BOREAS RSS-16 Level-3b DC-8 AIRSAR CM Images Summary The BOREAS RSS-16 team used satellite and aircraft SAR data in conjunction with various ground measurements to determine the moisture regime of the boreal forest. RSS-16 assisted with the acquisition and ordering of NASA JPL AIRSAR data collected from the NASA DC-8 aircraft. The NASA JPL AIRSAR is a side- looking imaging radar system that utilizes the SAR principle to obtain high- resolution images that represent the radar backscatter of the imaged surface at different frequencies and polarizations. The information contained in each pixel of the AIRSAR data represents the radar backscatter for all possible combinations of horizontal and vertical transmit and receive polarizations (i.e., HH, HV, VH, and VV). Geographically, the data cover portions of the BOREAS SSA and NSA. Temporally, the data were acquired from 12-Aug-1993 to 31- Jul-1995. The level-3b AIRSAR CM data are in compressed Stokes matrix format, which has 10 bytes per pixel. From this data format, it is possible to synthesize a number of different radar backscatter measurements. The data are stored in binary image format files. Please note: In early 1998 a problem was found in the AIRSAR Integrated Processor Versions 5.01 and 5.02. This problem affected the backscatter cross section ?? values in some of the BOREAS products. The data that BORIS has archived does not reflect the changes made in the processor software to correct the problem. The corrected data has been delivered to ORNL and will be made available. None of the AIRSAR imagery is contained on the BOREAS CD-ROM series, although an inventory listing of the data collected is included. Table of Contents * 1 Data Set Overview * 2 Investigator(s) * 3 Theory of Measurements * 4 Equipment * 5 Data Acquisition Methods * 6 Observations * 7 Data Description * 8 Data Organization * 9 Data Manipulations * 10 Errors * 11 Notes * 12 Application of the Data Set * 13 Future Modifications and Plans * 14 Software * 15 Data Access * 16 Output Products and Availability * 17 References * 18 Glossary of Terms * 19 List of Acronyms * 20 Document Information 1. Data Set Overview 1.1 Data Set Identification BOREAS RSS-16 Level-3b DC-8 AIRSAR CM Images 1.2 Data Set Introduction The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition of the relevant aircraft image data. Data from the Airborne Synthetic Aperture Radar (AIRSAR) system onboard the National Aeronautics and Space Administration (NASA) DC-8 aircraft were acquired by staff at the Jet Propulsion Laboratory (JPL) and provided for use by BOREAS researchers. 1.3 Objective/Purpose The purpose of this data set is to provide multifrequency and multipolarization Synthetic Aperature Radar (SAR) images over the BOREAS Southern Study Area (SSA). This data set supplements other visible and near-infrared remote sensing images compiled by BOREAS. The level-3b AIRSAR data were acquired at three frequencies of P-band, L-band, and C-band and for all linear polarization combinations (HH, HV, VH, and VV). The level-3b AIRSAR CM image data products contain data from all 12 frequency and polarization combinations. AIRSAR images are used to estimate surface parameters such as canopy water content, soil moisture, and stand biomass and density. 1.4 Summary of Parameters SAR parameters: incidence angle, aircraft altitude, range resolution, azimuth resolution, frequency, polarization. 1.5 Discussion AIRSAR image data gathering for BOREAS was conducted in 1993 and 1994 over the two study areas in Canada. BOREAS was designed to study regional land surface climatology and to develop methods for deriving quantitative information about surface variables from remote sensing data. The AIRSAR experiment was devised to provide surface moisture and vegetation variables suitable for the soil- vegetation-atmosphere interaction models. In particular, the high-resolution data obtained by the AIRSAR system can be used to derive information about the variability of the surface parameters, which in turn can be used to address the scaling problem. 