', E 24deg.40'
Science: The radar rivers discovered on the SIR-A image swath across Egypt and Sudan are thought to extend into the Chad Basin and then into the Atlantic Ocean (McCauley et al., 1986 a, b). This Trans-African Drainage hypothesis will be tested by examination of SIR-C/X-SAR imagery for evidence of continuation of the radar rivers' distinctive patterns in the shallow subsurface of Libya, Chad, and Sudan. This application of SIR-C/X-SAR for geological exploration is extremely important because of its potential for locating shallow groundwater in the sand-buried alluvial valleys of this impoverished region. Such previously unknown water resources (and other mineral resources) have been found in the radar river valleys of southern Egypt and also in buried river valleys discovered by random and (and expensive) wildcat drilling efforts in Libya (McCauley et al., 1986 a).
This area covers part of the probable course, now mostly obscured by windblown sand, of Wadi Howar, a relict river that in wetter times flowed across northern Sudan and is thought by some to be a tributary to the Nile. The paleo-flow direction is uncertain and controversial; Wadi Howar may be an independent, pre-Nile, consequent stream. SIR-C/X-SAR coverage may provide a means to discriminate among sizes of river gravels in buried fluvial deposits, and thus determine the "run" and the relation of Wadi Howar to the Nile River, if any. This region is of critical interest to all Paleodrainage Project members; areas around the Gilf Kebir Plateau and in the Nile Valley southwest of Aswan are well known to McCauley, Breed, and Issawi and the Wadi Howar area is a specialty of Prof. Pachur and his group in Berlin, and Maxwell.
Central Sahara: Wadi Tafassasset
Location: This area along the border of northern Niger with southeastern Algeria includes the course of Wadi Tafassasset, one of several relict tributary drainages that formerly flowed to the Niger River, but are now mostly defunct and obscured by sand sheets and dunes.
Science: The Tafassasset area is bounded (approximately) by latitudes 20deg. and 24deg.30'N, and by longitudes 7deg.30' and 11deg.30'E (see map). This area has been studied by French geologists, including H. Faure, using conventional geologic field methods. Faure's group is presently using SPOT imagery to map the drainage patterns that are visible in certain places; other, key areas are obscured by sand and will only be mappable from the SIR-C/X-SAR coverage. SIR-C/X-SAR has the potential to greatly increase our knowledge of the evolutionary history of this part of the Central Sahara in relation to paleoclimatic conditions, regional tectonics, and the capture and reversal of the Niger River system.
Objectives:
I. a) Major objectives are the utilization of multiple-polarization, dual frequency, radar remote sensing imagery, and synthetic aperture radar to detect lithological boundaries, distinguish tectonic features, detail fluvial geomorphology, and elucidate hydrologic systems in large areas having a thin sand cover.
II. a) Integrate and map relic Cenozoic drainage systems across the Sahara using SIR-C data in a synoptic mode with other remotely sensed data, field, and cartographic data.
b) Demonstrate applicability of SIR data, used synergistically with Landsat, SPOT and high-altitude photographic data, for exploration geology.
c) Produce a major report on the distribution of paleodrainages in the Sahara, their relations to the basic tectonic elements of North Africa (basins and swells), and their economic potential.
III. a) Determine the optimum SIR sensor configuration for detection of desert duricrust and to use this understanding to reconstruct the paleoclimatic history of two large desert regions in Africa.
IV. a) Model, experimentally characterize, and verify penetration phenomena in hyperarid and vegetated regions using the SIR-C multiparameter radar system and ground-based receivers.
b) Invert measured radar backscatter as a function of frequency and polarization in terms of geophysical parameters of the surface and subsurface such as surface roughness and subsurface geomorphology.
c) Display subsurface features in an image format, thus easing the interpretability of the results.
V. a) Demonstrate the applicability of the random medium model in simulating SIR-C Supersite imagery.
b) Analyze and interpret SIR-C imagery for remote sensing applications.
c) Investigate seasonal variations and atmospheric effects.
Field Measurements:
I. a) Field observations will be carried out to collect ground truth data on joint systems, fold structures, fault systems, rock types, thickness of sand layer over paleodrainages, dune dimensions and orientation, and vegetation density.
II. a) Testpits will be excavated and documented to determine the distribution and composition of buried fluvial deposits located by their radar signatures on SIR-C/X-SAR images, for reconstruction of paleodrainage systems and potential aquifers.
b) Samples will be collected in testpits to record the stratigraphic sequences of buried fluvial deposits for radiometric dating and interpretation of regional geologic and paleoclimatic history.
c) Field measurements by Schaber will be used to support this research effort.
III. a) Deploy series of six to eight JPL-provided corner reflectors (8-foot diameter) required for minimum calibration in support of the Sahara EM-Theory supersite investigation during SIR-C/X-SAR.
b) Excavate a series of backhoe trenches in order to document the physical and geologic (stratigraphic) controls on signal penetration and backscatter down several meters. Full photo-documentation and sketching of surface and trench walls.
c) Collect soil, sand, and duricrust samples for determination of petrology, moisture content, and electrical properties measurements.
d) If feasible, in situ electrical properties measurements.
e) Location of trenches and corner reflectors using Magellan NAV-5000 GPS Navigator.
IV. a) Deploy ground receivers during the experiment to measure field strengths at both vertical and horizontal polarizations. These in situ measurements will constrain and confirm our theoretical models.
Crew Observations:
1) Crew Journal: Document dust storms and vegetation extent. Sketch any drainage patterns at the site.
2) Cameras: Linhoff and Hasselblad will obtain low sun angle photographs of the desert.
Coverage Requirements:
1) Coverage of the Eastern Sahara area requires eight short swaths, with 10% side overlaps (total length approximately 5,000 km). All coverage for the Paleodrainage Experiment should be in Mode 11, with the widest possible swath.
2) Two "boxes" are shown on the map, representing both orientations of the potential SIR-C/X-SAR coverage. The NW-SE, narrower but longer rectangle would be best for tracking the course of the Tafassasset paleodrainage system from the Djanet (Ft. Charlet) area into the sand-covered desert (Tenere du Tafassasset and Erg of Bilma). The corner coordinates of that box are:
N 21deg.45', E 7deg.50' N 20deg., E 12deg.
N 22deg.45', E 9deg.20' N 19deg., E 10deg.40'
Coverage of that box would require two short swaths, each 500 km long, with 10% overlap (again in Mode 11).
Anticipated Results:
I. a) Significant new data on joint systems and fold structures, as well as some of the major fault systems.
b) Exploration of Pleistocene paleodrainage system with major implications for regional hydrology.
c) Contributions to the archaeological geology by way of ancient irrigation channels and now buried settlements.
II. a) Major contribution to the knowledge of the nature and scope of the erosional events from middle to later Tertiary time, which gave rise to the present (Quaternary) geomorphology of North Africa.
b) A major report will be prepared with accompanying maps that we hope will have broad scientific and economic applications (for both the public and private sectors).
III. a) An improved understanding of radar backscatter and penetration in hyperarid-to-semiarid terrains that was initiated during our SIR-A/B investigations (Elachi, Roth, and Schaber, 1984; Schaber et al., 1986).
b) Refinement of synergistic remote methods to identify various types and stages of datable, authigenic CaCO3 deposits related to successive changes in climate and surface geologic processes during the Quaternary.
c) Improved models of geometric scattering effects on SIR signal penetration.
d) Significant new data on the spatial and chronological distribution of semiarid paleoclimatic zones in Africa.
IV. a) An increased understanding of penetration phenomena in scattering;
b) Identification of sources for backscatter in hyperarid subsurface imaging.
c) Solutions for descriptive geophysical parameters in the supersites studied. These results would be of great use to any investigators interpreting images acquired over similar targets by SIR-C/X-SAR or any other radar system.
V. a) Predicted multi-frequency, multi-incidence angle, fully polarimetric supersite imagery prior to the actual SIR-C/X-SAR mission.
b) Interpreted SIR-C/X-SAR imagery with applications to seasonal and diurnal change studies.
c) Radar image simulation algorithm based on the random medium model for future radar sensor development.
d) Improved radar image processing algorithms for terrain classification.
e) Multi-layer random medium model for general earth terrain scattering.
References:
Breed, C. S., J. F. McCauley, and P. A. Davis, 1987. Sand sheets of the Eastern Sahara and ripple blankets on Mars. In Frostick, L., and Reid, I. (eds.), Desert Sediments: Ancient and Modern, London Geological Society Special Publ. No. 35, 337-359.
Elachi, C., L. E. and G. G. Schaber, 1984. Spaceborne radar subsurface imaging in hyperarid regions. IEEE Trans. Geosci. and Rem. Sens., GE-22, No. 4, 383-388.
Issawi, B., and J. F. McCauley, 1992, The Cenozoic Rivers of Egypt: The Nile problem. In Adams, B., and Friedman, R. (eds.), The Followers of Horus. Oxbow Press, Oxford, England.
Kogbe, C. A. (ed.), 1989. Geology of Nigeria. Rock View Ltd., Jos, Nigeria, 538 pp.
McCauley, J. C. S. Breed, and G. G. Schaber, 1986a. The megageomorphology of the radar rivers of the Eastern Sahara. Second Spaceborne Imaging Radar Symposium, Pasadena, CA. JPL Pub. 86-26, 25-35.
McCauley, J. F., Breed, C. S., Schaber, G. G., McHugh, W. P., Issawi, B., Haynes, C. V., Grolier, M. J., and El Kilani, A., 1986b. Paleodrainages of the Eastern Sahara --The Radar Rivers Revisited (SIR-A/SIR-B Implications for a mid-Tertiary trans-African Drainage System. IEEE Trans. Geosci. and Rem. Sensing, v. GE-24, No. 4, 624-648.
Maxwell, T. A., and V. H. Haynes, 1989, Large-scale, low-amplitude bedforms (chevrons) in the Selima Sand Sheet, Egypt, Science, 243, 1179-1182.
Pachur, H. J., and S. Kröpelin, S., 1987. Wadi Howar: Paleoclimatic evidence of an extinct river system in the Southeastern Sahara, Science, 237, 298-300.
Schaber, G. G., J. F. McCauley, C. S. Breed, and G. R. Olhoeft, 1986, Shuttle Imaging Radar: physical controls on signal penetration and subsurface scattering in the Eastern Sahara, IEEE Transactions on Geosci. and Remote Sensing, GE-24, no. 4, 603-623.
Williams, M. A. J., and H. Faure (eds.), 1980, The Sahara and the Nile. Balkema Publ. Co., Rotterdam, 607 pp.
Titles of Investigations:
I. Wave Dynamics in the Southern Ocean
II. Optimization of SAR Parameters for Ocean Wave Spectra
Principal Investigators
I. Mr. Robert Beal
Applied Physics Lab/Johns Hopkins University
II. Mr. Frank Monaldo
Applied Physics Lab/Johns Hopkins University
Site Description:
The supersite is located in the Southern Ocean between 30deg. South and 57deg. South, but especially the few most intense storms in that region.
Objectives:
I. a) Construct a spatially continuous daily estimate of the directional wave energy transport across the only pure-ocean circumpolar route on the planet, a route that is just to the south of the net source function (i.e., south of the maximum wind zone).
II. a) Determine the relative contributions from proposed mechanisms for the imaging of ocean surface waves by SARs.
b) Establish the dependence upon geometry, radar frequency, ocean wave height, and wind speed and direction of the loss of azimuth resolution associated with SAR wave imaging.
c) Select a set of SAR parameters (geometry, frequency, polarization) that maximizes the fidelity of SAR derived, two-dimensional ocean wave spectra in the context of azimuth resolution limits.
Field Measurements:
Sea-truth measurements are not planned during the mission. Highest priority site locations will be determined using real-time global wave model forecasts from either the Navy Fleet Numerical Oceanography Center or the European Center for Medium-range Weather Forecasts.
Crew Observations:
1) Crew Journal: Document weather and ocean conditions. Describe and sketch ocean surface and waves. Locate and describe any storm activity near the site.
2) Cameras: Linhoff and Hasselblad will be used to photograph any waves and storms; low angle sun glint photographs are requested.
Coverage Requirements:
The minimum coverage requirements for the Southern Ocean site are 14 passes (APL and taped).
Anticipated Results:
I. From this data set, and by extending our L-band algorithms developed and verified with SIR-B, we will:
a) Estimate the angular distribution of total wave energy flux through the 58deg.S latitude circle and partition the total energy into sixteen 22.5deg. longitude zones;
b) Determine the temporal and spatial variability of the directional wave energy transport in each of the 22.5deg. zones over the total mission duration; and
c) Calculate the angular distribution of total wave energy transport versus longitude by normalizing the (relative) spectra with the mean monthly wave height determined from Geosat altimeter averages, which are essentially invariant from year to year (based on 1985 to 1987 data).
II. a) New and/or improved models describing the mechanisms involved in SAR imaging of ocean features and improved definition of the limits of applicability of SAR in a maritime environment.
b) An improved understanding of how current boundaries are imaged with SAR and of the detectability criteria for current boundaries.
c) Advances in the understanding of major physical mechanisms driving the generation, propagation, and dissipation of ocean phenomena, such as swell, internal waves, and near surface fine-scale features.
d) Compilation of SAR images and ship wake characteristics correlated with radar, ship, and meteorological parameters.
e) Improved understanding of the mechanisms responsible for SAR imaging of wake characteristics at L, C, and X-band radar frequencies in different sea states.
f) Evaluation of SAR's potential use in synoptic detection/observation/monitoring.
References:
Beal, R. C., T. W. Gerling, D. E. Irvine, F. M. Monaldo, and D. G. Tilley, 1986. Spatial variations of ocean wave directional spectra from the Seasat Synthetic Aperture Radar, J. Geophys. Res. 81, 2433-2449.
Beal, R. C., 1987, A Hybrid ROWS/SAR approach to monitor ocean waves from space, Johns Hopkins APL Technical Digest, Vol. 8, Jan.-Mar.
Beal, R. C. (ed.), 1991. Directional Wave Spectra, The Johns Hopkins University Press.
Beal, R. C., T. W. Gerling, F. M. Monaldo, and D. G. Tilley, 1991. Measuring scean waves from space: 1978 to 1988, Int. J. of Remote Sensing 12, 1713-1722.
Beal, R. C. and D. G. Tilley, 1992, ERS-1 and Almaz ocean wave monitoring experiments. Proceedings of IGARSS "92, Houston, TX, May 26-29, 1992.
Bruning, C., W. Alpers, L. F. Zambresky, and D. G. Tilley, 1988, Validation of a synthetic aperture radar ocean wave imaging theory by the Shuttle Imaging Radar-B experiment over the North Sea, J. Geophys. Res. 93, 15403-15425.
Bruning, C., W. Alpers, and K. Hasselmann, 1990, Monte-Carlo simulation studies of the non-linear imaging of a two dimensional surface wave field by a synthetic aperture radar, Int. J. Remote Sensing, 11, 1695-1727.
Clancy, R. M., J. E. Kaitala, and L. F. Zambresky, 1986, The Fleet Numerical Oceanography Center Global Spectral Ocean Wave Model, Bull. Am. Meteorol. Soc., 67, 498-512.
Gerling, T. W., 19XX. Partitioning Sequences and Arrays of Directional Ocean Wave Spectra into Component Wave Systems, J. Atmospheric and Oceanic Tech., 9, 444-458.
Hasselmann, K. and S., C. Bruning, A. Speidel, 1991. Interpretation and application of SAR wave imaging spectra in wave models, in Directional Ocean Wave Spectra (ed. R. C. Beal), The Johns Hopkins University Press, 117-124.
Kjeldsen, S. P. 1991. The practical value of directional ocean wave spectra. In Directional Ocean Wave Spectra (ed. R. C. Beal), The Johns Hopkins University Press, 13-19.
MacArthur, J. L. and S. F. Oden, 1987. Real-Time Global Ocean Wave Spectra from SIR-C, IGARSS 1987, Ann Arbor, 1105-1108.
Monaldo, F. M., T. W. Gerling, and D. G. Tilley, 1991. The implication of spatial variations in the SIR-B SAR wave spectra in the vicinity of Hurricane Josephine on the nature of the SAR modulation transfer function, IGARSS 1991, Helsinki.
Monaldo, F. M. and D. R. Lyzenga, 1986. On the estimation of wave slope and height variance spectra from SAR imagery, IEEE Trans. Geosci. Rem. Sens. GE-24, 541-551.
Tilley, D. G., 1989. Estimating aircraft SAR response characteristics and ocean wave spectra in the Labrador Sea extreme waves experiment, IEEE Trans. Geosci. Rem. Sens., 27, 483-491.
Tilley, D. G., 1991. SAR scattering mechanisms as inferred from LEWEX spectral intercomparisons. In Directional Ocean Wave Spectra, (ed. R. C. Beal), The Johns Hopkins University Press, 110-116.
Vachon, P. W., F. W. Dobson, and M. Khandekar, 1992. High sea state validation of the ERS-1 SAR, IGARSS 1992, Houston, TX, May 26-29, 1992.
WAMDI Group, 19xx. The WAM Model: A Third Generation Ocean Wave Prediction Model, J. Phys. Oceanogr. 18, 1775-1810.
Titles of Investigations:
I. The Joint Analyses of Single- and Dual-Frequency/Experimental Dual-Polarization SIR-C and X-SAR Measurements in Precipitation
II. Remote Sensing of Precipitation by Spaceborne Synthetic Aperture Radar
III. Reconstruction of the Mesoscale Velocity Shear Seaward of Coastal Upwelling Regions from the Refraction of the Surface Wave Field
Principal Investigators:
I. Dr. Arthur Jameson
Applied Research Corp.
II. Dr. Fuk Li
Jet Propulsion Laboratory
III. Dr. Pierre Flament
University of Hawaii
Site Description:
SIR-C/X-SAR's two experiments involving rain offer a unique challenge to the operation of the radar during the flight. Whereas all other experiments can be reasonably tied to a specific area on the surface of the Earth, the rain experiments only require that a reasonably "deep" rainstorm be in progress. The requirement is a difficult one because weather targets are transitory in both space and time and cannot be scheduled. The probability of observing a good target depends on the correlation time of the weather event, the average frequency of events, and the number of independent looks at the target. Since the planning process for the Shuttle flight requires a fixed location, the rain experiments have been chosen to concentrate on an area where longer correlation times may exist. Such areas associated with monsoons and tropical convective systems near the Intertropical Convergence Zone and mid-latitude mesoscale convective complexes, which naturally leads one to either the western or eastern Pacific.
Given the additional necessity of being seasonally independent and other mission planning realities, a large area in the western Pacific was chosen for the "rain supersite". This area has the additional advantage of containing a weather monitoring station at Guam and of being relatively low in contention with other SIR-C/X-SAR sites.
Objectives:
I. a) Determine the vertical and horizontal spatial distribution of hydrometeors in precipitating clouds.
b) Measure the spatial distribution of liquid water and ice in the clouds.
c) Measure and determine the limits of measurement of the polarization characteristics related to the shapes and orientations of hydrometeors in precipitating clouds.
II. a) Demonstrate, as a proof-of-concept, quantitative measurements of rainfall intensity from space using SIR-C/X-SAR.
b) Demonstrate the use of the synthetic aperture technique to improve the along-track spatial resolution in the presence of rainfall velocity dispersion.
c) Determine the mean rainfall velocity by extracting the Doppler spectrum centroid relative to the surface returns.
d) Study the backscattering and polarization characteristics of the ocean surface echoes in the presence of rain.
III. a) Project geographically related to "Reconstruction of the Mesoscale Velocity Shear Seaward of Coastal Upwelling Regions from the Refraction of the Surface Wave Field."
Field Measurements:
Due to the transitory nature of the rain supersite, field measurements have not been scheduled.
Crew Observations:
1) Crew Journal: Document storm areas and locate areas of intensive storms within the storm region. Identify potential storm activity for future potential data takes.
2) Cameras: Linhoff and Hasselblad will be used to photograph the ocean surface and any storm activity near or at the site.
Coverage Requirements:
Approximately one datatake per day has been scheduled for the nine-day mission. This may change depending upon the weather conditions during the mission.
Anticipated Results:
I. a) The combination of precipitation on SIR-C surface measurements will be identifiable;
b) Analytical techniques, such as those that will be used for the retrieval of rainfall from data collected during the Tropical Rainfall Measuring Mission (TRMM) can be studied before the TRMM launch. Those results will have an ultimate impact on the Earth Observing System (EOS) initiative that NASA in pursuing;
c) These first precipitation polarization measurements from space will help determine their future potential application for global microphysical measurements from space for use in EOS; and
d) Unique radar studies of precipitation may be possible since data may be collected over intense convective systems over which aircraft bearing radars have not been able to fly.
II. a) Quantitative evaluation of the rainfall rate;
b) Quantitative measure of the average rainfall velocity;
c) Quantitative measure of the height of the rain cloud;
d) Achievable spatial resolution for rainfall measurement applications using synthetic aperture synthesis;
e) Quantitative measure of the modification in the ocean scattering mechanism as a result of the impinging raindrops, and comparison of such results with theory and previously obtained experimental data; and
f) Polarization signature of the ocean and signature's variation in the presence of precipitation.
III. a) Project geographically related to "Reconstruction of the Mesoscale Velocity Shear Seaward of Coastal Upwelling Regions from the Refraction of the Surface Wave Field."
References:
Atlas, D. and R. K. Moore, 1987. The measurement of precipitation with synthetic aperture radar. J. Atmos. Oceanic Tech., 4, 368-376.
Hall, M. P. M., S. M. Cherry, and J. W. F. Goddard, 1984. Identification of hydrometeors and other targets by dual-polarization radar. Radio Sci., 19, 132-140.
Jameson, A. R., 1983a. Microphysical interpretation of multi-parameter radar measurements in rain. Part I: Interpretation of polarization measurements and estimation of raindrop shapes. J. Atmos. Sci., 40, 1792-1802.
Jameson, A. R., 1983b. Microphysical interpretation of multi-parameter radar measurements in rain. Part II: Estimation of raindrop distribution parameters by combined dual-wavelength and polarization measurements. J. Atmos. Sci., 40, 1803-1813.
Jameson, A. R., 1985. On deducing the microphysical character of precipitation from multiple parameter radar polarization measurements. J. Cli mate Appl. Meteor., 24, 1037-1047.
Meneghini, R., J. Eckerman, and D. Atlas, 1983. Determination of rain rate from a spaceborne radar using measurements of total attenuation. IEEE Trans. Geo. Sci. Rem. Sens., GE-21, 34.
In addition to the main Supersites, Backup Supersites were also chosen. The Backup Supersites provide redundancy in terms of the major objectives of some of the supersites.
Ron Brown
Canada Center for Remote Sensing
The test site is located near the town of Altona, Manitoba which is about 80 kilometers south of Winnipeg in western Canada. This test site is about 4 x 20 miles in size with approximately 700-800 fields contained in the area. It is located in the Red River Basin and is characterized by rich farmland where a variety of crops are grown including wheat, barley, canola, corn, sunflower, and sugar beets. The soils were developed under tall-grass prairie and meadow-grass on sandy to silty lacustrine and deltaic sediments with smooth, very gently sloping topography. Recent clay overwash from shallow runways occurs as a surface mantle in a number of locations within the site. Due to soil fertility, the original vegetation has largely disappeared and has been replaced by arable agriculture and windbreaks. Native wooded areas occur adjacent to streams, shallow water runways, and homestead locations.
J. Melack
University of California, Santa Barbara
Richard Moore
University of Kansas
Jack Paris
California State University, Fresno
The Gran Pantanal is an extensive (ca 150,000 km2) floodplain on the upper Paraguay River, located mostly in Brazil (Mato Grosso do Sul state). The tropical climate, marked seasonality in rainfall, and generally flat relief create a mosaic of savanna interspersed with permanent water bodies and patches of semi-deciduous forest, much of which is subject to inundation during part of the year. The inundation cycle within this huge floodplain is very complex, since the rivers contributing to the flooding have varying seasonal flood peaks . A wide variety of vegetation types occur, including dense forest, woody savanna, bush savanna, and floating meadows.
The objectives of the SIR-C/X-SAR investigations at this site include:
Identification of the radar signatures of the major floodplain habitats: open water, floating grasses, mixed floating macrophytes, flooded dicot forests of varying stature and palm stands.
Assessment of the degree to which the presence or absence of standing water can be detected under flooding plain vegetation, and whether water-saturated and flooded grassland environments are distinguishable.
Estimate regional inundation as input to ongoing biogeochemical studies.
Apply models of radar backscatter to tropical floodplains.
Reference
Vila da Silva, J. D. S., and H. J. H. Kux, 1992. Thematic mapper and GIS data integration to evaluate the flooding dynamics within the Pantanal, Mato Grosso do Sul State, Brazil. Proceedings of the 1992 IEEE Geoscience and Remote Sensing Symposium (IEEE: Piscataway, New Jersey), pp. 1478-1480.
A. Jameson
Applied Research Corporation
F. Li
JPL
Two experiments will be conducted at the Eastern Pacific test site. The first will determine the effect of precipitation on SIR-C and X-SAR measurements. These radar data will be analyzed using radiative transfer models to provide profiles of the attenuation coefficient (a). The use of a-R relationships will then be used to derive the vertical profile of the rain rate (R). Dual-frequency radar data provided by SIR-C/X-SAR will overcome beam-filling problems and provide information on the spatial distribution of ice and liquid water in the clouds.
The second experiment involves several proof-of-concept experiments for remote sensing of precipitation by the SIR-C/X-SAR. These experiments will significantly increase the understanding of the ability of spaceborne synthetic aperture radar to conduct global measurement and monitor precipitation.
P. Flament
University of Hawaii
This study will examine the small-scale velocity structure of the front separating cold Pacific equatorial water from warmer tropical water to the north. This front develops as instability waves in the autumn during non-El Niño years when the North Equatorial Current is most intense. The waves have lengths of about 1200 km and propagate westward at about 0.5 m/s. As these waves are major contributors to heat and momentum fluxes in these regions, it is important to understand the mechanisms responsible for their growth and their effects on thermohaline structure on the equatorial current systems. In addition, it is important to study the processes that mix the narrow cold filaments with the surrounding warm tropical water; these are at present largely unknown.
SIR-C/X-SAR images will be used to map the interaction of swell and current shear, convergence zones, and small-scale variability in surface wind stress and to use AVHRR images of sea surface temperature to locate thermal boundaries. Real-time AVHRR images will be collected at the University of Hawaii receiving station.
SAR images using multiple frequencies are needed to locate and assess the wave structure at the current shear zones. Ocean-truth measurements will be attempted using ships of opportunity during the SIR-C/X-SAR flights and include temperature, salinity, density, and velocity. The latitudes of the fronts can vary between 1deg.N and 7deg.N within 130deg.W and 180deg.W longitude. Frequent SAR sampling, both spatially and temporally, is needed to determine front locations, frontal wavelengths, and wave propagation velocity, and to compensate for high and low wind periods which may preclude detection of the wave/current interaction.
P. Mouginis-Mark
University of Hawaii
The Hawaiian test site centers on the Ka'u Desert, which extends from the summit of Kilauea Volcano along the Southwest Rift Zone towards the ocean. Bordered by Mauna Loa Volcano to the Northwest and the Koae Fault system to the Southeast, the Ka'u desert contains many lava morphologies and ash deposits that are expected on other volcanoes (Gaddis and Mouginis-Mark, 1987).
Rift zone eruptions in Hawaii produce different lava flow morphologies and erupt at the surface at different rates compared to the summit activity (Wadge, 1981; Rowland, 1987; Rowland and Walker, 1987). Some structural features associated with the rift zones of Mauna Loa appear to reflect the interaction between magma injection into the upper parts of the volcano, gravitational slumping of the edifice, and the buttressing of the flanks by adjacent volcanoes (Lipman, 1980). By using SIR-C/X-SAR data to map the spatial distribution of fractures, and the variation in flow types and ash deposits produced along the rift zones of Mauna Loa and Kilauea volcanoes, changes in eruption style may be related to dike propagation and the internal structure of the volcanoes (Ryan et al., 1981; Head and Wilson, 1987).
References
Gaddis. L. R. and P. J. Mouginis-Mark, 1987. Identification of lava flow surface textures: SIR-B radar image texture, field observations and terrain measurements. Photogram. Eng. Rem. Sens.
Head, J. W. and L. Wilson, 1987. Lava fountain height at Pu'u O'o Kilauea, Hawaii: Indicators of amount and variations of exsolved magma volatiles. J. Geophys. Res.
Lipman, P. W., 1980. The Southwest Rift Zone of Mauna Loa: Implications for structural evolution of Hawaiian volcanoes. Amer. J. Sci., 280-A, p. 752-776.
Rowland, S. K., 1987. The Flow Character of Hawaiian Basalt Lavas. Unpublishd Ph.D. Thesis, Univ. of Hawaii, 118 pp.
Rowland, S. K. and G. P. L. Walker, 1987. Toothpaste lava: Characteristics and origin of a lava structural type transitional between pahoehoe and a'a. Bull. Volcanol., 49, p. 631-641.
Ryan, M. P., R. Y. Koyanagi and R. S. Fiske, 1981. Modelling the three-dimensional structure of macroscopic magma transport systems: Applications to Kilauea Volcano, Hawaii. J. Geophys. Res., 86, p. 7111-7129.
Wadge, G., 1981. The variation of magma discharge during basaltic eruptions. J. Volcanol. Geotherm. Res., 86, p. 2971-3001.
T. Farr
Jet Propulsion Laboratory
SIR-C/X-SAR data from the Hotien East, China test site will be used to determine the history of Quaternary climate change for a portion of northwestern China. This history will be included in global paleoclimate models and reconstructions of the tectonic history of the area. This work will test the hypotheses that: 1) Chronologies developed at a few widely separated sites in northwestern China may be used to correlate surfaces and make surface-age maps using remote sensing data; 2) These maps contain information about the temporal and spatial distribution of climate changes that can be related to other global climate records; and 3) The surface-age maps can be used to date fault movements over a large area of northwestern China.
The specific objectives are to: 1) Determine the extended spectral signatures of desert piedmont surfaces and landforms of different ages using laboratory, field, and remote sensing data in a few widely separated test sites in northwestern China where chronological control is available or can be developed; 2) Use the spectral signatures to map the distribution and correlate the ages of surfaces and landforms related to past climate changes; 3) Determine the history of Quaternary climate change for the region based on the maps and ages; 4) Determine the ages of Quaternary movements on some of the large, active faults in northwestern China; and 5) Compare the types, rates, and magnitudes of surficial modification processes that have operated in northwestern China to those in the southwest U.S. which are also being studied.
J. Ranson
Goddard Space Flight Center
K. Paw U
University of California, Davis
Jin A. Kong
Massachusetts Institute of Technology
The Howland Backup Supersite has been the focus of intensive ecosystem and remote sensing studies since 1989. In addition, over the past several years extensive atmospheric monitoring activities have been supported by the Spruce Fir Cooperative, National Acidic Deposition Project and the Mountain Cloud Chemistry program. NASA Headquarters-sponsored Forest Ecosystem Dynamics-Multisensor Aircraft Campaign (FED-MAC) experiments were conducted at the Howland site during August-September 1989, March, July, and September 1990 and June 1991. Airborne JPL AIRSAR (C-, L-, and P-band) were acquired during 1989, 1990, and 1991. Additional aircraft measurements, including ER-2 AVIRIS, C-130 ASAS, and NS001 and UH-1 helicopter optical radiometers have been acquired. Data from aircraft and field measurements have been cataloged in a computerized data base which is available through the Forest Ecosystem Dynamics Project at Goddard Space Flight Center Biospheric Sciences Branch.
On or near the Howland site, there are a variety of different aged clearing, small plantations, and larger expanses of natural forest cover. This natural forest is transitional boreal with major forest types of spruce-hemlock, hemlock-mixed hardwoods and mixed hardwood. Because of the glacial history of the area, soil drainage classes vary from well-drained to very poorly-drained over limited distances producing a complex mosaic of forest communities. In addition, significant areas of bogs and wetlands occur throughout the area. This variety of forest ecosystem types within a localized area was the primary factor for the selection of this site. Another important consideration was the excellent logistics in place to support field and aircraft activities.
Extensive forest canopy and soil characteristics for numerous forest stands have been acquired for the site. Sample plot measurements for 60 stands include DBH, height, height to live crown, angle of bole, leaf area index estimates and soil organic analysis. A stem map was created in 1989 for a 200 x 150 meter area of spruce-hemlock forest. Tree architecture measurements for spruce and hemlock, including bole, branch, and needle angle distributions were acquired. Additional forest stand measurements are being acquired as needed.
T. Engman and J. Wang
Goddard Space Flight Center (GSFC)
Mahantango will be one of several SIR-C/X-SAR hydrology test sites. The hydrology studies at Mahantango will be conducted in a 400 km2. A series of aircraft flights with a P-, L-, and C-band polarimeter (a synthetic aperture radar system with multiple polarizations), an L-band microwave radiometer, as well as visible and infrared sensors have been made over the test site during July 1990. Extensive ground truth measurements on soil moisture, vegetation cover, surface roughness, hydrological, and climatological information have been acquired to support the studies. Similar data will be collected during the SIR-C/X-SAR mission.
The objectives of the two studies being carried out at the Mahantango site are:
1) To determine and compare soil moisture patterns within one or more humid watersheds using SAR data, ground-based measurements, and hydrologic modeling;
2) To use radar-derived soil moisture patterns to characterize the hydrologic regime within a catchment;
3) To identify runoff-producing characteristics of humid zone watersheds by seasonal and daily differences in the distribution of soil moisture;
4) To establish the feasibility of using space radar data as the basis for scaling up from small-scale, process-oriented hydrologic models to the larger scale water balance models necessary to define and quantify the land phase of GCMs;
5) To analyze the backscattered signals from SIR-C/X-SAR as a function of surface soil moisture, vegetation type, and roughness;
6) To compare theoretical models of microwave backscatter and emission with SIR-C/X-SAR observations, the L-band and C-band airborne polarimeter system, and the L-band push-broom microwave radiometer (PBMR). The PBMR could also estimate the bare-field soil moisture over a large area which could be a secondary source of ground truth data for SIR-C/X-SAR.
7) To conduct water balance studies of two regions of limited area, one vegetated and one bare.
J. Dozier
University of California - Santa Barbara
H. Rott
University of Innsbruck
The major goal of the proposed work is to model the spatial distribution of snow surface energy exchange, snow metamorphism, and snow melt in alpine drainage basins. For hydrologic and land surface climate investigations in alpine areas, seasonal snow cover and alpine glaciers are important parameters. Over major portions of the middle and high latitudes, and at high elevations in the tropical latitudes, snow and alpine glaciers are the largest contributors to runoff in rivers and to ground water recharge. Snow and ice also play important interactive roles in the regional climates because snow has a higher albedo than any other natural surface. Understanding processes in the seasonal snow cover is also important for studies of the chemical balance of alpine drainage basins because of translocation of anions and cations within the snowpack and possible concentrated release in the first phases of the melt season.
The instrument site at Mammoth Mountain ski area is on the eastern slope of the south-central Sierra Nevada at an elevation of 2930 m, approximately 50 km northwest of Bishop, California. A snow study plot has been maintained there since 1978. Year-round access to the instrument site is provided by the ski area's gondola and lift system, and summer access by automobile is possible. The site is an open, high altitude area characterized by high winds and dry snow, and is typical of the Sierra Nevada's alpine region. Wind speeds of 30 meters per second are not uncommon. Vegetation is sparse with only a few large trees 50 to 200 meters away. Mean winter air temperature is approximately -5deg.C, and mean annual maximum snow water equivalent is about 0.8 m. Snowfall usually begins in early November, and the snowpack often persists well into May. The site is instrumented with complete automatic meteorological capabilities, radiometers, a snow pillow, and snow lysimeters. At this site, it is possible to carry out a complete energy budget from the beginning of the accumulation season until the end of the snow melt season.
S. Vetrella
University of Naples
Despite the considerable number of variables that contribute to SIR-C/X-SAR image formation, the data can reveal system descriptors by studying the system response to known point or extended targets within the scene. Even if restricted to SAR application on land, it can be stated that the only effective calibration is one performed at the total system level, e.g. from input scene to output image or from input spectra to output spectra. The ultimate justification of this study is to prove the effectiveness of calibration to provide the end-users with consistent data-sets.
This test site in southern Italy, near Matera, was chosen because it offers several advantages. A new National Research Council Institute, devoted to space activities and connected to the National Space Plan, has been completed in this area. In December 1987, SAR processing activities started in this research center where a Laser Ranging Station has been fully operative since 1985. Further advantages are: 1) the existence of detailed and current topographic surveys for the area; 2) the proximity of powerful computing facilities; 3) the foreseen SAR Processing Facilities that could process SIR-C/X-SAR raw data; 4) public and private institutions in the area conducting environmental and agricultural studies; and 5) the morphological and land cover characteristics of the area.
W. Alpers
Universitat Hamburg
SIR-C/X-SAR experiments in the North Sea involve measuring ocean wave spectra and mapping sea bottom topography.