1.6 Related Data Sets BOREAS RSS-16 Level-3b DC-8 AIRSAR SY Images 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Sasan S. Saatchi 2.2 Title of Investigation Estimation of Evapotranspiration Using SAR Derived Parameters 2.3 Contact Information Contact 1 ------------- Dr. Sasan S. Saatchi Jet Propulsion Laboratory Pasadena, CA (818) 354-1051 saatchi@bacchus.jpl.nasa.gov Contact 2 ---------------- Dr. Jakob J. vanZyl Jet Propulsion Laboratory Pasadena, CA (818) 354-1365 Contact 3 ------------- Jeffrey Newcomer Raytheon STX Corporation NASA GSFC Greenbelt, Maryland (301) 286-7858 (301) 286-0239 (fax) Jeffrey.Newcomer@gsfc.nasa.gov 3. Theory of Measurements The basic quantity measured by a polarimetric radar is a complex (amplitude and phase) scattering matrix for each resolution element of the radar image. This implies that AIRSAR is a multichannel system designed to maintain phase coherence between radar antennas and different channels. The polarization states used in the AIRSAR system are based on horizontal and vertical antennas. The radar is configured to measure all possible combinations available from the horizontal (H) and vertical (V) antennas (i.e., H transmitting, H receiving, and so forth). The complete scattering matrix for a resolution element can then be determined. Knowledge of the scattering matrix permits calculation of the received power for any possible combination. 4. Equipment 4.1 Sensor/Instrument Description SAR refers to a technique used to synthesize a very long antenna by combining signals (echoes) received by the radar as it moves along its flight track. NASA JPL currently maintains and operates the AIRSAR/Topographic SAR (TOPSAR), which flies on the NASA DC-8 aircraft. The AIRSAR system is an airborne SAR that operates simultaneously in a fully polarimetric mode at three frequencies (P-, L-, and C- bands). JPL operates the radar aboard the NASA Ames Research Center DC-8 aircraft. The data collected by the AIRSAR system are processed to polarimetric imagery at JPL and provided to the BOREAS Information System (BORIS) in digital and photographic forms. The AIRSAR system provides several output products, including real-time imagery and the final processed digital products. Two of the most common digital products are the Compressed Matrix (CM) products and the Synoptic (SY) products. The real-time imagery is provided to the investigators for a SAR pass. This is a low-resolution, black-and-white, single-frequency/polarization (typically LHH) image of the entire pass. No digital data of this type are provided. Annotation of the image allows the investigators to select areas for further processing. The information on the data includes run name (name assigned to the data acquisition pass, typically the site name), Greewich Mean Time (GMT) (day of year followed by GMT), A/C Lat-Lon, frame count, and frequency/polarization. The standard AIRSAR CM product consists of a 16-look (20-MHz) or 8-look (40-MHz) "polarization compressed" digital file on tape for each frequency (for input to polarization synthesis software provided by JPL) and a color photo product. The frame product corresponds to about 12 km along-track of imagery by 10-15 km across-track. As part of the standard products, the data sets are calibrated by the ground SAR processor. During the 1993 experiment, only limited data were collected over the BOREAS study areas. In 1994, a large amount of imagery was collected and is summarized in Section 7 below. In 1995, a special collection effort was planned to collect imagery over an area of the SSA that had been burned the previous season. 4.1.1 Collection Environment The AIRSAR system operates within the fuselage of the DC-8 aircraft during flight. The AIRSAR was flown at medium altitudes aboard NASA’s DC-8 aircraft based at NASA’s JPL and provided 11-m slant range resolution at an altitude of 8000 m. 4.1.2 Source/Platform NASA DC-8 Aircraft 4.1.3 Source/Platform Mission Objectives The objective was to acquire multipolarization and multifrequency SAR images over the BOREAS study areas and transect region. 4.1.4 Key Variables Polarization, radar frequency, radar look angle, aircraft altitude, range resolution, azimuth resolution, site lat-long coordinates, aircraft geometry. 4.1.5 Principles of Operation The NASA/JPL AIRSAR is a side-looking imaging radar system that utilizes the SAR principle to obtain high resolution images that represent the radar backscatter of the imaged surface at different frequencies and polarizations. 4.1.6 Sensor/Instrument Measurement Geometry During the BOREAS experiment, the instrument was located in the NASA DC-8 aircraft approximately 7,800 m above ground. The antennas are located on the port side of the aircraft looking at an angle over the site. The nominal pointing angle was 28 degrees, which covered the ground surface from approximately 28 to 72 degrees. All DC-8 AIRSAR CM level-3b images are produced at 6 m in range and 12 m in azimuth resolutions. 