Two-dimensional ocean wave spectra will be measured using a pitch and roll buoy from a German Hydrographic Office ship located in the North Sea. There will also be collaboration with North Sea oil rig operators to obtain wave spectra from these sites.
In addition to these in-situ measurements of ocean wave spectra, a third generation wave prediction model, called the WAMODEL, will be applied to forecast, resp. hindcast, the wavefields in the North Sea from the measured wind history during the SIR-C overflight. The two-dimensional wave spectra measured by the buoys and calculated from the WAMODEL over the entire North Sea (and Atlantic) will be compared with the X-, C- and L-band SAR image intensity spectra of SIR-C/X-SAR.
The second experiment will investigate the possibilities and limitations of mapping sea bottom topography with SIR-C/X-SAR imagery. Detailed knowledge of shallow sea bottom topography is important for studying coastal zone management, coastal erosion, environmental development, operational guidance of shipping traffic, fisheries and offshore activities. This work will be conducted in collarboration with Delft Hydraulics (Netherlands) and Gordon Keyte.
Radar images have great potential for revealing large scale horizontal structures including underwater banks and sand waves. Although no accurate depth information can be obtained from SAR imagery, it does provide a synoptic view of a large area. Such overviews are useful to select spatial and temporal sampling of the region involved and are an indispensable tool for optimizing bathymetric surveys.
There is a broad consensus that imaging of sea bottom topography is due to modulation of surface roughness by the interaction of tidal currents and sea bottom topography. It is likely that radar images revealing sea bottom topography can provide information about the dynamic behavior and evolution of bottom structures.
G. Taylor
University of New South Wales
A. Freeman
JPL
C. Rapley
University College London
Three different experiments will be carried out at the Palm Valley test site during SIR-C/X-SAR.
The University of New South Wales will be conducting an experiment to: 1) Assess the utility of multipolarization, multifrequency spaceborne radar for surficial sediment mapping and groundwater management in an Australian environment; and 2) establish the utility of the SIR-C/X-SAR imagery for recognizing basement structures by mapping drape-related fractures in overlying surficial sediments.
The University College London will be conducting an experiment to: 1) Carry out a technical and geophysical investigation of scanning-beam, beam-limited altimetry using SIR-C/X-SAR at vertical incidence over a well-characterized desert test site; 2) evaluate and compare the height information obtainable by means of SAR interferometry and SAR stereo over the test site; 3) obtain multifrequency, multipolarization, multilook angle SAR images of the test site covering several surface types in order to investigate the surface and subsurface features and properties which can be measured and to define optimum observing parameters; and 4) evaluate the role of satellite remote sensing in general, and satellite altimetry and SAR in particular, in improving the understanding of the geomorphological processes of erosion, transportation and deposition in arid regions. To develop and validate analysis techniques with global applicability for the study and monitoring of desert processes, particularly those associated with climate change.
The third experiment is a calibration experiment and will be carried out by the Jet Propulsion Laboratory. This experiment will entail the deployment of corner reflectors for the radiometric and geometric calibration of the SIR-C/X-SAR data obtained at this site.
Prince Albert, Saskatchewan, Canada
K. Jon Ranson
Goddard Space Flight Center
Prince Albert, Saskatchewan is one of the study sites chosen for the Boreal Ecosystem - Atmosphere Study (BOREAS). The goal of BOREAS is to obtain an improved understanding of the interactions between the boreal forest biome and the atmosphere in order to clarify their roles in global change.
Specific objectives are: 1) Improve our understanding of the processes which govern the exchanges of energy, water, heat, carbon, and trace gases between boreal forest ecosystems and the atmosphere, with particular reference to those that may be sensitive to global change; and 2) to develop and validate remote sensing algorithms for transferring our understanding of the above processes from local to regional scales. In particular, BOREAS will address three major scientific issues: 1) the biogeochemical functioning of the boreal forest, including controls on carbon storage and partitioning and the seasonal and spatial variability of trace gas fluxes; 2) the sensitivity of the boreal forest biome to changes in the physical climate system; and 3) the biophysical feedbacks to the climate system due to ecological changes in the functioning of the biome.
Primary forest types in the two areas include aspen, jack pine, and black spruce. Extensive biophysical measurements and remote sensing observations of several forest stands are planned as part of BOREAS. Overflights of the JPL AIRSAR and AVIRIS instruments are planned for August 1993 and during several intensive field campaigns during 1994.
M. Fujita
Communications Research Laboratory
A like- and cross-polarization experiment will be conducted at this site. Both active (C-band) and passive radar reflectors will be deployed and used as standard reflectors having known radar cross sections. One of the active reflectors is capable of shifting the frequency of the re-transmitting signal, and hence it's SAR image will move in azimuth direction relative to it's background. The signal strength of the SIR-C C-band wave will be measured for SAR antenna pattern measurements. Independent measurements of backscatter coefficients will be made at the site for comparison with the satellite estimate.
A. Dabbagh
King Fahd University of Petroleum & Minerals
The investigations for the Saudi Arabian test site will use SIR-C/X-SAR imagery to detail the geological formation boundaries and distinctive lithologies within the Kingdom of Saudi Arabia, both from each other and where they are often covered by shallow sand or soil. This will be applied to the major sedimentary basins of Saudi Arabia in the north, east, and southwest of the country, which form the most important prospective areas for reserves of oil, gas, and water. For these investigations, dual frequency L-band (23 cm) and C-band (6 cm), multipolarization, SIR-C radar imagery, together with dual band X-SAR images offers the most potential.
In addition, large areas of chemical sediments, especially gypsum and halite, will be distinguished by their different surface roughness using multiple polarization capabilities so that large areas of sabhka within the Kingdom can be mapped and their sediments distinguished.
VI. SIR-C/X-SAR SCIENCE TEAM and INVESTIGATIONS
Dr. Werner Alpers Co-Investigators:
Institute for Meereskunde H. Masuko Radio Research Laboratory Troplowitzstr. 7 Paolo Trivero Istituto di Cosmogeofisica
D-22529, Hamburg
GERMANY
Comparison of SIR-C Simulated and Measured SIR-C SAR Image Spectra with Ocean Wave Spectra Derived from Buoys and Wave Production Models in the North Sea
I. OBJECTIVES
a) Carry out measurements of two-dimensional ocean wave spectra by a pitch and roll buoy from the Forschungsplatform Nordsee (German Research Platform North Sea) and from a ship of the German Hydrographic Office in the North Sea. Collaborate with of North Sea oil rig operators to obtain wave spectra from these sites.
b) A third generation wave prediction model (WAMODEL) will be applied to forecast, respectively hindcast, the wavefields in the North Sea from the measured wind history during the SIR-C overflight. The WAMODEL has a resolution of 0.5 degrees longitude and 0.25 degrees latitude. This model (Komen and Zambreski, 1986; Bauer et al., 1988) seems to be accurate in predicting two-dimensional ocean wave spectra in the North Sea and will be refined for the SIR-C mission.
II. APPROACH
a) Compare two-dimensional wave spectra measured by buoys and calculated from the wave prediction model (WAMODEL) over the entire North Sea (and Atlantic) with the X-, C-, and L-Band SAR image intensity spectra of SIR-C.
b) Apply SAR imaging theory (Alpers and Rufenach, 1979, Alpers et al., 1981; Alpers, 1983; Alpers and Bruning, 1988; Alpers et al., 1986; Bruning et al., 1988a, 1988b) to the measured and predicted ocean wave spectra to predict the X-, C-, and L-Band SAR image spectra of SIR-C.
III. ANTICIPATED RESULTS
a) Determine the accuracy of the SAR wave imaging theory to both measured and predicted ocean wave spectra in the North Sea.
b) Determination of the optimum hydrologic and meterologic conditions for routine mapping of sea bottom topography using SAR data.
c) Determination of the optimum radar parameters for routine mapping of sea bottom topography.
Mr. Robert C. Beal Co-Investigators:
The Johns Hopkins University Thomas W. Gerling Applied Physics Laboratory
Applied Physics Laboratory Frank M. Monaldo Applied Physics Laboratory
Johns Hopkins Road
Laurel, MD 20707-6099
Wave Dynamics in the Southern Ocean
I. OBJECTIVES
a) Construct a spatially continuous daily estimate of the directional wave energy transport across the only pure ocean circumpolar route on the planet, a route that is just to the south of the net source function (i.e., south of the maximum wind zone).
b) Determine the temporal and spatial variability of the directional wave transport in the study area over the mission.
II. APPROACH
a) Collect a total of 96 three-minute data-takes with C-band HH polarization, south-looking at 25deg. incidence angle. This geometry will permit the acquisition of a contiguous sequence of six complete circumpolar data sets at 58deg.S, nearly centered on the narrow Drake passage.
III. ANTICIPATED RESULTS
From this data set, and by extending our L-band algorithms developed and verified with SIR-B, we will:
a) Estimate the angular distribution of total wave energy flux through the 58deg.S latitude circle and partition the total energy into sixteen 22.5deg. longitude zones;
b) Determine the temporal and spatial variability of the directional wave energy transport in each of the 22.5deg. zones over the total mission duration; and
c) Calculate the angular distribution of total wave energy transport versus longitude by normalizing the (relative) spectra with the mean monthly wave height determined from Geosat altimeter averages, which are essentially invariant from year to year (based on 1985 to 1987 data).
Dr. R. J. Brown Co-Investigators:
Applications Technology Div. H. Gwyn University of Sherbrook
Centre for Remote Sensing T. Pultz Canada Ctr. for Remote Sensing
4th Floor, 1547 Meridian Rd K.P.B. Thomson Laval University
Ottawa, Ontario K1A 0Y7
CANADA
Multi-Incidence Angle/Multi-Frequency Effect in Satellite SAR Imagery Pertaining to Vegetation Characterization and Hydrology
I. OBJECTIVES
a) Evaluate the range of incidence angles over which radar backscatter is predominately from the underlying soil, the vegetation canopy, and a combination of the two as a function of frequency and polarization; develop models to characterize the backscatter.
b) Evaluate the synergism of VIR and SIR-C/X-SAR data for crop type discrimination and as an input to remote sensing/meteorological crop yield models.
c) Evaluate SIR-C/X-SAR data for soil moisture and as an input to watershed run-off prediction models.
II. APPROACH
a) Acquisition of multi-frequency, multi-incidence angle, multi-polarization SIR-C/X-SAR data in a summer month for vegetation condition and soil moisture assessment, and in a winter month for assessment of snowpack characteristics.
b) Use ARCs and a ground-based scatterometer for absolute calibration of SIR-C/X-SAR imagery.
c) Collect airborne SAR, satellite VIR imagery, and intensive ground data collection to support SIR-C/X-SAR data.
d) Statistical and graphical evaluation of summer SIR-C imagery to isolate changes in backscatter as functions of frequency, incidence angle, and polarization; identify optimum imaging parameters for vegetation characterization and soil moisture assessment.
e) Statistical comparison of near-coincident and temporally different SAR and VIR imagery to determine the degree of synergism/redundancy between the two data types for crop discrimination and condition assessment.
f) Introduction of SAR and VIR imagery (alone and in combination) as surrogates for Leaf Area Index (LAI) in crop yield models and for soil moisture in watershed runoff hydrologic models.
g) Statistical and graphical evaluation of winter SIR-C imagery for snowpack characteristics; assess the feasibility of using SAR imagery as an input to watershed runoff models during periods of snow melt.
III. ANTICIPATED RESULTS
a) At L-band and at small incidence angles for X- and C-band the radar backscatter will be predominantly correlated to soil parameters.
b) Crop yield model performance will improve with the introduction of SAR radar backscatter values as a surrogate for LAI.
c) SAR and VIR data used together will improve crop discrimination over the use of VIR data acquired at a non-optimal period in vegetation development.
d) SAR data will be highly correlated to soil moisture at small incidence angles and, as an input to watershed runoff models, will improve the predictions.
Dr. Paolo Canuti Co-Investigators:
Dip. di Scienze della Terra H. Bork Univ. Braunschweig
University of Florence S. Paloscia CNR-IROE, Florence, Italy
Via La Pira, 4 A. S. Ramoorthi NRSA
50100 Firenze
ITALY
Contribution of SAR for Estimating Soil Erosion
I. OBJECTIVE
a) This research aims to evaluate SAR potential in the study of soil erosion problems.
b) Investigate the contributions of SAR images in reconstructing different stages of transport and redeposition of material on watershed slopes, using models which take into consideration several parameters of soil surface (moisture content, roughness, vegetation cover, etc.) that can be extracted from radar backscattering.
II. APPROACH
a) Extraction of hydrological parameters from SAR data.
b) Validation of erosion models based on SAR data.
c) During the SIR-C/X-SAR mission, the following ground truth parameters will be measured in two sub-areas of the Montespertoli test site chosen for detailed experiments:
Soil Measurements:
-soil moisture content (gravimetric and volumetric) at different depths (5, 10, and 20 cm) using hand augers and in different parts of each field;
-dielectric constant of soils using dielectric probes at different frequencies;
-surface soil roughness, expressed as standard deviation of the heights (hstd and correlation length;
-soil temperature at ~5 cm by a thermometric probe.
Vegetation Measurements:
-crop classification (crop type, variety), height and density of plants;
-sowing date, phenological stage of plants, crop conditions, % weed cover;
-number and dimension (length and width) of leaves, diameter of stems, leaf area index;
-plant water content (kg/m2) computed as the difference between fresh and dry weight of different plant constituents (leaves, stems, ears, etc.).
d) Selected measurements (soil moisture, crop classification, phenological stage, plant height and density) will be carried out over the whole area. Sediment transport measurements will be made at the measuring station on the Virginio stream. Texture and other soil characteristics have already been determined.
e) A digital terrain model (DTM) has been prepared for some areas of Pesa and Virginio basins and some meteorological data are available from three meteorological stations in the area.
III. ANTICIPATED RESULTS
a) Quantitative assessment of the relative contribution of soil and different types of vegetation to the backscattering coefficient.
b) Map geological and erosional features from radar images.
c) Estimate geophysical parameters which are involved in the hydrological cycle (i.e., soil moisture, soil surface roughness, vegetation biomass, etc.).
d) Test and validate models to describe soil erosion processes at basin scale which can use SAR data as inputs.
Dr. Ralph Cordey Co-Investigators:
Marconi Research Centre G. E. Keyte DRA, Farnborough
GEC Research Limited J. R. Baker British National Space Centre
West Hannigfield Road S. Quegan University of Sheffield
Great Baddow G. M. Foody University of Swansea
Essex, CM2 8HN N. J. Veck National Remote Sensing Centre
United Kingdom A. Wielogorska Hunting Technical Services
A Study of the Potential of Multi-component SAR Imagery for Agricultural and Forestry Studies
I. OBJECTIVES
a) The objective of this study is to develop the methods to fully exploit multi-component SAR datasets of agricultural and forestry areas.
b) Determine the radiometric information content of multi-component SAR imagery of agricultural and forested areas by developing backscatter models.
c) Develop techniques for the derivation of specific target information from a multi-component dataset, and consequently determine the optimum set of measurement parameters for use in specifying future SAR missions.
d) Develop improved image processing techniques for the extraction of specific image attributes from these images.
II. APPROACH
a) Obtain multi-polarization images at L- and C-band, and single polarization at X-band, at two incidence angles over the well established Feltwell test site in the UK.
b) Carry out simultaneous ground truth measurements to provide environmental soil, crop, and forest parameters.
c) Provide precise calibration of the SAR images using a combination of ground-based scatterometers and active and passive radar targets.
d) Use statistical, empirical, and semi-theoretical models of radar backscatter to define the radiometric information content of the imagery and to develop data extraction techniques relevant to agricultural and forested areas.
III. ANTICIPATED RESULTS
a) A test of the validity of the use of backscatter models developed from ground and aircraft measurements for representing the measurements from a multi-polarization spaceborne SAR.
b) Development of improved processing tools for extracting information from multi-component SAR images over agricultural and forested areas.
c) Assessment of the effectiveness of a variety of ground based techniques for calibrating spaceborne SAR images.
d) Determination of the optimum SAR measurement parameters and preliminary techniques for monitoring and classifying agricultural and forested areas.
Dr. Abdallah Essa Dabbagh Co-Investigators:
Research Institute Dr. K. Al-Hinai King Fahd University
King Fahd University of Dr. H. S. Edgell King Fahd University
Petroleum and Minerals Mr. M. Khan King Fahd University
Dhahran 31261
SAUDI ARABIA
Geologic and Hydrologic Studies of Saudi Arabia under the Shuttle Imaging Radar (SIR-C) Science Plan
I. OBJECTIVES
a) Use SAR imagery to detect lithological boundaries, distinguish tectonic features, map fluvial geomorphology, and elucidate hydrologic systems within larger areas of Saudi Arabia having a thin sand cover.
b) Establish the Pleistocene paleodrainage system of Saudi Arabia with implications for the hydrology of the country and possibly for archeological geology.
c) Assess the effects of sand terrain diversities on backscatter intensity as a function of radar parameters.
II. APPROACH
a) Multiple polarization radar data is needed from SIR-C/X-SAR to determine buried formation boundaries and discriminate lithologic boundaries, lithologic units, and chemical sediments.
b) Use as broad a swath as possible to distinguish tectonic features, fluvial geomorphology, and hydrologic aspects of paleodrainage.
c) Field observations will be carried out to collect ground truth data on joint systems, fold structures, fault systems, rock types, thickness of sand layer over paleodrainages, dune dimensions and orientation, and vegetation density.
III. ANTICIPATED RESULTS
a) Analysis of SIR-C and X-SAR radar imagery is expected to yield spectacular new information on the geology and hydrology of Saudi Arabia.
b) Major revisions and additions to the existing geological map (USGS Misc. Map 1-270A) and quadrangle maps will be made.
c) Significant new data will be obtained on joint systems and fold structures, as well as some of the major fault systems of Saudi Arabia (e.g., the presently poorly defined east Red Sea Fault, the controversial transcurrent movement on the Najd Fault, and the Amar-Idsas Fault).
d) Establishment of the Pleistocene paleodrainage systems of Saudi Arabia has major implications for Saudi Arabian hydrology. In addition, we expect to be able to contribute to the archeological geology of Saudi Arabia by way of ancient irrigation channels and now buried settlements.
e) Determination of optimum radar parameters for identification and delineation of aeolian bedforms.