4.1.7 Manufacturer of Sensor/Instrument Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109 (818) 354-4321 4.2 Calibration 4.2.1 Specifications In one mode of operation, this system is capable of simultaneously collecting all four polarizations (HH, HV, VH, and VV) for three frequencies: L-band (lambda ~ 24 cm), C-band (lambda ~ 6 cm), and P-band (lambda ~ 68 cm). In another mode of operation, the AIRSAR/TOPSAR system collects all four polarizations (HH, HV, VH, and VV) for two frequencies: L-band (lambda ~ 24 cm), and P-band (lambda ~ 68 cm), while operating as an interferometer at C-band to simultaneously generate topographic height data. AIRSAR/TOPSAR also has an along-track interferometer mode that is used to measure current speeds. Typical image sizes for AIRSAR/TOPSAR products are 12 km x 12 km, with 10-m resolution in both dimensions. Topographic map products generated by the TOPSAR system have been shown to have a height accuracy of 1 m in relatively flat areas and 5 m in mountainous areas. 4.2.1.1 Tolerance Each image contains detailed calibration information in the header information area. 4.2.2 Frequency of Calibration Much of the data produced by the AIRSAR are now calibrated, so that the radar backscatter measurements are in normalized radar cross-section format (m2/m2) or ?? (sigma zero). Sigma zero is the radar cross-section (measured in m2) normalized by the area of the measurement, which in this case is the pixel area in square meters. 4.2.3 Other Calibration Information Two types of complementary calibration techniques are used for AIRSAR data calibration: internal calibration and external calibration. For the internal calibration, the information collected from the system tests that are performed regularly during the flight is used to obtain calibration parameters to be used in the AIRSAR processor. This will ensure that all the polarization channels are calibrated relative to one another at each frequency. For external calibration, which calibrates the radar cross-section of the scene absolutely and removes channel imbalance and the cross-talk, information from the scene and dihedral corner reflectors as external targets is used. Investigators who are interested in checking the accuracy of the calibration and performing other corrections themselves can request a copy of the POLCAL software and the user's manual directly from JPL. 5. Data Acquisition Methods The AIRSAR system acquires data during flights of the DC-8 aircraft. The instrument system acquires the data across the various spatial elements while the aircraft motion provides the forward motion for image acquisition. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes None given. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The BOREAS AirSAR CM Level-3b images cover sections of the Northern and the Southern Study Areas (NSA and SSA). The SSA and the NSA are located in the southwest and northeast portions of the overall BOREAS region. Each image covers a 12-km along-track and 10-km across-track area. The images contain 1,280 pixels in each of the approximately 5,000 lines. Most of the BOREAS AIRSAR level-3b CM imagery is over the SSA. There are two early season dates of level-3b SY imagery of the Northern Study Area (NSA). The SSA and the NSA are located in the southwest and northeast portions of the overall region. The North American Datum of 1983 (NAD83) corner coordinates of the SSA are: Latitude Longitude -------- --------- Northwest 54.321 N 106.228 W Northeast 54.225 N 104.237 W Southwest 53.515 N 106.321 W Southeast 53.420 N 104.368 W The NAD83 corner coordinates of the NSA are: Latitude Longitude -------- --------- Northwest 56.249 N 98.825 W Northeast 56.083 N 97.234 W Southwest 55.542 N 99.045 W Southeast 55.379 N 97.489 W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution Resolution in range: 6.66 m (across-track) Resolution in azimuth: 12.27 m. (along-track) 7.1.4 Projection The Remote Sensing Science (RSS)-16 team informed BORIS personnel that the images have been resampled into a regular spatial grid; however, the details of the projection used are not known. 7.1.5 Grid Description The RSS-16 team informed BORIS personnel that the images have been resampled into a regular spatial grid; however, the details of the gridding are not known. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The AIRSAR CM level-3b data were collected during concentrated periods from 12- Aug-1993 to 31-Jul-1995. 