Dr. Frank Davis Co-Investigators:
Center for Remote Sensing John Melack Univ. of Calif., Santa Barbara
and Environmental Optics Jack F. Paris California State Univ., Fresno
University of California
Santa Barbara, CA 93106
Biomass Modeling of the Ponderosa Pine Forests of Western North America with SIR-C/X-SAR for Input to Ecosystems Models
I. OBJECTIVES
a) Integrate existing forest biophysical measurements in our Mount Shasta test site with calibrated aircraft SAR for development and testing of our forest radar backscatter model in Ponderosa pine forests.
b) In collaboration with Kaschiske (a SIR-C/X-SAR PI) and Christensen, integrate forest biophysical measurements from Duke Experiment Forest and calibrated SIR-C/X-SAR images for model application to loblolly pine forests.
c) Apply model to identify major backscattering components from conifer forests at X-, C-, and L-band and at four polarizations.
d) Develop an algorithm to retrieve forest biomass and structure from SAR images.
II. APPROACH
a) Develop a scattering model of individual trees based on extensive scatterometer and dielectric field measurements. This model should be able to predict the major scattering characteristics of a tree as a single scatterer from its DBH, height, crown structure, dielectric constants, and surface roughness of major components of the tree.
b) Extend our composite microwave backscatter model to include a scene model of forest stands of different densities with backscattering sub-models including both a single tree scattering model and an aggregate model of groups of trees within pixels.
c) Test this composite model by using aircraft imaging radar polarimetry data through: 1) identifying the dominant scatterers in an image configuration from both model prediction and image analysis; 2) comparing the predicted means, variances, and statistical dispersion of backscattering coefficients of test forest stands with actual image data; and 3) estimating forest biophysical parameter through inversion.
d) Test the robustness of our model through sensitivity analysis.
e) Aircraft and spacecraft radar images will be processed to: 1) reduce the illumination effect, speckle, and the angular behavior of backscattering from forests for classification alone or combined with TM images; and 2) enable regression against biophysical parameters of forest stands including tree number, tree height, DBH, and biomass of components of trees.
III. ANTICIPATED RESULTS
a) Further our understanding of the microwave scattering mechanisms of forests with respect to radar wavelength, polarization, and incidence angle with special emphasis on estimation of above-ground biomass with respect to magnitude, patchiness, partitioning, spatial distribution, and height distribution.
b) Provide methods to quantitatively estimate biophysical parameters of forest stands from SAR images as input to a spatially-distributed ecosystem model of western pine forests.
Dr. Jeff Dozier Co-Investigators:
Computer Systems Laboratory A.T.C. Chang Lab. for Terrestrial Physics
Center for Remote Sensing and Walter Good Inst. fur Schnee-und
Environmental Optics Lawinenforschung
University of California Klaus I. Itten Geographisches Institut
Santa Barbara, CA 93106 Christian Matzler Inst. fur Angewandte Physik
Shi Yafeng Inst. of Glaciology and Geocry.
Wan Zheng-ming Inst. of Remote Sensing Apps.
SIR-C Investigations of Snow Properties in Alpine Terrain
I. OBJECTIVES
a) Estimate snow-covered area and distribution of snow water equivalence over alpine drainage basins. Surface material may be trees that are taller than the snow depth, brush or grass that will be covered by the snow, soil, scree, talus or bedrock, or glacier ice.
b) Estimate spectral albedo of snow cover.
c) Model spatial distribution of snow surface energy exchange, melt rate, and snow metamorphism intensively during two-to-four-week periods around SIR-C/X-SAR flights, and less intensively during rest of snow season.
II. APPROACH
a) Use three frequencies on SIR-C/X-SAR to estimate snow water equivalence for dry snow and possibly for wet snow. Use co-registered digital elevation data, derived from low-altitude aerial photographs, from SPOT stereographic coverage, or contour maps, to correct for topographic effects in radar data. Validate measurements with intensive snow surveys coincident with SIR-C flights, and with scatterometer measurements at one site. To insure that results are not site-specific, field and satellite investigations will be carried out in three different mountain ranges with different climates: Sierra Nevada (California), Swiss Alps, and Tien Shan (Xinjiang, northwest China). We also plan to acquire satellite data, but no field measurement s, for a test site in the Himalaya (Tibet, southwest China).
b) Use optical sensor data to estimate grain size of surface snow layer and its contamination by impurities (e.g. dust or soot). Use these parameters to extend albedo throughout the solar spectrum. AVIRIS data will be requested for US. sites and Landsat data for foreign sites.
c) Use frequencies from SIR-C/X-SAR, especially 9.6 GHz, to detect wet snow and estimate liquid-water content, and possibly to identify dry snowpacks with a wet surface layer and wet snowpacks with a dry surface layer.
d) Use satellite or aircraft data, local micrometeorological data, and digital elevation grids to derive basin-wide energy balance model of snowpack.
III. ANTICIPATED RESULTS
a) Evaluate the ability to continuously monitor and model processes in the Earth's alpine snow cover, thus demonstrating the possibility of achieving an important objective that could be supported by the Earth Observing System (EOS).
b) SIR-C measurements of the snow cover will be carefully calibrated with physical measurements of snow characteristics, thus providing excellent data for evaluation of models of the electromagnetic properties of snow.
Dr. Edwin T. Engman Co-Investigators:
NASA/Goddard Space Flight Center Thomas J. Jackson USDA/Agr. Res. Service
Greenbelt, MD 20771 William Kustas USDA/Agr. Res. Service
Peggy O'Neill Goddard Space Flight Center
Thomas Schmugge USDA/Agr. Res. Service
Eric F. Wood Princeton University
Applications of SIR-C Synthetic Aperture Radar to Hydrology
I. OBJECTIVES
a) Determine and compare soil moisture patterns within one or more humid watersheds using SAR data, ground based measurements, and hydrologic modeling.
b) Use radar data to characterize the hydrologic regime within a catchment and to identify the runoff producing characteristics of humid zone watersheds.
c) Use radar data as the basis for scaling up from small scale, near-point process models to larger scale water balance models necessary to define and quantify the land phase of GCMs.
II. APPROACH
a) Select and evaluate hydrologic models capable of simulating hillslope flow process and spatially distributed soil moisture.
b) Collect hydrologic data and spatial soil moisture through a ground data collection program during the SIR-C flights.
c) Convert SAR data to estimates of soil moisture in the presence of a vegetation layer through inversion of microwave backscatter models.
d) Compare the three independent estimates of soil moisture (SIR-C derived, model-derived, and ground-data) to evaluate the utility of the SIR-C data.
e) Use radar derived soil moisture data to calibrate models to depict larger scale processes.
III. ANTICIPATED RESULTS
a) Develop a technology for measuring soil moisture in natural catchments for humid regions using spaceborne radar.
b) Develop a new way to characterize the contributing areas of natural, humid zone catchments.
c) Develop a technology for modeling soil moisture distributions in natural catchments based on spaceborne measured data.
d) Develop procedures for parameterizing macro-scale models capable of representing the land phase processes for GCMs.
e) Development of procedures to scale up hydrologic processes from point or small area to catchment scales using SAR data.
f) Validation of vegetation models for estimating the backscatter component of overlying vegetation canopies and the underlying soil condition.
Dr. Tom G. Farr Co-Investigators:
Mail Stop 300-233 William Bull University of Arizona
Jet Propulsion Laboratory Oliver Chadwick Jet Propulsion Laboratory
4800 Oak Grove Drive Diane Evans Jet Propulsion Laboratory
Pasadena, CA 91109 Alan Gillespie University of Washington
Gilles Peltzer University of Paris
Paul Tapponnier University of Paris
Climate Change and Neotectonic History of Northwestern China
I. OBJECTIVES
The goal of the proposed research is to determine the history of Quaternary climate change for a portion of northwestern China for inclusion in global paleoclimate models and reconstructions of the tectonic history of the area and specifically, to:
a) Determine the extended spectral signatures of desert surfaces and landforms of different ages in a few test sites in northwestern China.
b) Use these signatures to map surfaces and landforms related to past climate changes and determine the history of Quaternary climate change.
b) Determine the ages of movements on some of the active faults in northwestern China.
c) Compare surface modification processes that have operated in northwestern China to those in the southwest US.
II. APPROACH
a) Establish a few key "calibration" sites at which ages of geomorphic surfaces will be determined, remote sensing signatures of the surfaces measured, and the variation of surfaces between and within drainage basins examined.
b) Correlate and map geomorphic surfaces over an extended area of northwestern China, using SIR-C, Landsat, and SPOT data to assist in the derivation of a regional paleoclimate chronology.
c) Use maps of geomorphic surfaces to constrain the tectonic histories of one or more faults passing through the area.
d) Compare with results from similar studies in the arid southwest United States.
III. ANTICIPATED RESULTS
a) Maps of geomorphic surfaces with ages attached to them will be a major step toward understanding the climatic history of this region.
b) Comparisons of this climate record with climate records from the oceans and other continents will help advance the global synthesis of climate change.
c) Determination of how unique and how globally representative remote sensing signatures are will directly affect our future ability to extrapolate the signatures to global studies of climate change. Determination of past slip rates on some active faults in northwest China by a knowledge of the ages of offset surfaces.
Dr. Pierre Flament Co-Investigators:
Hawaii Institute of Geophysics Hans C. Graber Woods Hole Oceanog. Inst.
University of Hawaii at Manoa D. Halpern Jet Propulsion Laboratory
1000 Pope Road B. Holt Jet Propulsion Laboratory
Honolulu, HI 96822
Reconstruction of the Mesoscale Velocity Shear Seaward of Coastal Upwelling Regions from the Refraction of the Surface Wave Field
I. OBJECTIVES
a) Develop an inverse model of the surface velocity from the refraction of surface waves observed on SAR images.
b) Study the limitations of the model owing to total reflection and caustics.
c) Apply the model to study the small-scale velocity structure of upwelling filaments.
II. APPROACH
a) Collect pairs of crossing SAR images to reduce the errors due to azimuth smearing.
b) Compute surface height spectra from the images, identify wavetrains in the spectra, and use the inverse model to compute the velocity field.
c) Compare the results with co-located NOAA infrared images and shuttle hand-held photographs.
III. ANTICIPATED RESULTS
a) Information on the shear distribution of the filaments, and its correlation with wind speed and wave height which is difficult to obtain from in situ measurements.
b) Information on wind inhomogeneities above the filaments.
c) Comparison of the summertime and wintertime flows and determining whether filaments exist in the winter.
d) Comparison of filament structure in the Northern and Southern hemispheres.
Dr. Anthony Freeman Co-Investigators:
Mail Stop 300-235 M. Craig Dobson University of Michigan
Jet Propulsion Laboratory Peter Hoogeboom TNO Physics & Elec. Lab.
4800 Oak Grove Drive Yuhsyen Shen Jet Propulsion Laboratory
Pasadena, CA 91109 Fawwaz T. Ulaby University of Michigan
Charles L. Werner Jet Propulsion Laboratory
Multi-Frequency, Multi-Polarization External Calibration of the SIR-C/X-SAR Radars
I. OBJECTIVES
a) Assess the accuracy at which the SIR-C/X-SAR standard data products can be calibrated through the use of ground calibrators to estimate the end-to-end system polarization calibration constants (or distortion parameters) and incorporate the constants into the data processing.
b) Study the cross-calibration between three multi-polarization systems: SIR-C, the NASA/JPL DC-8 SAR, and the University of Michigan ground-based polarimetric scatterometer.
c) Evaluate the calibration "stability" of SIR-C/X-SAR (measured by variations in the calibration constants) over the range swath width and over a specified distance in azimuth. Variations over a 12-hour period (between ascending and descending passes) will also be studied.
d) Develop a cost-effective calibration plan including development of inexpensive polarimetric active calibrators.
II. APPROACH
a) Calibrate all the calibrators at standard ranges prior to deployment.
b) Use polarimetric active radar calibrators to estimate end-to-end polarization distortion of the SIR-C system. Use the estimated distortion parameters to extract a "best estimate" of the polarization scattering matrix of other ground targets.
c) Deploy inexpensive trihedral corner reflectors to characterize co-polarized channel imbalance in magnitude and phase over an area wider than that covered by the active calibrators in the primary calibration area.
d) Use multi-polarization ground receivers to record the system transmit azimuth pattern at several elevation cuts and to estimate the transmit polarization distortion. Use calibrated multi-polarization ground scatterometers to provide in situ data over extended targets and compare them with SIR-C/X-SAR data of the same targets. Evolve a cost-effective calibration strategy by comparing the "calibrated'' results obtained using different calibration philosophies.
III. ANTICIPATED RESULTS
a) Full polarimetric end-to-end characterization of the SIR-C/X-SAR system in the primary calibration target area within the limitations of instrument inaccuracy. A better understanding of polarimetric calibration of a space-borne microwave synthetic aperture radar.
b) The polarization scattering matrix of targets within the calibration area will be calibrated to 0.4 dB and 5deg. in magnitude and phase, respectively, between polarization components (or channels) and 2.0 dB absolute error in magnitude, at both L- and C-bands. The compensated absolute error in the X-SAR is expected to be 2.0 dB.
Dr. Masaharu Fujita Co-Investigators:
Communications Research Laboratory Jun Awaka Communications Res. Lab.
4-2-1 Nukuikitamachi Toshio Iguchi Communications Res. Lab.
Koganei-shi, Tokyo 184 Toshio Ihara Communications Res. Lab.
JAPAN Hideyuki Inomata Communications Res. Lab.
Toshiaki Kozu Communications Res. Lab.
Takashi Kurosu Communications Res. Lab.
Takeshi Manabe Communications Res. Lab.
Harunobu Masuko Communications Res. Lab.
Yuji Miyagawa Communications Res. Lab.
Kenji Nakamura Communications Res. Lab.
Takeyuki Ojima Communications Res. Lab.
Ken'ichi Okamoto Communications Res. Lab.
Toshiyuki Okuyama Communications Res. Lab.
Makoto Satake Communications Res. Lab.
Takeshi Suitz Communications Res. Lab.
Toshihiko Umehara Communications Res. Lab.
Seiho Uratsuka Communications Res. Lab.
Like- and Cross-Polarization Calibration, Topographic Mapping and Rice Field Experiments by SIR-C/
X-SAR
I. OBJECTIVES
Three experiments are proposed: (1) Like and cross-polarization calibration, (2) Topographic mapping, and (3) Remote sensing of rice fields. These experiments have the following objectives:
a) To calibrate SIR-C/X-SAR images relating to backscattering coefficient, to estimate 3-dB resolution and to establish a technique for cross-polarization calibration,
b) To investigate the optimal frequency and a technique for image quality improvement for topographic mapping, and
c) To establish techniques for active remote sensing of crops.
II. APPROACH
a) Corner reflectors and active radar reflectors will be used as standard targets. Image data numbers will be related to backscattering coefficients and 3-dB resolution will be estimated from point target images.
b) Topographic estimates will be made from three-frequency images and compared among each other. An effect of image improvement on topographic estimation accuracy will be evaluated.
c) Multi-frequency and -polarization images will be compared and/or combined to determine optimal parameters for crop field detection and identification.
III. ANTICIPATED RESULTS
a) Evaluate the imaging characteristics of SIR-C/X-SAR.
b) Determine the optimal frequency for topographic mapping will be determined and establish a technique for image quality improvement for more accurate topographic mapping.
c) Improved technique for detection and identification of rice and crop fields.
Dr. Alan R. Gillespie Co-Investigators:
Dept. of Geological Sciences AJ-20 John B. Adams University of Washington
University of Washington Milton O. Smith University of Washington
Seattle, WA 98195
Alluvial Fan Evolution in the Western Great Basin
I. OBJECTIVES
a) Describe systematic morphologic changes with surface age in terms of multiparameter radar backscatter for dated chronosequences on alluvial fans at one or two sites in the western Great Basin. Compare these changes to chemical weathering patterns observed for the same fans using visible/near-infrared (VNIR) and thermal infrared (TIR) images.
b) Construct a depositional and weathering history for the studied alluvial fans based on SAR, other images, and field investigations; use this to constrain paleoclimatic interpretations for the Great Basin. Use project as prototype for paleoclimate study of entire Great Basin or other geomorphic provinces, where multiparameter SAR data can be acquired regionally.
c) Test the application of spectral mixing analysis on multiparameter SAR images of alluvial fans in arid and semiarid regions. Define radar endmembers (from the spectral mixing analysis) physically, in terms of Bragg scattering, volume scattering, specular and corner reflectors, and dielectric constant, etc. Develop and test mixing models for comparative analysis of images spanning multiple spectral regions.
II. APPROACH
a) Select study site(s) in Owens Valley/Death Valley to exploit existing geomorphic, soils, and geochronology data, for a sequence of alluvial fans deposited during the last 0.5 Ma.
b) Compare spectral differences in VNIR, TIR, and SIR-C SAR images in terms of systematic chemical and morphological differences predicted by current weathering models, given the known ages of the fan surfaces. Make precise measurements of integrated weathering rates for each dated surface, which can then be analyzed jointly to construct a history of weathering rates and rate changes for selected parameters (e.g., oxidation, hydration, clast disintegration and aeolian silt redistribution).
c) Interpret weathering-rate history in terms of climatic factors that promote weathering (e.g., temperatures, precipitation and excess moisture, wind velocity).
d) Collect and independently analyze VNIR, TIR, and airborne SAR images of the study site(s) prior to the mission to test spectral mixing models applied to radar images alone and with other images.
e) Coregister all SIR-C/X-SAR images to digital terrain models, and jointly analyze them using the "hierarchical" or multi-level spectral mixing model.
f) Separately analyze data from limited spectral regions that are affected by one physical process (e.g., absorption by iron oxide in VNIR data, or scattering due to surface roughness in radar wavelengths). This will be followed by analysis comparing and contrasting results for processes affecting more than one spectral region (e.g., topographic texture affects VNIR data by shading, and affects radar data by scattering).
III. ANTICIPATED RESULTS
a) New technique for "unmixing" multiparameter radar images into meaningful components (e.g., volume-scattering surfaces or "vegetation," Bragg-scattering surfaces, etc.).
b) An alternative to "extended spectral signatures" for joint analysis of disparate images spanning multiple spectral regions.
c) Better history of bajada surface evolution than available from chemical weathering studies alone.
d) Improved knowledge of Pleistocene paleoclimate in the western Great Basin.
e) Test predictive models for climate/paleoclimate and for inferences from paleoecological studies.
Dr. R. M. Goldstein Co-Investigators:
Mail Stop 300-227 A. K. Gabriel Jet Propulsion Laboratory
Jet Propulsion Laboratory Fuk K. Li Jet Propulsion Laboratory
4800 Oak Grove Drive C. L. Werner Jet Propulsion Laboratory
Pasadena, CA 91109 Howard A. Zebker Jet Propulsion Laboratory
Differential Radar Interferometry
I. OBJECTIVES
a) Test differential radar interferometry as a new monitoring technique for remote sensing of a forest site, a farm site, and a desert site.
b) Generate topographic maps of test sites from radar data.