7.2.2 Temporal Coverage Map Date Study Area 12-AUG-93 SSA 11-JUN-94 SSA 17-APR-94 NSA 17-APR-94 SSA 20-APR-94 NSA 21-JUL-94 SSA 22-APR-94 SSA 23-JUL-94 SSA 26-APR-94 SSA 28-JUL-94 SSA 31-JUL-95 SSA 7.2.3 Temporal Resolution Most of the SSA Modeling Sub-Area (MSA) was covered by the AIRSAR CM images on two or three occasions from 12-Aug-1993 to 31-Jul-1995. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (airscm3b.def). 7.3.1 Parameter/Variable The data files contain a mixture of character and binary components. The user is encouraged to contact JPL personnel for detailed format descriptions. For the most part, the actual image data are INTEGER*2 in a format compatible with Sun computer systems. 7.3.2 Variable Description/Definition To translate the integer*2 values supplied in the file to radar cross-sections, one has to apply the following calculation: (DN^2)/(General scale factor) where the General scale factor is the general scale factor supplied in field 2 of the calibration header. 7.3.3 Unit of Measurement The image values are stored as the amplitude, i.e. as the square root of the power reflected back from the target. 7.3.4 Data Source The imagery were collected by the AIRSAR sensor aboard the NASA DC-8 research aircraft and were processed and provided by the Radar Data Center at the Jet Propulsion Laboratory, Pasadena, California. 7.3.5 Data Range Typically radar images exhibit a dynamic range less than 30 dB. Therefore each data set is scaled by a single value for all pixels such that the dynamic range of the total power elements in the Stokes matrices falls within values between 2-128 and 2127. The total power for each matrix is then coded into two bytes, one for the exponent in the above range and one for the mantissa. The other eight elements stored in the 10-byte sample are then normalized. 7.4 Sample Data Record Sample data format shown in the companion data definition file (airscm3b.def). 8. Data Organization 8.1 Data Granularity The smallest unit of data tracked by BORIS was a particular level-3b CM image. 8.2 Data Format(s) The image inventory data file contains numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (airscm3b.def). Prior to 1998, the AIRSAR data received by BORIS were in a single format. Starting in 1998, several scenes were received in a new format. Both of these formats are described in the following sections. Since detailed format information on the AirSAR data is available from JPL, BORIS personnel have not provided an exhaustive description of the data here. Please contact JPL personnel for further details. 8.2.1 Pre-1998 Data Format A level-3b AIRSAR CM image from BORIS is contained in three files, one file for each of the P, L, and C frequency bands, respectively. Each record of a level- 3b AIRSAR CM data file contains 10,240 bytes. The first three records in each file contain header information. The number of data records in a file varies depending on the length of the flight line. Each data record of 10,240 bytes contains a portion of the compressed Stokes matrix data. More specific information is as follows: FILE 1 (10,240-byte records for the P-band) - JPL AIRSAR New Header Record (Record 1) * 20 records, each containing 50 American Standard Code for Information Interchange (ASCII) characters. * 9,240 fill bytes. - JPL AIRSAR Old Header Record (Record 2) * 64 records, each containing 50 ASCII characters. * 7,040 fill bytes. - JPL AIRSAR Parameter Header Record (Record 3) * 87 records, each containing 50 ASCII characters. * 5,890 fill bytes. - JPL AIRSAR CM Compressed Stokes matrix data records (Record 4 to end of file) FILE 2 (10,240-byte records for the L-band) - JPL AIRSAR New Header Record (Record 1) * 20 records, each containing 50 ASCII characters. * 9,240 fill bytes. - JPL AIRSAR Old Header Record (Record 2) * 64 records, each containing 50 ASCII characters. * 7,040 fill bytes. - JPL AIRSAR Parameter Header Record (Record 3) * 87 records, each containing 50 ASCII characters. * 5,890 fill bytes. - JPL AIRSAR CM Compressed Stokes matrix data records (Record 4 to end of file) FILE 3 (10,240 byte records for the C-band) - JPL AIRSAR New Header Record (Record 1) * 20 records, each containing 50 ASCII characters. * 9,240 fill bytes. - JPL AIRSAR Old Header Record (Record 2) * 64 records, each containing 50 ASCII characters. * 7,040 fill bytes. - JPL AIRSAR Parameter Header Record (Record 3) * 87 records, each containing 50 ASCII characters. * 5,890 fill bytes. - JPL AIRSAR CM Compressed Stokes matrix data records (Record 4 to end of file) 8.2.2 1998 Data Format During 1998, the following scenes were received in a