II. APPROACH
a) Apply differential inteferometry with respect to wavelength at the forest test site, and with respect to time at the farm and desert test sites.
b) Obtain ground truth data at each site during the mission including tree height, species, and density at the forest site, activity at the farming site, and tropospheric water vapor at the desert site.
c) Verify the derived topography against available topographic maps of the sites.
III. ANTICIPATED RESULTS
a) Separate topographic maps of the forested site from L- and C-band data. Measurement of canopy height from the difference between these data sets. Use ground truth data to assess the validity of two frequency interferometry for monitoring canopy height in forested areas.
b) Detect changes of less than one centimeter in the surface of the fields at the farm site. Such changes are expected to depend mostly on the moisture content of the fields, through either dielectric constant changes or physical swelling of the surface induced by water.
c) Since surface disturbances at the desert test site are not expected to occur between successive SIR-C overflights, it is expected that phase changes due to changes in local tropospheric water vapor may be detectable by differential interferometry.
d) Assessment of the strengths and weaknesses of topography derived from interferometric SAR data for different types of surfaces/sites.
Dr. Ronald Greeley Co-Investigators:
Department of Geology Dan Blumberg Arizona State University
Arizona State University A. Dobrovolskis NASA Ames Research Center
Tempe, AZ 85287-1404 James Iverson Iowa State University
Nicholas Lancaster Desert Research Center, NV
Bruce White Univ. of California, Davis
Keld Rasmussen Aarhus University
Haim Tsoar Ben Gurion University
Stephen Saunders Jet Propulsion Laboratory
Eilene Theilig Jet Propulsion Laboratory
Stephen Wall Jet Propulsion Laboratory
Howard Zebker Jet Propulsion Laboratory
Development of a Technique to Relate Eolian Roughness to Radar Backscatter Using Multi-Parameter SIR-C Data
I. OBJECTIVES
a) To develop a technique to obtain values of aeolian roughness for geologic surfaces from values of surface roughness determined from calibrated L- and C- band, like- and cross-polarized, multiple incidence angle radar data from SIR-C.
b) To define the optimal combination of radar parameters from which aeolian roughness can be derived.
c) To gain an understanding of the physical processes behind the empirical relationship.
II. APPROACH
a) Extract average backscatter coefficients from SIR-C SAR images for natural desert surfaces important to the study of aeolian processes.
b) Model statistics of surface roughness with other SIR-C investigators using multiple parameter data sets.
c) Compute statistical descriptions of surface roughness from large- (m) and small- (cm) scale topographic profiles measured in the field on each surface.
d) Calculate aeolian roughness (zo) from time averaged wind velocity profiles measured in the field. Correlate radar backscatter coefficients, aeolian roughness values, and statistical measures of surface roughness and use regression analysis to derive a predictive equation from which zo could be determined using radar.
III. ANTICIPATED RESULTS
a) Determination of an empirical relationship between measurements of surface roughness as detected by the wind and microwave energy.
b) Development of an equation expressing this relationship. This expression will form the basis of a technique for using spaceborne SAR data to determine a roughness parameter for use in aeolian sand transport rate equations.
c) Validate models of aeolian response to surface roughness.
Dr. Huadong Guo Co-Investigators:
Institute of Remote Sensing Applications Li Xiaowen Nat. Remote Sensing Center
Chinese Academy of Sciences Wan Zhengming Nat. Remote Sensing Center
P.O. Box 775
Beijing 100101, CHINA
Evaluation of SIR-C/X-SAR Imagery for Geologic Studies in China
I. OBJECTIVES
a) Conduct a radar penetration study by measurement of typical surficial covers.
b) Develop theoretical modeling of radar scattering for penetration study.
c) Develop a limited inversion of radar scattering model for applications of SIR-C/X-SAR data.
II. APPROACH
a) Development of a radar scattering model for realistic and simple surficial cover or layers.
b) Conduct systematic field measurements under controlled conditions.
c) Perform airborne measurements over the study areas with the Chinese X-band, quad polarization SAR system.
d) Analyze field and SAR data by a rational combination of physical modeling, statistical modeling, and measurements.
III. ANTICIPATED RESULTS
a) Theoretical/experimental dependence of radar penetration depth on wavelength, polarization, incidence angle, and properties of the medium.
b) Geologic maps over test areas of China based on multiband, multipolarization SIR-C/X-SAR data.
c) Evaluation of the quantitative applications of SIR-C/X-SAR data in combination with satellite and other ancillary data.
Dr. Franz Heel Co-Investigators:
Institut fur Hochfrequenztechnik H. Kietzmann DLR, Oberpfaffenhofen
DLR - Oberpfaffenhofen J. Nithack DLR, Oberpfaffenhofen
D Wessling M. Reich Inst. fur Navigation, Stuttgart
GERMANY
X-SAR/SIR-C Radiometric Calibration Experiment
I. OBJECTIVES
a) The main objectives of the DLR/INS experiments are to determine error sources and assess their contributions on the absolute calibration accuracy of the overall system.
II. APPROACH
A series of five different experiments covering internal and external procedures are planned. Oberpfaffenhofen and its surrounding area will serve as a master test site. The five experiments are: 1) Internal calibration; 2) Measurement of operational SAR antenna pattern; 3) Absolute calibration of SAR image data; 4) Mutual radiative coupling of clutter surrounded calibration targets; and 5) Attenuation of microwaves caused by woodlands.
III. ANTICIPATED RESULTS
a) Quantify the sensor impacts on signal quality and separate systematic from statistical error contributions. Systematic errors will be corrected.
b) Comparison of ground truth antenna patterns with predetermined patterns to assess changes due to Shuttle interference, thermal effects, and incomplete deployment.
c) Development of a procedure to scale the intensities of different earth surface object classes in terms of absolute backscatter values.
d) Assessment of the effects of mutual radiative coupling between closely spaced calibration targets.
e) Investigation of the attenuation effects of forests on SAR signals leading to a better understanding of forest SAR signatures.
Dr. Bryan Isacks Co-Investigator:
Department of Geological Sciences Arthur L. Bloom Cornell University
Snee Hall
Cornell University
Ithaca, NY 14853
SIR-C Analysis of Topography and Climate in the Central Andes
I. OBJECTIVES
a) Understand large-scale interactions between tectonic and climatic-controlled erosional processes that created the Andes.
b) Determine the modern and Pleistocene snow-line altitudes and gradients in a poorly known but critical latitude range of the central Andes, and interpret ice-age changes in atmospheric circulation.
II. APPROACH
a) Acquire four adjacent ascending swaths of SIR-C radar imagery, each with at least two look angles, over the central Andes between 23deg. S and 33deg. S.
b) Compile a digital elevation model (DEM) for this poorly mapped region from multi-frequency, dual-polarization SIR-C data.
c) Use the DEM to study heretofore inaccessible mesoscale (10m-10km) topography in relation to spatial variations of rates of erosion and uplift needed to calibrate geophysical models of Andean mountain building.
d) Analyze radar surface-roughness variations on glacial and volcanic landforms in the central Andes, using ground measurements of slopes to correct for backscatter variations by local incidence angles.
e) Integrate SIR-C data into ongoing field research and Landsat TM analysis of Andean relief.
III. ANTICIPATED RESULTS
a) A new understanding of orogenic relief over a large range of spatial frequencies and of the relative importance of tectonic, volcanic, and erosional processes in shaping landforms of different characteristic wavelengths.
b) A useful new digital elevation model of a poorly known region, to combine with LANDSAT TM and field research in ongoing research.
c) A test of climatic change theories concerning the equatorward shift of the southern hemisphere atmospheric circulation over the Andes during ice ages.
Dr. Arthur R. Jameson
Applied Research Corporation
8201 Corporate Drive, Suite 920
Landover, MD 20785
The Joint Analyses of Single-and Dual-Frequency/Experimental Dual-Polarization
SIR-C and X-SAR Measurements in Precipitation
I. OBJECTIVES
a) Determine the vertical and horizontal spatial distribution of hydrometeors in precipitating clouds. Measure the spatial distribution of liquid water and ice in the clouds.
b) Measure and determine the limits of measurement of the polarization characteristics related to the shapes and orientations of hydrometeors in precipitating clouds.
II. APPROACH
a) SIR-C/X-SAR data will be used to determine the total attenuation from precipitation using the signal strength reflected from the earth's surface. This information will be used as a constraint on the radar equation to provide profiles of the extinction cross-section.
b) Data from SIR-C/X-SAR will be used to remove the effect of partial beam filling, to estimate the vertical distribution of the hydrometeors phase, and to provide an independent estimate of the total path extinction. (The results from c) will then be applied to the steps cited in a) and b.)
c) Collect polarization measurements over a wide range of nadir angles to determine the feasibility and limitations for space measurements of differential reflectivity, linear depolarization, and propagation differential phase shift.
d) To more fully understand the precipitation, we will use passive microwave measurements to analyze in conjunction with the radar data.
e) Validate the spatial distribution of rain by (in order of descending reliability):
1. Comparison with rain rates derived from calibrated CAPPI digital ground based radar,
2. Comparison with operational NOAA radar imagery that is distributed digitally,
3. Comparison with spatial rain distributions inferred from visible and infra-red imagery from operational NOAA satellites.
III. ANTICIPATED RESULTS
a) Identification of the effects of precipitation on SIR-C/X-SAR surface measurements.
b) Analytical techniques, such as those used to retrieve rainfall from data collected during the Tropical Rainfall Measuring Mission (TRMM), can be studied before the TRMM launch. Those results will have an ultimate impact on the Earth Observing System (EOS) initiative..
c) As the first precipitation polarization measurements from space, these data will help determine the future potential application for global microphysical measurements from space.
d) Unique radar studies of precipitation may be possible since data may be collected over intense convective systems over which aircraft bearing radars have not been able to fly.
Dr. Eric S. Kasischke Co-Investigator:
Radar Science Laboratory Norman Christensen Duke University
ERIM
P.O. Box 8618
Ann Arbor, MI 48107
Estimation of Total Aboveground Biomass in Southern United States Old-Field Pine Stand Using SIR-C/X-SAR Data
I. OBJECTIVES
a) Validate a radar tree scattering model using scatterometer and SAR data collected over old-field loblolly pine stands.
b) Determine what short-term physiological changes within loblolly pine forests result in significant changes in radar backscatter signature.
c) Develop a model that predicts the total aboveground biomass as a function of the multifrequency, multipolarization radar signature.
d) Evaluate utility of biomass estimation algorithm utilizing SIR-C/X-SAR data set.
II. APPROACH
a) Collect multifrequency, multipolarization helicopter-borne scatterometer and/or airborne SAR data sets over old-field loblolly pine stands in Duke University Research Forest during three different seasons and on a diurnal basis.
b) Coincident with radar data collection, collect ground-truth data to physically describe loblolly pine test sites.
c) Compare observed [[sigma]]deg. values to those predicted by a theoretical scattering model.
d) Based on modeling results, develop an algorithm which estimates total aboveground biomass for loblolly pines as a function of the radar signature.
e) Evaluate utility of biomass estimation model using radar data collected by SIR-C/X-SAR over loblolly pine test sites located in southeastern US.
III. ANTICIPATED RESULTS
a) An understanding of what forest characteristics within a loblolly pine forest influence radar scattering at X-, C- and L-band.
b) Validation of a theoretical scattering model for the forest geometry of old-field loblolly pines.
c) An evaluation of the utility of multifrequency, multipolarization for estimating aboveground biomass in old-field loblolly pine forests and other pine forests in the southeast US.
Dr. Gordon Keyte Co-Investigators:
Royal Aerospace Establishment J. P. Matthews University of North Wales
Space & New Concepts Department G. J. Wensink Delft Hydraulics. NAL
Farnborough, Hampshire R. Cordey Marconi Research Centre
ENGLAND
An Investigation of the Imaging of Ocean Waves and Internal Waves with SIR-C/X-SAR
I. OBJECTIVES
a) To improve our understanding of ocean-wave imaging by synthetic-aperture radar (SAR).
b) To test the assumptions of backscattering theory with regard to short-wave properties.
c) To develop new techniques for retrieving ocean-wave spectra from multi-parameter SAR.
II. APPROACH
a) Obtain dual-frequency, dual-polarization SIR-C/X-SAR images at a set of crossing-swath locations.
b) Measure long-wave spectra with an array of wave buoys deployed by a ship.
c) Monitor small-scale waves with a stereo-optical system and possibly a laser slope gauge.
d) Obtain additional SAR imagery at different range-to-velocity ratios from an aircraft and ERS-1 for further study of the effects of wave motions.
III. ANTICIPATED RESULTS
a) An accurate empirical model of the dependence of wave-imaging transfer function on radar frequency, polarization and incidence angle.
b) A greater understanding of the roles of short-wave straining and of scatterer motions in providing mechanisms for imaging long waves.
c) An improved knowledge of conditions under which non-linear imaging limits the wave information recoverable from SAR data.
d) Optimum procedures for recovering wave information and recommendations for SAR-system parameters for future missions.
Prof. Jin A. Kong
Department of Electrical Engineering
Massachusetts Institute of Technology
Cambridge, MA 02139
SIR-C Polarimetric Radar Image Simulation and Interpretation Based on Random Medium Model
I. OBJECTIVES
a) Demonstrate the applicability of the random medium model in simulating SIR-C imagery.
b) Analyze and interpret SIR-C imagery for remote sensing applications.
c) Investigation of seasonal variations and atmospheric effects.
II. APPROACH
a) Use the random medium model, with extensive ground truth data, to simulate SIR-C multi-frequency, multi-incident angle, fully polarimetric imagery and actual SIR-C data.
b) Develop polarimetric classification and contrast algorithms using simulated images based on the random model, then apply these tools to analyze and interpret SIR-C imagery.
c) Effects of seasonal variations and atmospheric conditions will be investigated by extending the random medium model to multi-layer configurations to facilitate the interpretation of SIR-C imagery.
III. ANTICIPATED RESULTS
a) Predicted multi-frequency, multi-incidence angle, fully polarimetric SIR-C imagery prior to the actual SIR-C mission.
b) Interpret SIR-C imagery with applications to vegetation classification, crop type, snow depth, seasonal and diurnal change studies.
c) Radar image simulation algorithm based on the random medium model for future radar sensor development.
d) Improved radar image processing algorithms for terrain classification.
e) Multi-layer random medium model for general earth terrain scattering.
Dr. Fred A. Kruse Co-Investigators:
Center for the Study of Earth from Space Alexander Goetz CSES
Campus Box 449 Franz Leberl VEXCEL
Boulder, CO 80309-0449
Comparative Lithological Mapping Using Multipolarization, Multifrequency Imaging Radar and Multispectral Optical Remote Sensing
I. OBJECTIVES
a) Develop a better understanding of depositional and erosional processes by studying the compositional and geomorphic variation in sedimentary and igneous rocks.
b) Develop a better understanding of the current geomorphic expression of rock surfaces by determining the relationship between lithological variability, weathering, soil development, and vegetation distribution.
c) Use variation in radar backscatter as a function of wavelength, incidence angle, and polarization to characterize the geometry, and indirectly, the composition of rock units.
d) Compare radar characterization with visible/infrared characterization of surface materials for both vegetated and non-vegetated areas.
e) Evaluate multidimensional image processing techniques for analyzing multi-spectral/multipolarization/multi-incidence angle radar data and the utility of precision radargrammetry to improve lithological mapping capabilities. Map the character and distribution of lithological variation with SIR-C/X-SAR data.
f) Provide hands-on radar remote sensing experience to graduate students.
II. APPROACH
a) Field measurements to be collected in situ include geologic maps, surface roughness measurements, dielectric constant measurements, and surface visible/infrared spectral measurements.
b) Ancillary remote sensing data sets will include: AIRSAR data, digital elevation models (DEM), co-registered AVIRIS, TM, and TIMS data, helicopter stereo pairs for selected geomorphic surfaces, and aerial photographs.
c) Use SIR-C/X-SAR data to complement the visible/infrared spectral signatures of specific rock units by characterizing the multispectral/multipolarization/multiple incidence angle radar signatures of rock units by analyzing the effect of surface geometry and composition on radar backscatter as a function of radar polarization and wavelength; and co-registering radar data to visible/near infrared imaging spectrometer data (AVIRIS), Thematic Mapper (TM) data, and Thermal Infrared Multispectral Scanner data (TIMS) to map the distribution and character of surface rock units.
d) Model the relationship(s) between lithological variability, depositional processes, weathering and erosion, soil development, and vegetation distribution.
e) Evaluate multidimensional image processing techniques developed for the analysis of multispectral data sets. Extend the analysis to a regional scale using the SIR-C/X-SAR data.
III. ANTICIPATED RESULTS
a) Detailed regional mapping of lithology and geomorphology that will allow improved interpretation of the geologic history of selected areas in the southwestern United States and northern Sonora, Mexico. An improved understanding of the relations between lithological variation and geomorphic expression of rock surfaces.
b) A better understanding of the relation between multiparameter radar image characteristics to rock, soil, and vegetation physical properties.
c) An improved understanding of the strengths and weaknesses of multi-spectral/multipolarization/multi-incidence angle radar and how it can be used to complement visible/infrared remote sensing data.
d) Innovative image processing algorithms and analysis techniques for multispectral/multipolarization/ multi-incidence angle radar.
Dr. Thuy Le Toan Co-Investigators
Centre d'Etudes Spatiales des Rayonnements P. Hoogeboom Physics and Elect. Lab. TNO
9 Av. Colonel - Roche, B.P. 4346 A. Fiumara Telespazio
31029 Toulouse CEDEX
FRANCE
Relating Radar Backscatter Responses to Woody and Foliar Biomass of Pine Forests
I. OBJECTIVES
a) Demonstrate the use of spaceborne SAR images to detect forest parameters (biomass of different parts of the canopy).
b) Increase the understanding of the interaction between microwaves and vegetation canopies.
II. APPROACH
We propose to use Landes forest, near Bordeaux, South East of France as a test site. Previous work in this area has established an existing dataset. Inversion algorithms developed on the test-site will be applied to SIR-C/X-SAR data acquired on other sites in the world including coniferous forest sites. It is proposed to relate SIR-C/X-SAR data to vegetation parameters and to develop an inversion algorithm as follows:
a) Theoretical model(s) will be developed and validated by experiments performed with airborne and laboratory systems.
b) The output of validated theoretical model(s) will be used :
1. to study the sensitivity of radar backscattering measurements to vegetation parameters;
2. to define validity domains of selected invertible semi-empirical models; and
3. to compute the fitting parameters of semi-empirical models.
c) Inversion algorithms will be developed in specified domains of validity.
d) Applications on SIR-C/X-SAR data.
e) Interactive process to refine the algorithm.
III. ANTICIPATED RESULTS
a) A demonstration of the use of multifrequency, multipolarization, and multi-incidence angle SIR-C/X-SAR data to probe different parts of a forest canopy. Based on past results, we expect to have simple (therefore convertible) models relating the radar responses to total, woody, and foliar biomass of pine forests. These parameters are indicators of forest productivity, tree disease, and stress conditions, and are required for forest and ecosystem monitoring.
Dr. Fuk K. Li Co-Investigators
Jet Propulsion Laboratory David Atlas Jet Propulsion Laboratory
Mail Stop 300-227 Peter H. Hildebrand Natl. Ctr. for Atmospheric Res.
4800 Oak Grove Drive K. Eastwood Im Jet Propulsion Laboratory
Pasadena, CA 91109 Richard K. Moore University of Kansas
Remote Sensing of Precipitation by Spaceborne Synthetic Aperture Radar
I. OBJECTIVES
a) Demonstrate, as a proof-of-concept, quantitative measurements of rainfall intensity from space using SIR-C / X-SAR data.
b) Demonstrate the use of the synthetic aperture technique to improve the along-track spatial resolution in the presence of rainfall velocity dispersion.
c) Determine the mean rainfall velocity by extracting the Doppler spectrum centroid relative to the surface returns.
d) Study the backscattering and polarization characteristics of the ocean surface echoes at L-, C- and X-band in the presence of rain.
II. APPROACH
a) Collect SAR measurements of both rain and surface echoes at different viewing angles in the presence of precipitation.
b) Compare SIR-C collected measurements to air- and ground-truth rain data obtained at several in situ measurement sites.
c) Compare the SIR-C/X-SAR data over several 'rainstorms-of-opportunity' with available meteorological data.
d) Process SAR measurements at different resolutions, and extract Doppler, backscatter and polarization information from processed data.
III. ANTICIPATED RESULTS
a) Quantitative evaluation of the rainfall rate, average rainfall velocity, and height of rain cloud.
b) Achievable spatial resolution for rainfall measurement applications using synthetic aperture syntheses.
c) Quantitative measure of the modification in the ocean scattering mechanism as a result of the impinging raindrops, and comparison of such results with theory and previously obtained experimental data.
d) Determination of the polarization signature of the ocean and the signature's variation in the presence of precipitation.
Dr. Fabian Lozano-Garcia Co-Investigators:
Centro de Calidad Ambiantal Antonio Lot National University of Mexico
ITESM Daniel Pineiro National University of Mexico
Sucursal de Correos "J"
64849 Monterrey, N. L., Mexico
Analysis of Optical and Microwave Data to Assess Dynamics of Mexican Tropical Rain Forest
I. OBJECTIVES
The major objective of this research are to analyze the effect of structural differences and successional stages of the tropical forest, on multispectral, multipolarized and multiple incidence angle data.
II. APPROACH
a) Monitor deforestation processes in tropical regions, in terms of the actual distribution and the dynamics of deforestation. This requires assessing the temporal variations of the forest.
b) Monitoring phenological variation during the annual cycle, as well as long-term analysis. This can only be accomplished by establishing data bases that provide accurate information in a timely manner.
III. ANTICIPATED RESULTS
This research will provide basic information about the relationship between forest parameters and spectral response, radar return, and signal polarization. This project will also derive methodologies that will enable the estimation of tropical deforestation and distinguish the primary forest from the different successional stages.
Dr. John F. McCauley Co-Investigators:
Northern Arizona University Carol S. Breed US Geologic Survey
189 Wilson Canyon Road Hugues Faure University of Marseilles
Sedona, AZ 86336 Bahay Issawi Cairo
Ted A. Maxwell National Air & Space Museum
The Exploration and Reconstruction of the Middle to Late Cenozoic Drainages of the Sahara by Means of the SIR-C Mapping
I. OBJECTIVES
a) Use SIR-C/X-SAR data in a synoptic mode with other remotely sensed data, field, and cartographic data to map relic Cenozoic drainage systems across the Sahara from the Red Sea Hills, Egypt, to the Chad Basin and Atlantic Ocean.
b) Demonstrate applicability of SIR data, used with Landsat, SPOT and high-altitude photographic data, as a new, cost-effective remote geophysical tool for exploration geology.
c) Produce a major report on the distribution of paleodrainages in the Sahara, their relations to the basic tectonic elements of North Africa (basins and swells), and their economic potential.
II. APPROACH
a) Obtain ancillary data including local maps, seismic and drill hole logs, and reports of local researchers, with help of Egyptian and French co-investigators.
b) Use SIR-C/X-SAR along with Landsat, SPOT, and other data to map Tertiary stream courses in areas obscured by windblown sand along gaps between identified paleodrainage segments. Apply results of SIR-A/B image data analyses for well-documented sites in Egypt and Sudan to the interpretation of SIR-C/X-SAR radar images along putative courses of paleodrainages. Analysis of headcut patterns in the Mesozoic and older rocks of this region are the key to this work.
c) Conduct field investigations at critical sites where Cenozoic fluvial deposits (e.g., old stream sand and gravels) are known or are likely to occur. (Outside support from local and US. agencies in African countries will be solicited for detailed subsurface exploration work.)
d) Assess SIR-C signal behavior as it affects our subsurface mapping capability. Fully utilize SIR-C/X-SAR regioal mapping capability.
III. ANTICIPATED RESULTS
a) Major contribution to the knowledge of erosional events from middle to late Tertiary time, which gave rise to the Quaternary geomorphology of North Africa. Hot humid conditions prevailed during most of the Tertiary, whereas progressive desiccation set in during the Quaternary. The effects of this major climatic shift were to preserve the evidence for earlier geologic events beneath a veneer of windblown sand. SIR-C/X-SAR's ability to see through these dry sands makes our proposed work feasible.
b) A major report will be prepared with accompanying maps that we hope will have broad scientific and economic applications (for both the public and private sectors). Prior work in this region has been limited in scope and uneven in quality because of the regions heritage of political fragmentation. SIR-C/X-SAR provides an opportunity for a multi-national effort of regional synthesis for the Saudi Arabian Peninsula.
Dr. John N. Melack Co-Investigators:
Department of Biological Sciences Frank Davis Univ. of Calif., Santa Barbara
University of California Judith Meyer University of Georgia
Santa Barbara, CA 93106
Determining the Extent of Inundation on Subtropical and Tropical River Floodplains Beneath Vegetation of Varying Types and Densities
I. OBJECTIVES
a) Develop a procedure for recovering the presence, absence, and patchy presence of water and its spatial distribution beneath different flood plain plant communities of varying crown closures, densities, stand geometries, and canopy states for sites in Georgia. Test the applicability of the procedure to the Amazon and Alligator river floodplains in Brazil and Australia.
b) Modify, extend, and verify the Santa Barbara radar model for different floodplain vegetation types and densities.
c) Test both discrimination procedures and model predictions for leaf-on/leaf-off and water-on/water-off states against SIR-C/X-SAR and aircraft radar images.
d) Couple the above modeling and discrimination procedures for floodwater detection and delineation for input to conceptual flood stage/flood area hydrologic models.
II. APPROACH
a) Simulate returns with and without water, and under different vegetation types, states (with or without leaves), and densities and compare the results so obtained with both aircraft multipolarization/multifrequency radar and SIR-C/X-SAR images in the three study sites in Georgia.
b) Discriminate between vegetation types and density variations within those types, in the presence and absence of standing water.
c) Exploit the multitemporal capability of SIR-C/X-SAR to isolate the effect of standing water under the forest canopy from the effect of vegetation by comparing imagery of the same wetland stands at high, low, and zero water stages, and leaf-on/leaf-off status.
d) Determine detectability threshold of discontinuous floodplain inundation. Determine the effect of canopy variables on the canopy/standing water interaction by interstand comparisons of wetland sites with different stand structures but under identical flooding conditions, i.e., a continuous sheet of standing water. Determine unique multiparameter calibrated radar signatures for the range of combinations of stand structure and percent water cover.
e) Assess the accuracies achievable with various frequency/polarization/angle combinations for determining water cover.
III. ANTICIPATED RESULTS
a) Assist in the process of overarching theory development.
b) Greatly improve the monitoring of wetland hydrological regimes during the EOS era. Provide a quantitative assessment of the accuracies of radar floodwater mapping beneath vegetation canopies.
Mr. Frank M. Monaldo Co-Investigators:
Johns Hopkins University David Tilley Applied Physics Laboratory
Applied Physics Laboratory David Lyzenga Environ. Res. Inst. of Michigan
Johns Hopkins Road
Laurel, MD 20707-6099
Optimization of SAR Parameters for Ocean Wave Spectra
I. OBJECTIVES
a) Determine the relative contributions from proposed mechanisms for the imaging of ocean surface waves by SARs. These mechanisms include tilt modulation, hydrodynamic modulation, velocity bunching modulation, and the modulations caused by specular and wedge scattering.
b) Establish the dependence upon geometry, radar frequency, ocean wave height, and wind speed and direction of the loss of azimuth resolution associated with SAR wave imaging.
c) Select a set of SAR parameters (geometry, frequency, polarization) that maximizes the fidelity of SAR derived, two-dimensional ocean wave spectra in the context of azimuth resolution limits.
II. APPROACH
a) Strategies for obtaining multi-parameter SAR imagery:
1. Acquire all imagery at multi-frequency and multi-polarization.
2. Acquire imagery in the vicinity of the cross-overs from series of orbits.
3. Acquire imagery at different look angles over several days.
b) Process imagery to produce wave spectra using baseline procedures developed for SIR-B, L-band (HH) data.
III. ANTICIPATED RESULTS
a) Determination of a composite SAR wave imaging model including the effects of all relevant imaging mechanisms.
b) Determination of whether azimuth resolution degradation is alleviated at higher radar frequencies than L-band.
c) Recommendations for SAR geometry, frequency, and polarization to maximize the fidelity of SAR derived wave spectra and alleviate the loss of azimuth resolution associated with high sea states.
Mr. Donald R. Montgomery Co-Investigators:
Office of the Oceanographer of the Navy Charles Luther Office of Naval Research
US. Naval Observatory O. H. Shemdin Ocean Res. and Engineering
Washington, D.C. 20392 D. Sheres University S. Mississippi
G. Valenzuela Naval Research Lab.
S. Mango Naval Research Lab.
U. S. Navy Investigations
I. OBJECTIVES
a) As part of the SIR-C/X-SAR experiment, the US. Navy intends to conduct several scientific remote sensing investigations through extensive synthetic aperture radar (SAR) measurements and observations of the marine environment. These investigations include:
Current Boundary Imaging with SAR - This investigation will evaluate the detectability of current boundaries using SAR images of the Gulf Stream and in the Gulf of Mexico.
Ocean SAR Imaging in the Gulf of Alaska - This investigation will evaluate the detectability of ship wakes and determine under which conditions wakes are or are not visible. Validate existing theories of the sea surface spectral response at high wave numbers and SAR imaging in high sea states.
b) These measurements will support a continuing program of basic research and advanced development directed toward applying satellite technology to military problems, especially Naval applications, and the use of SAR as a potential tool in support of oceanographic research.
II. APPROACH
a) Obtain ground truth measurements in the vicinity of Cape Hatteras near the western boundary of the Gulf Stream and in the Gulf of Mexico.
III. ANTICIPATED RESULTS
These investigations will employ a variety of technical approaches, combining SIR-C/X-SAR data with intensive, fine-scale in situ measurements and aircraft-derived data and will contribute to:
a) New and/or improved models describing the mechanisms involved in SAR imaging of ocean features and improved definition of the limits of applicability of SAR in a maritime environment.
b) An improved understanding of how current boundaries are imaged with SAR and of the detectability criteria for current boundaries.
c) Advances in the understanding of major physical mechanisms driving the generation, propagation, and dissipation of ocean phenomena, such as swell, internal waves, and near surface fine-scale features.
d) Compilation of SAR images and ship wake characteristics correlated with radar, ship, and meteorological parameters.
e) Improved understanding of the mechanisms responsible for SAR imaging of wake characteristics at L, C, and X-band radar frequencies in different sea states, and evaluation of SAR's potential use in synoptic detection/observation/monitoring.
Dr. Richard K. Moore Co-Investigator:
The University of Kansas Julian C. Holtzman University of Kansas
Center for Research, Inc.
2291 Irving Hill Drive-Campus West
Lawrence, KS 66045
Inflight Antenna Pattern Measurement for SIR-C
I. OBJECTIVES
a) Obtain the vertical antenna patterns of the SIR-C radars to allow improved radiometric calibration of data for other investigators.
b) To determine how much the vertical antenna pattern changes after launch to aid in designing future space radars and to determine if such measurements are needed on all future space radars.
II. APPROACH
a) Measure backscatter from areas that are uniform in the large scale, particularly the Amazon basin.
b) Use this backscatter averaged over strips about one km by tens of km to determine the variation of scattered signal with angle away from the beam center.
c) Convert these averages into antenna patterns.
d) Provide patterns to JPL for use in improving radiometric corrections of images for other investigators.
III. ANTICIPATED RESULTS
a) Antenna patterns that are better than those produced preflight.
b) A measure of the change in antenna pattern between ground and space conditions.
Dr. Peter J. Mouginis-Mark Co-Investigators:
Planetary Geosciences Div. V. H. Kaupp University of Arkansas
University of Hawaii H. C. MacDonald University of Arkansas
2525 Correa Road W. P. Waite University of Arkansas
Honolulu, HI 96822
The Eruptive Styles of Basaltic Shield Volcanoes from Shuttle Imaging Radar-C (SIR-C) and X-SAR Data
I. OBJECTIVES
a) To provide a comprehensive understanding of the distribution of volcanic materials on classic examples of basaltic shield volcanoes in Hawaii, Reunion Island (Indian Ocean) and Galapagos (Eastern Pacific).
b) Interpret the preserved eruptive history of each volcano, draw contrasts between each test site in terms of the role of the tectonic setting on basaltic volcanism, and make inferences about the internal structure of the volcano and its magma chamber.
II. APPROACH
a) Develop criteria for the discrimination of volcanic materials (lava flow types and ash deposits) using multi-parameter SIR-C/X-SAR data. Determine the optimum frequencies, polarizations and incidence angles from the first SIR-C/X-SAR mission, and obtain data for each volcano during the second mission in mapping-mode with fixed radar parameters. Aircraft SAR data from NASA's DC-8 will be used to help develop these optimum radar parameters, as will field measurements of local topography and dielectric constant.
b) Investigate the complete radar scattering matrix for the volcanic surfaces, using the phase information contained within the quad-pol SIR-C data. The radar data will be used to map the distribution of volcanic materials, and these maps will then be interpreted by both photogeologic and field methods to assess the style(s) of emplacement of lava flows and ash deposits at each test site.
III. ANTICIPATED RESULTS
a) If Kilauea volcano is still active during the mission, we expect to test the first near real-time tracking of an active lava flow using radar. Radar scattering work in Hawaii will allow us to quantify the types of lavas seen on other terrestrial volcanoes, thereby permitting an assessment of the eruption rate of magma on some less well studied volcanoes.
b) Work in the Galapagos will permit details of the structure and eruptive history of the seven active volcanoes to be interpreted and compared to active volcanoes in Hawaii and the Reunion Islands. Maps of lava flows, craters, fissures, etc. of the volcanoes in Kamchatka will greatly improve our knowledge of these poorly known volcanoes.
c) Compare the roles of tectonic setting and spatial variations in activity in a way that has not been possible before using a uniform data set for physically separated landforms.
d) To obtain this regional view, we will develop radar scattering models that enable us to take local test data and extrapolate these observations to the regional scale. Such methods are deemed to be particularly important as the geologic community prepares itself not only to study geographically-isolated terrestrial landforms using ERS-1, JERS-1, and EOS data sets, but also in the analysis of planetary volcanic terrains such as those investigated on Venus by NASA's Magellan spacecraft.
Dr. Pasquale Murino Co-Investigators:
Istituto U. Nobile J. Nithack DLR Oberpfaffenhofen
Piazzale V. Tecchio, 80 K. Krishnanunni Indian Space Res. Organization
80125 Napoli, ITALY F. Jaskolla University of Munchen
Geology of the Campanian Test Site
I. OBJECTIVES
The proposed experiments will evaluate the capabilities of multiple parameter spaceborne SAR in geological, agricultural, and oceanological applications at the Campanian Test Site (Southern Italy).
II. APPROACH
The proposed research aims at a large scale and multidisciplinary study of the whole region, using the specific acquaintances and synergistic studies of the researchers working in diverse scientific disciplines. A global geological, hydrogeological, agricultural, marine and coastal area study using SAR data and optical imagery is planned.
III. ANTICIPATED RESULTS
It is expected that by using L, C, and X band imagery, all the necessary information on the geometry of the area will be obtained. The aim of the research is a regional reconstruction of the structural and volcano tectonics setting and its correlation with plate-tectonics and earthquake epicenter. This will permit the drawing of updated structural and hydrogeological maps.
Dr. Jack F. Paris Co-Investigator:
Department of Geography Walter E. Westman Univ. of California, Berkeley
California State University
Fresno, CA 93740-0069
Global Biodiversity: Assessment of Habitat Change and Species Extinctions with Multiparameter Synthetic Aperture Radar (SAR) Data
I. OBJECTIVES
a) Study the impact of tropical forest fragmentation on local populations of endangered and threatened species of certain mammals, butterflies, birds, and plants. Vegetation information from SIR-C/X-SAR data over three tropical-forest intensive-study sites will aid an independent, broader study of forest fragmentation and its effects on biodiversity.
b) Add the unique, detailed information on forest fragmentation from spacecraft-based SAR to the broader study begun in 1988.
c) Use imaging data from the Landsat Multispectral Scanner (MSS) and the National Oceanographic and Atmospheric Agency (NOAA) Advanced Very-High Resolution Radiometer (AVHRR) to assess on a biome scale, but with less spatial resolution than that of the SIR-C/X-SAR data.
d) Evaluate the use of the unique information about forest distributions and stand conditions expected from multiparameter synthetic aperture radar (SAR) relative to that from the MSS and AVHRR.
II. APPROACH
a) Species diversity and population dynamics are affected by the size, degree of isolation, and condition of forest habitats.(e.g., due to cultural deforestation or natural disturbances such as fire). The broader project will predict the changes in endangerment status of mammals, birds, butterflies, and certain plant groups in the subject tropical areas. To assess the impact of remotely-sensed forest changes, the investigators in the broader study will use a combination of ecological simulation modeling, biogeographic theory, a global georeferenced database of species occurrence, abundance, and habitat preferences, and field data on the response of subject species to habitat fragmentation.
b) While much information is expected from the independent study through the use of data from the MSS and AVHRR, SIR-C/X-SAR data will provide unique information about forest conditions. A biome-wide study using SAR could not be done with the limited SIR-C/X-SAR data (taken over two one-week periods); this broader application of SAR data, if proven feasible in the SIR-C/X-SAR project, would have to await EOS SAR or other long-term radar systems to be in Earth orbit in the 1990's and beyond.
1. Specifically, data from the multiparameter SIR-C SAR [especially from L-band multipolarization channels] will be useful in distinguishing between closed forest (100% canopy closure), woodland (50-99% canopy closure), open woodland (10-49% canopy closure), shrub land, and grassland. Furthermore, we expect quantitative information on early forest regrowth.
2. Recent results (Ulaby, et al., 1986) from studies of textural information in a block of SAR pixels suggests that forests of different types and stages of maturity may have qualitative differences in textural properties useful for forest-habitat characterization. Differentiation of successional stages of recovery in the tropics will add to model precision, both for the biodiversity project and for other research goals. Also, if standing water exists beneath forests, L-band SAR data often responds (presents a brighter image) in a way that such areas can be delineated.
III. ANTICIPATED RESULTS
a) Provide valuable, relatively high spatial resolution information about forest fragmentation conditions for use in refining such estimates based on MSS and AVHRR data.
b) Provide valuable insight into the extended and broader area usage of spacecraft SAR data (e.g., from the EOS SAR) for studies of tropical forest type classification, biodiversity, and species loss in future years (i.e., during the EOS era).
c) Promote the use of remotely-sensed data for the study of an important ecological issue -- the impact of cultural activities on forest habitats and on the threatened and endangered species that reside in these.
Dr. Kyaw Tha Paw U Co-Investigators:
Department of Land, Air & Water Resources Roger Shaw Univ. of California, Davis
Univ. of California, Davis Susan Ustin Univ. of California, Davis
Davis, CA 95616
Turbulent Exchange at Vegetated Surfaces and Evaluation of Estimates of Canopy Structure Using SIR-C Data
I. OBJECTIVES
a) To characterize the turbulent exchanges of momentum, heat and gases from plant surfaces.
b) To evaluate the effects of foliage density, structure and height on the exchanges.
c) To evaluate the use of SIR-C/X-SAR remotely sensed data for estimating information regarding the type, structure, and status of vegetation needed for estimating the exchanges of momentum, heat and gases.
II. APPROACH
a) Field experiments will examine the nature of turbulent structures which transport carbon dioxide, water vapor, heat, and momentum. The effects of the canopy structure on turbulence will be determined.
1. Fast-response sonic and infrared sensors will provide turbulence and flux data. These data will be used to identify coherent structures and establish relationships between turbulent flow statistics.
2. A higher-order closure model describing the soil-plant atmosphere continuum will be used to interpret the data.
b) We will determine the feasibility of using SIR-C/X-SAR data for measuring the canopy structure in field experiments coupled with (a).
1. SIR-C/X-SAR data will be corrected. Microwave and TM (or other optical data) will be used to produce a canopy structure map.
2. The utility of SIR-C/X-SAR, ground-based microwave, and aircraft-based SAR data will be evaluated using conventional measures of canopy structure.
III. ANTICIPATED RESULTS
a) The fluxes of gases, momentum, and heat from vegetated surfaces will be estimated with greater accuracy using the results of the micrometeorological experiments.
b) The effects of canopy structure and roughness on turbulence and fluxes will be established.
c) Limitations of using microwave data to measure plant structure will be identified. Recommendations for future instrument usage and design will be made.
Dr. Kevin O. Pope Co-Investigators:
Geo Eco Arc Research Lorrain Giddings Goddard Space Flight Center
La Cañada, CA Jack F. Paris California State Univ., Fresno
Byron L. Wood NASA, Ames
Radar Investigations of Wetland Hydrology in the Seasonal Tropics
I. OBJECTIVES
a) Develop a model of multiparameter radar backscatter from wetland vegetation and substrates.
b) Characterize seasonal hydrological changes in tropical wetland ecosystems on a regional scale with multitemporal and multiparameter radar data.
c) Determine the relationships between hydrological regime and species composition, physiognomy, phenology, and biomass of tropical wetlands.
d) Gather information important to mitigating human impact on tropical wetlands and future reduction of vector-borne disease.
II. APPROACH
a) Adapt existing models of microwave scattering and absorption to the study of wetland ecosystems.
b) Select a test site based on scientific objectives, existing data, and foreign collaborators, deployment constraints of DC-8 SAR, and coordination with other SlR-C/X-SAR investigators.
c) Acquire vegetation, hydrology, DC-8 SAR, SIR-C/X-SAR, and space and airborne multispectral optical data of test site covering an annual cycle (two DC-8 and two SIR-C/X-SAR missions).
d) Verify backscatter model with field, optical, and SAR data.
e) Determine seasonal changes in wetland hydrology and vegetation and their relationship to one another.
III. ANTICIPATED RESULTS
a) Use our backscatter model, field and optical data to isolate unique SAR backscatter signatures for changes in wetland inundation and soil moisture.
b) Construct four thematic maps of the test site depicting seasonal changes in wetland hydrology and vegetation.
c) Demonstrate correlations between hydrologic regime and wetland vegetation and infer causal relationships.
d) Establish a basis for future multitemporal multisensor studies of wetlands with the Earth Observing System (EOS).
Dr. Keith Raney Co-Investigator:
RADARSAT C. S. Nilsson CSIRO-Marine Lab., Aust.
110 O'Connor Street, Suite 200
Ottawa, Ontario K1P OY7
CANADA
Synthetic Aperture Radar Ocean Imaging Physics
I. OBJECTIVES
a) Gain a better understanding of SAR ocean surface imaging physics by comparing SIR-C/X-SAR data, coincident airborne SAR under flights, perhaps coincident ERS-1 SAR data, and in situ directional wave spectrum measurements and ocean observations.
b) Study surface gravity waves, internal waves, mesoscale features, wind signatures, and ship detection.
II. APPROACH
a) Four study sites will be selected. The first site corresponds to a nominally winter SIR-C/X-SAR flight, and is centered upon the edge of the marginal ice zone off the coast of Newfoundland in the Atlantic Ocean. The second site corresponds to a nominally summer SIR-C/X-SAR flight, and is off the West coast of Vancouver Island near the entrance of Juan de Fuca Strait in the Pacific Ocean. The third site is in the Tasman Sea and the fourth site is the East Australia Current. These four study sites will present a variety of ocean features and conditions for study in a multi-sensor experiment.
b) The ocean wave analysis will center around conversion of SAR imagery into reliable directional wave height spectra. Particular emphasis will be placed upon inter-sensor comparisons, and the inclusion of optimal SAR processing schemes such as adaptive multi-look processing and the explicit inclusion of noncoherent scene motion effects.
c) Mesoscale ocean features will be tracked via AVHRR imagery and subsequently searched for in the resulting SAR imagery. Internal gravity wave signatures will be analyzed for wavelength and corresponding propagation velocities will be compared with those predicted by in situ CTD surveys. Wind signatures will be searched for in the data and correlated with the winds predicted by surface pressure maps. Ship detection exercises will be based upon observations of the research vessels present in the study site, and any chance observations of icebergs in the winter study site.
III. ANTICIPATED RESULTS
a) Improved understanding of the SAR imaging of ocean surface waves, particularly the dependence of aspects of the SAR geometry, operating configurations, and SAR processing upon the image fidelity of surface gravity waves with an azimuthal wavenumber component.
b) Optimal SAR geometries and processing schemes for the observation of internal waves, mesoscale features, wind signatures, and hard targets in sea clutter will be established.
Dr. K. Jon Ranson Co-Investigators:
Biospheric Sciences Branch-Code 923 Guoqing Sun Science Systems Applic., Inc.
Goddard Space Flight Center Herman H. Shugart University of Virginia
Greenbelt, MD 20771 James A. Smith Goddard Space Flight Center
Imaging Radar Data Analysis for Forest Ecosystem Modeling
I. OBJECTIVES
The overall objective of this proposed work is to capitalize on and develop the unique advantages of satellite imaging radar data combined with models of forest ecosystem dynamics for characterizing northern/boreal forest ecosystems, especially with regard to the interpretation of landscape patterns and processes at local and regional scales. Specific objectives are:
a) Use radar observations to help infer where landscape pattern and process ecosystem models succeed or fail at regional spatial scales and inter-annual temporal scales.
b) Use radar data to check potentially observable forest ecosystem model predicted attributes.
c) Use radar observations and models to extract biophysical properties of forest canopies, soils and hydrologic parameters used in our forest ecosystem models.
II. APPROACH
a) Use standard SAR image processing and analysis techniques (e.g., to first extract radar channels and then map the changes in composition, species and gap size distributions) to characterize ecosystem states over selected and modeled study sites. AIRSAR aircraft missions over our intensive sites will be used to guide our later satellite radar analyses.
b) Analyses of field and aircraft data collected over our study sites will be used to explore quasi-statistical relationships between measured response and ecosystem attributes. These relationships may then be applied to satellite collected data to make more detailed checks on ecosystem model performance.
c) Physically based radar models will be applied to existing and field collected data over subsets of our study sites to examine radar and optical scattering from different scene components, useful for objectives a) and b) above, and to develop model inversion strategies for selected ecosystem model input parameters.
III. ANTICIPATED RESULTS
a) The utility of space-borne SAR for guiding the conditions under which ecosystem model assumptions can be relaxed, or conversely, where new mechanisms must be incorporated into models applied at these relatively unexplored spatial scales will be demonstrated.
b) A further tool for evaluating detailed model processes will be explored especially in the regional spatial domain where more traditional methods are difficult to apply.
c) Extract canopy structural parameters from radar observations which can be applied to optical radiative transfer models important for calculating the internal and external radiation regime, or vice versa.
Dr. Chris G. Rapley Co-Investigators:
University College London Wyn Cudlip University College London
Mullard Space Science Lab Myszka Guzkowska University College London
Holmbury St Mary, Dorking Ian Mason University College London
Surrey, RH5 6NT Jeff Ridley University College London
UNITED KINGDOM
Combined Altimetry and SAR Imagery of a Desert Test Site
I. OBJECTIVES
a) To carry out a technical and geophysical investigation of scanning-beam, beam-limited altimetry using SIR-C/X-SAR at vertical incidence angle over a well-characterized desert site.
b) To evaluate and compare the height information obtainable from SAR-interferometry and SAR-stereo over the selected desert test site.
c) To obtain multi-frequency, multi-polarization, multi-look angle SAR images of the desert test site covering several surface types, to investigate the surface and subsurface features and properties which can be measured, and to define optimum observing parameters.
d) To evaluate the role of satellite remote sensing, and satellite altimetry and SAR in particular, to improving the understanding of the geomorphological processes of erosion, transportation, and deposition in arid regions. To develop and validate analysis techniques with global applicability for the study and monitoring of desert processes, particularly those associated with climate change.
II. APPROACH
a) A test site in the Central Australian desert will be selected using Seasat and Geosat altimetry data, Landsat imagery, aerial photography, and surface reconnaissance. Surface measurements will be made, including Ku-band scatterometry, and the measurement of surface geometry, soil type, grain size, dielectric properties, moisture content, and vegetation cover. A network of control locations will be established to standardize subsequent field measurements. Additional surface measurements will be carried out during overflights.
III. ANTICIPATED RESULTS
a) Demonstration of scanned-beam, beam-limited altimetry and along-track synthetic aperture processing resulting in improved specifications for future instruments. A quantitative assessment of SAR-interferometric and SAR-stereo height estimation.
b) Improved understanding of the radar backscatter mechanism from homogeneous, rough surfaces, particularly at vertical incidence angles. An improved understanding of the information content of SAR imagery of arid regions, and the specification of optimum observing parameters for desert imagery.
c) Develop an improved digital terrain model (DTM) for the desert test site, including topography and surface/subsurface characteristics such as surface roughness, soil type, moisture content, and vegetation cover.
d) The development and validation of techniques and methodologies for the determination and monitoring of desert morphological processes, particularly those related to climate change.
Dr. Helmut Rott Co-Investigators:
Institute for Meteorology and Geophysics M. Buchroithner Research Ctr. Joanneum
University of Innsbruck C. Matzler University of Bern
Inrain 52 O. Reinwarth Bavarian Academy of Sciences
A-6020 Innsbruck, AUSTRIA
High Alpine SAR Experiment
I. OBJECTIVES
a) Carefully surveyed test sites in the Alps are proposed as model sites for applications of multi-parameter SAR in high alpine areas.
b) Using extensive comparative data to gain a better understanding of the SAR response to physical target properties and improve the methods for SAR data analysis. The experiment will emphasize the following topics:
1. Monitoring of glacier properties and seasonal snow cover,
2. Mapping geological and erosional features,
3. Topographic mapping from radar stereo imagery, and
4. Mapping alpine vegetation and sub-alpine forests.
II. APPROACH
a) The physical properties and the back scattering signatures of the main targets will be measured on the ground and compared with the multi-parameter SAR signatures.
b) Digital elevation data, detailed thematic maps, and field measurements will be used for data analysis and validation. Airborne imagery and optical satellite imagery will be obtained for comparison and will be used for generating multi-sensor data sets.
c) SAR images will be geometrically rectified and synthetic radar images will be generated as the basis for quantitative analysis of the SAR data.
d) Topographic mapping will be carried out for different SAR stereo-models (SAR channels, look/intersection angles). Methods of direct thematic mapping through on-line stereo-restitution will be tested.
III. ANTICIPATED RESULTS
a) Improved understanding of spaceborne SAR's ability to detect physical properties of the seasonal snow cover, of glaciers, and for deriving geological and erosional features.
b) Evaluate the feasibility for extracting information on alpine vegetation and sub-alpine forests from multiparameter SAR data.
c) Improved digital methods for thematic mapping of glaciers, snow cover, geologic structures and erosional features. Improved methods for high-precision contour and line mapping using radar stereo imagery and the assessment of mapping accuracies.
d) Evaluate the possibility of external radar calibration through backscatter measurements on homogeneous glacier areas.
e) Determine the optimum SAR parameters for future advanced earth observation systems regarding operational tasks in alpine terrain.
Dr. Gerald G. Schaber Co-Investigators:
US. Geological Survey Carol Breed US Geologic Survey
2255 North Gemini Drive Philip Davis US Geologic Survey
Flagstaff, AZ 86001 Hany A. Hamroush Cairo University
Bahay Issawi Cairo
Nicholas Lancaster Arizona State University
John McCauley Northern Arizona University
Michael N. Machette US Geologic Survey
Gary Olhoeft US Geologic Survey James T. Teller University of Manitoba
Justin M. Wilkinson University of Chicago
SIR-C Surface and Subsurface Responses from Documented Test Site Localities in the Sahara, Namib, and Kalahari Deserts, Africa and the Jornada del Muerto, New Mexico
I. OBJECTIVES
a) To determine the optimum SIR sensor configuration for detection of desert duricrust and to use this understanding to reconstruct the paleoclimatic history of two large desert regions in Africa.
b) To determine the ability of SIR-C/X-SAR (alone and synergistically with other remotely-sensed data) to delineate and map near-surface, regional caliche deposits and other "fossil" duricrusts formed during a series of less arid intervals in Africa, but now obscured by aeolian sand.
c) To test various sensor parameter configurations of SIR-C/X-SAR for discriminating among surface and near-surface stratigraphic units in well documented sites from the SIR-A and SIR-B experiments. The results will be used to calibrate the penetration and backscattering capabilities of the SIR-C/X-SAR.
II. APPROACH
a) Extend laboratory measurements and the SIR-A/B geometric scatter model for calichified sediments in arid, sand-covered terrains to higher frequencies and a wider range of sample physical parameters. Refine and use digital-image-processing procedures developed following SIR-A/B to discriminate and map the distribution of caliche deposits and other surface and subsurface units using coregistered composites of SIR Landsat Thematic Mapper (TM) and SPOT image data.
b) Using well-understood African and United States sites, document and establish limits on SIR-C/X-SAR signal behavior in hyperarid-to-semiarid regions. Specifically, evaluate the effects of surficial/subsurface geologic conditions on SIR-C response in various sensor configurations.
III. ANTICIPATED RESULTS
a) An improved understanding of radar backscatter and penetration in hyperarid-to-semiarid terrains that was initiated during our SIR-A/B investigations. Improved models of geometric scattering effects on SIR signal penetration.
b) Refinement of synergistic remote methods to identify various types and stages of datable, authigenic CaCO3 deposits related to successive changes in climate and surface geologic processes during the Quaternary. Significant new data on the spatial and chronological distribution of semiarid paleoclimatic zones in Africa.
Dr. Joao Vianei Soares Co-Investigators:
Instituto de Pesquisas Espacias H. J. H. Kux University of Freiburg
Ave. Dos Astronauts, 1758
Caixa Postal 515, 12227-010
São José dos Campos
S.P. BRAZIL
Microwave Remote Sensing Data from a Spaceborne Platform as a Tool to Monitor the Hydrological Cycle of a Floodplain Area ("VARZEA") at Northeast Brazil.
I. OBJECTIVES
a) To develop an algorithm to monitor the hydrological cycle over agricultural areas, based on data derived from SAR imagery and meterological data at a floodplain area ("varzea") in Northeast Brazil (Pernambuco State).
b) To evaluate the possibility of discriminating among cultures at the time of the SIR-C/X-SAR overflight To describe and analyze the attenuation properties of the cultures as related to radar parameters including frequency, polarization, and incidence angle.
II. APPROACH
a) Conduct the SIR-C/X-SAR study at the Bebedouro Irrigation Project in northeastern Brazil. This project has been developed to improve and develop new agricultural and cattle raising techniques for the dry sections of Northeast Brazil, and specifically to study problems related to soil hydrology, soil moisture and dryness, evapotranspiration and soil and water salinization resulting from improper irrigation practices.
b) Acquire in situ data during the mission including meteorological data, depth of water at site, and soil sample analyses.
III. ANTICIPATED RESULTS
a) Establishment of a methodology to estimate soil moisture and evaporation rates at a regional scale for irrigation projects, climatological studies, and as an input to numerical models for weather forecasting, based on operational SAR systems such as the Earth Observing System (EOS).
b) Development of a data base relying on a multiparameter SAR system and its interaction with different tropical agricultural crops.
c) Development and acquisition of software for the classification and enhancement of digital SAR images to assist in agricultural and hydrological studies in the future.
Dr. Robert J. Stern Co-Investigators:
Center for Lithospheric Studies Timothy H. Dixon Jet Propulsion Laboratory
University of Texas at Dallas Kent C. Nielson University of Texas at Dallas
Box 688 Mohammed Sultan Washington Univ., St. Louis
Richardson, TX 75083
SIR-C Studies of the Precambrian Hamisana and Nakasib Structures, NE Sudan, in Arid Regions of Low Relief and in the Subsurface
I. OBJECTIVES
a) Develop techniques for optimizing structural analysis of basement trends in arid regions with extremely subdued topography and/or thin aeolian cover.
b) Apply results of a) to map the southern extension of the Hamisana Shear Zone and the western extension of Nakasib Suture.
c) Apply results of b) to constrain the roles of terrane accretion and strike-slip re-organization for late Precambrian crustal evolution in NE Africa.
II. APPROACH
a) Pre- and post-mission field studies will focus on defining the major basement structures of the NE Sudan to determine their deformational history and orientation of structural fabrics.
b) Interface with ongoing LANDSAT TM and field studies of the Hamisana Shear Zone and initiate similar studies for the Nakasib Suture. Ancillary data is also requested (i.e., hand-held photography, large format camera).
c) During the first SIR-C/X-SAR flight, we will determine the best configuration of radar parameters for resolving the structures in the study area. The following will assist in this determination.
1. Dual frequency (L-and C-band or L- and X-band), like polarized (V-V or H-H). Penetration is inversely proportional to frequency, so comparison of L with C- or X-bands should allow discrimination of surface vs. subsurface effects.
2. Single frequency (L-band), dual polarization (V-V or H-H) and (V-H or H-V). This will allow examination of possible polarization effects in subsurface and near-surface features.
3. Incidence angle should be as high as possible, to mimic as much as possible a SEASAT imaging configuration. This will maximize weak returns off the subsurface and will enhance subtle topographic features in this low relief terrain. Some of these may have structural significance due to preferential erosion.
d) Second flight experiment should get coverage over the same area using approaches iv) a) and b), to the extent possible to determine the best configuration for the subsequent experiment.
III. ANTICIPATED RESULTS
a) Better understanding of the southern continuation of the Hamisana Shear Zone and the western continuation of the Nakasib Suture and the sequence of deformational events (collisions, strike slip faulting, etc) that led to the formation of the continental crust of this poorly known region. This will better constrain models linking the major basement structures of NE Africa and those of the Mozambique Belt of East Africa.
b) Better understanding of the imaging techniques necessary for elucidating buried and low-relief structures in arid terrains.
c) Better understanding of the radar signature of suture zones and strike-slip zones of deformation in terrains and climates analogous to those expected on planetary surfaces such as Venus.
Dr. Geoffrey R. Taylor Co-Investigators:
Dept. of Applied Geology E. H. Fooks Univ. of New South Wales
Univ. of New South Wales J. Leach CSIRO
P.O. Box 1 A. K. Milne Univ. of New South Wales
Kensington NSW 2033 J. Acworth Univ. of New South Wales
AUSTRALIA J. Odins Water Res., New South Wales
The Evaluation of SIR-C Imagery for Surficial Sediment Mapping and Groundwater Management in Australia
I. OBJECTIVES
a) To assess the utility of multipolarization multifrequency spaceborne radar for surficial sediment mapping (4.2.5.3. lithology, rock weathering and geochronology, Science Plan) and groundwater management (4.3.5.1, arid regimes, Science Plan) in a variety of Australian environments.
b) To establish the utility of the SIR-C imagery for recognizing basement structures (4.2.5.4, tectonics and geologic boundaries, Science Plan) by mapping drape-related fractures in overlying surficial sediments.
II. APPROACH
a) Sites have been selected across Australia so as to cover a range of sedimentary environments from arid to temperate.
b) Sites at Kerang, Palm Valley, Fowlers Gap, Cooper Creek, Lake Eyre and Condobolin contain Precambrian and Devonian sediment outcrops, Tertiary and Quaternary sediments, and fresh and saltwater lake systems. A large data base of remotely sensed imagery covering these regions is already available.
c) The study will involve image analysis and enhancement. Detailed ground investigations will involve petrology, surface roughness determinations, moisture measurements, dielectric constant determinations, salinity analyses, and signal calibration.
d) Studies will be extended along swath into differing hydrological environments each with particular water-management problems. Sites within the Murray Darling Basin, Cooper Creek/Diamantina Rivers and Simpson Desert will be included.
e) Block faulting in Devonian to Cretaceous age sediments in petroleum bearing sediments in the Cooper and Eromanga Basins is propagated upwards into overlying Tertiary to recent sediment cover. Comparative studies of these drape-related features employing lineament analyses from several remotely sensed data bases and the SIR-C/X-SAR imagery will be carried out at along-swath study sites.
III. ANTICIPATED RESULTS
a) Map surficial deposits of different type and age by surface roughness, sub-surface volume scattering, cross-polarization returns and phase difference images. These maps will have important consequences for the recognition of potential aquifer materials in arid and semi-arid regions.
b) Map seepage zones in areas of internal drainage and saltlake formation using variations in dielectric constant to determine moisture contents and conducting salt layers. These maps will be important to understanding natural salt-lake systems and salinity management in irrigation areas such as the Murray Darling Basin and elsewhere in the world.
c) Demonstrate that spaceborne radar is a powerful tool for mapping basement tectonic features through overlying surficial sediments. While having implications for petroleum exploration, this will also be important for recognizing high permeability zones for the siting of water wells.
d) Test the effect on varying amounts of vegetation cover on our ability to achieve these results.
Dr. Fawwaz T. Ulaby Co-Investigators:
University of Michigan M. Craig Dobson University of Michigan
Radiation Laboratory T. Sharik Michigan Technical University
Department of EECS J. A. Weber University of Michigan
1301 Beal
Ann Arbor, MI 48109-2122
Polarimetric Radar Observations of Forest State for Determination of Ecosystem Process
I. OBJECTIVES
a) The objectives of this research are to test the hypotheses that ecologically significant forest state parameters may be estimated from SAR data. These include estimation of above ground biomass, plant water status, and near surface soil moisture under certain forest conditions.
b) Test hypotheses in the northern hardwoods forest community, refine them if necessary, and establish techniques for retrieving this information from orbital SARs such as SIR-C/X-SAR.
II. APPROACH
a) The study will be conducted in three phases as follows:
1. Monitor the dielectric and geometric properties of selected forest canopies on a diurnal and seasonal basis. Use these values to simulate radar backscatter as a function of frequency, polarization, incidence angle, and range into the canopy as a function of time using the Michigan Microwave Canopy Scattering Model (MIMICS). Simulations will be evaluated on the basis of concurrent multifrequency, polarimetric backscatter observations using AIRSAR.
2. Refine initial hypotheses on the basis of sensitivity studies generated using MIMICS for a range of forest stand conditions existing at the test site area near the University of Michigan Biological Station (UMBS). Studies will use databases established at UMBS over the last 78 years. An airborne SAR program will be conducted prior to SIR-C/X-SAR to test these hypotheses under heterogeneous field conditions and evaluate retrieval techniques derived from inversions of the MIMICS model.
3. Demonstrate the utility and the lateral geographic extendibility of these retrieval techniques beyond the study region using SIR-C/X-SAR data. Issues of sensor calibration are critical to this phase and on-site external calibration techniques will therefore be applied throughout the experimental program.
III. ANTICIPATED RESULTS
a) Determination of the dynamic range of radar backscatter from northern hardwood canopies in response to diurnal, daily, and seasonal dynamics.
b) Validation of a robust forest canopy scattering model (MIMICS) which can then be applied to other forest conditions.
c) Definition of the retrieval techniques and their respective accuracies. Evaluate the limitations for each hypothesis.
Dr. Sergio Vetrella Co-Investigators:
Cattedra di Ingegneria dei D. Solimini University Roma
Sistemi Aerospaziali
Facolta di Ingegneria
Piazzale Tecchio, 80
80125 Napoli, ITALY
Passive and Active Calibrators for Multifrequency and Multiangle X-SAR/SIR-C Image Radiometric and Geometric Corrections
I. OBJECTIVES
a) Prove that despite the considerable number of variables contributing to SIR-C/X-SAR image formation, the data can reveal system descriptors by studying the system response to "known targets" (either point-like or extended) within the scene.
II. APPROACH
a) Design and develop passive and active calibrators that will be used to instrument approximately 15 km2 of the test site. Instruments will be accurately located with respect to the geodetic network.
b) This instrumentation will be accurately calibrated, using an anecoic chamber and an antenna range. Prototypes of the instrumentation will be field-tested during the future airborne SAR campaigns in preparation for the SIR-C/X-SAR missions.
c) The multiangle capability and/or a slight shift between successive orbits will provide images of the test area under different illumination angles.
III. ANTICIPATED RESULTS
a) Development of a step-by-step research program focused on airborne campaigns to design, test, and operate a set of ad-hoc multifrequency instrumentation for SAR calibration and data validation.
b) Integration of the calibration data with raw SAR data for fine tuning of processor parameters.
c) Evaluation of the potential of SAR interferometry for topographic mapping, based on point targets of known radar cross-section (RCS), geographic coordinates, and phase behavior.
d) Improvement of the existing RCS databases.
Dr. Daniel Vidal-Madjar Co-Investigators:
C. N. E. T. Michel Normand CEMAGREF
U. V. S. Q. Didier Massonet CNES/TI
10-12 Avenue de l'Europe
78140 VEC12Y
FRANCE
Test of Roughness and Moisture Algorithms Using Multiparameter Space Borne SAR and Application to Surface Hydrology
I. OBJECTIVES
a) Evaluate the usefulness of radar-derived parameters in surface hydrology.
b) Demonstrate the usefulness of the squint mode in the case of bare soil observations.
c) Compare various roughness/moisture algorithms in a real space imaging mode.
II. APPROACH
a) The proposal is based on comparison between radar observation and well documented ground truth within a watershed.
b) The radar data will be compared to ground data using existing surface/wave interaction models.
c) An airborne dual frequency (C and X) multipolarization scatterometer will be used to calibrate radar data and to complete the data set (in view angle).
III. ANTICIPATED RESULTS
a) Calibration of the Shuttle radars over distributed targets
b) Test of multi-incidence angle algorithms using squint mode SAR
c) Test of roughness/moisture algorithms
d) Evaluation of the usefulness of SAR in surface hydrology including surface runoff parameters, rain discharge relationships, flood forecasting, improvement of hydrological modeling.
Dr. James R. Wang Co-Investigators:
Laboratory for Oceans Edwin T. Engmann USDA/Agr. Res. Center
Code 675 Manfred Owe GSFC
Goddard Space Flight Center James C. Shiue GSFC
Greenbelt, MD 20771
SIR-C Measurements of Soil Moisture, Vegetation and Surface Roughness, and their Hydrological Application
I. OBJECTIVES
a) Analysis of SIR-C/X-SAR response to soil moisture, vegetation and surface roughness and development of an algorithm to retrieve these parameters.
b) Combination of the visible and near-infrared data and the SIR-C/X-SAR data to improve the range and accuracy of vegetation classification.
c) Testing of theoretical models for microwave propagation with SIR-C/X-SAR and microwave radiometric measurements over rough surfaces.
d) Evaluation of a water balance model using SIR-C/X-SAR derived soil moisture values and other ancillary data.
II. APPROACH
a) Selection of a test site which would provide a wide spectrum of soil moisture, vegetation and surface roughness for SIR-C/X-SAR observations.
b) Request of aircraft polarimeter and radiometer flights before and during the SIR-C/X-SAR mission.
c) Activities of the ground truth data collection, as well as other relevant satellite and ancillary data acquisitions.
d) Processing of data from SIR-C/X-SAR, satellite, and aircraft flights. Analysis of microwave signatures with respect to surface parameters leading to algorithm development for parameter retrieval. Evaluation of a generalized water balance model using the retrieved soil moisture and other ancillary data.
III. ANTICIPATED RESULTS
a) The relationship between surface parameters and imaging radar signatures will be established. An algorithm based on this relationship to retrieve the surface parameters will be developed.
b) Verify that an imaging radar system with multiple frequencies and polarizations is an efficient tool for vegetation classification. Assessment will be made of the classification scheme improvement when visible and near-infrared data are included.
c) Using SIR-C/X-SAR and ground measured roughness data, assess the validity of current theoretical models for microwave backscatter from rough surfaces.
d) Using the SIR-C/X-SAR retrieved soil moisture and other ancillary data, verify the validity and limitation of a generalized water balance model.
Dr. Rudolf Winter Co-Investigators:
DLR Prof. Kubbauch Universitat Bonn
German Remote Sensing Data Center S. Mohan Space App. Center
D-82234 Oberpfaffenhofen
GERMANY
Information Extraction from Shuttle Radar Images for Forest Applications
I. OBJECTIVE
a) The experiment will attempt to extract all possible information from shuttle borne radar images (SAR) for areas with forest stands.
b) Use extracted information to evaluate/characterize forest parameters including differentiation between coniferous and deciduous forests, tree stand geometry, seasonal changes. Specific radar-tree interaction schemes including dependence of leaf/needle geometry and alignment to radar backscatter will also be investigated.
II. APPROACH
a) Forested areas to be studied in the experiment will comprise the range from non-forest/deforested areas to bushland areas, reforested areas and finally, small groves to large woodlands.
b) The experiment and the proposed data processing algorithms will utilize mainly the X-band SAR data in one polarization, but will also take advantage of the SIR-C L- and C-band data with different polarization and look-angles.
c) The experiment will use geocoded images to co-register the radar data with other geocoded satellite-borne images including multiband TM data and high resolution SPOT data. The strong dependence of radar data on topographic relief will make the incorporation of digital elevation models (DEM) necessary.
d) To obtain information for forest applications the principal backscatter mechanisms of microwaves with trees, trunks, leaves, and needles must be known. Three main parameters can be identified:
1. Radar parameters: These are wavelength, polarization and incidence angle. The SIR-C/X-SAR mission will vary all parameters, delivering a maximum flexibility to the investigators.
2. Target parameters: These can be further sub-divided in geometric parameters such as roughness, density, pattern, height, and dielectric property parameters which are mainly influenced by the moisture content of the canopy. Especially the tree/forest geometry could allow a classification of different species from SAR images.
3. Underlying soil parameters: Mainly the surface roughness and the dielectric properties of the soil which are governed by humidity.
III. ANTICIPATED RESULTS
a) Differentiation of forested and non-forested areas with an assessment of the accuracy of separation.
b) Information on the tree stand geometry, age classes of trees, and seasonal changes.
Dr. Charles A Wood Co-Investigators:
University of North Dakota Anthony England Johnson Space Center
Fargo, ND Minard Hall Escuela Pol. Nacl., Ecuador
Stanley Williams Arizona State University
SIR-C Radar Investigations of Volcanism and Tectonism in the Northern Andes
I. OBJECTIVE
a) Increase understanding of the volcano-tectonic history of the Northern Andes of Colombia and Ecuador by testing and extending the volcano-tectonic segmentation model proposed by Hall and Wood (1985).
b) Develop radar models for detecting and mapping pyroclastic and mudflow deposits at Ruiz and other dangerous volcanoes of the Northern Andes.
II. APPROACH
a) Use SIR-C/X-SAR images to examine areas identified by Hall and Wood as having anomalous volcano-tectonic characteristics; e.g., determine if young volcanoes uncertainly glimpsed in Landsat images of south-central Colombia exist; search for caldera (?) source of extensive, young ashflows in southern Ecuador; map tectonic details of surface area above apparent collision of adjacent subducted slabs.
b) For forested volcanic areas, develop statistical characterizations of terrain morphologies (canopy morphologies) to recognize and classify volcaniclastic terranes of various ages. For vegetation-free areas, develop theoretical scattering models based on the statistical roughness characteristics of volcaniclastic terranes of different ages. These models will be tested against the multi-wavelength, quad-polarized radar signatures of the volcanic terranes at Ruiz volcano (eruptions in 1986, 1945, 1595), Doña Juana (1897), Guagua Pichincha (1660), Cotopaxi (1877), and Tungurahua (1916).
III. ANTICIPATED RESULTS
a) Greatly improve geologic knowledge of poorly mapped, frequently cloud-covered, volcanically active arc.
b) Discover currently unknown source structure for large, 14,000 year old ashflow deposit in southern Ecuador.
c) Increase understanding of a seismically unusal subduction setting.
d) Develop an optimal interpretation of radar data for detection and mapping of pyroclastic/lahar deposits in tropical environments.
e) Improve understanding of distribution and character of poorly mapped deposits at Ruiz and other explosive volcanoes in the area.
f) Recognize prehistoric Ruiz-like deposits around other North Andean volcanoes and hence increase awareness of volcanic hazards.
Dr. Howard A. Zebker Co-Investigators:
Mail Stop 300-235 Charles Elachi Jet Propulsion Laboratory
Jet Propulsion Laboratory Philip Hartl University of Stuttgart
4800 Oak Grove Drive Jakob van Zyl Jet Propulsion Laboratory
Pasadena, CA 91109
Multifrequency Imaging Radar Polarimetry: Geophysical Factors from Penetration Phenomena
I. OBJECTIVES
a) To model, experimental]y characterize, and verify penetration phenomena in hyperarid and vegetated regions using the SIR-C/X-SAR multiparameter radar system and groundbased receivers.
b) To invert measured radar backscatter as a function of frequency and polarization in terms of geophysical parameters of the surface, subsurface and vegetation canopy such as surface roughness, subsurface geomorphology, or tree height and density.
c) To display subsurface and within-canopy features in an image format, thus easing the interpretability of the results.
II. APPROACH
The approach we propose is utilization of multifrequency polarimetry to separate and characterize the radar return into surface and volume scattering components. Specifically, we will:
a) Model the backscatter from hyperarid and vegetated areas in terms of the geophysical parameters describing in particular subsurface and within-canopy structure and composition.
b) Collect SIR-C and supporting aircraft multifrequency polarimetric data.
c) Separate the measured return into surface and subsurface or within-canopy parts based on polarimetric behavior as a function of frequency.
d) Deploy ground receivers during the experiment to measure field strengths at both vertical and horizontal polarizations. These in situ measurements will constrain and confirm our theoretical models.
e) Invert the measured scattering characteristics in terms of the modeled geophysical parameters.
III. ANTICIPATED RESULTS
a) An increased understanding of penetration phenomena in scattering.
b) Identification of sources for backscatter in hyperarid subsurface imaging, and quantitative assessment of the relative contribution of canopy top, volume, and ground surface scattering components to the return signal from vegetation canopies.
c) Solutions for descriptive geophysical parameters in the supersites studied. These results would be of great use to any investigators interpreting images acquired over similar targets by SIR-C or any other radar system.