new file format (described below): 17-APR-94:18:25:49 17-APR-94:18:44:45 20-APR-94:19:38:05 11-JUN-94:19:58:23 11-JUN-94:20:11:07 31-JUL-95:18:34:00 The physical record length is 1024 or 10,240 bytes; the logical record length for one line of data is documented as being variable, but all the scenes in these sets of data are 25,600 bytes. “Records” mentioned below are logical records. FILE 1 (the entire scene, headers and image data, is contained in a single file) C-band records: - JPL AIRSAR New Header Record (Logical Record 1) * 20 records, each containing 50 ASCII characters. * Remainder of the logical record (24,600 bytes) is filler. - JPL AIRSAR Parameter Header Record (Logical Record 2) * 100 records, each containing 50 ASCII characters. * Remainder of record (20,600 bytes) is filler. - JPL AIRSAR Calibration Header Record (Logical Record 3) * 20 records, each containing 50 ASCII characters. * Remainder of record (24,600 bytes) is filler. - JPL AIRSAR CM Compressed Stokes matrix data records (Logical Record 4 to the end of the band). The end of the band can be determined by using the first five parameters (logical record size, nHeader recs, nLines, nSamples, nBytes per sample) listed in the New Header Record: logical rec size * (nHeader recs - # already read(3)) + nLines * nSamples * nBytes per sample ---------------------------------------------------- Physical Record Size Example: 25600 * (6-3) + 6699 * 2560 * 10 -------------------------------- 1024 L-band records: - JPL AIRSAR New Header Record (Logical Record 1) * 20 records, each containing 50 ASCII characters. * Remainder of the logical record (24,600 bytes) is filler. - JPL AIRSAR Parameter Header Record (Logical Record 2) * 100 records, each containing 50 ASCII characters. * Remainder of record (20,600 bytes) is filler. - JPL AIRSAR Calibration Header Record (Logical Record 3) * 20 records, each containing 50 ASCII characters. * Remainder of record (24,600 bytes) is filler. - JPL AIRSAR CM Compressed Stokes matrix data records (Logical Record 4 to the end of the band). The end of the band can be determined by using the first five parameters (logical record size, nHeader recs, nLines, nSamples, nBytes per sample) listed in the New Header Record: logical rec size * (nHeader recs - # already read(3)) + nLines * nSamples * nBytes per sample ---------------------------------------------------- Physical Record Size P-band records: - JPL AIRSAR New Header Record (Logical Record 1) * 20 records, each containing 50 ASCII characters. * Remainder of the logical record (24,600 bytes) is filler. - JPL AIRSAR Parameter Header Record (Logical Record 2) * 100 records, each containing 50 ASCII characters. * Remainder of record (20,600 bytes) is filler. - JPL AIRSAR Calibration Header Record (Logical Record 3) * 20 records, each containing 50 ASCII characters. * Remainder of record (24,600 bytes) is filler. - JPL AIRSAR CM Compressed Stokes matrix data records (Logical Record 4 to the end of the band). The end of the band can be determined by using the first five parameters (logical record size, nHeader recs, nLines, nSamples, nBytes per sample) listed in the New Header Record: logical rec size * (nHeader recs - # already read(3)) + nLines * nSamples * nBytes per sample ---------------------------------------------------- Physical Record Size 9. Data Manipulations 9.1 Formulae None. 9.1.1 Derivation Techniques and Algorithms None given. 9.2 Data Processing Sequence 9.2.1 Processing Steps BORIS staff makes the AIRSAR CM level-3b images available by: 1) Duplicating the JPL delivered images for backup purposes. 2) Extracting pertinent header information from the images for use in inventorying the level-3b image by date and time in the online data base. 3) Reviewing the content of the extracted header information for potential problems/anomlies. 4) Loading the needed information into the online data base. 9.2.2 Processing Changes In early 1998, a problem was found in the AIRSAR Integrated Processor Versions 5.01 and 5.02. This problem affected the backscatter cross section ?? values in some of the BOREAS products. The data that BORIS has archived does not reflect the changes made in the processor software to correct the problem. The corrected data has been delivered to ORNL and will be made available. The BOREAS data affected by the problem are identified in the following table. Date Study Area Product ID 17-APR-94 NSA CM5163 17-APR-94 NSA CM5165 17-APR-94 NSA CM5181 20-APR-94 NSA CM5182 31-JUL-95 SSA CM5188 11-JUN-94 SSA CM5190 11-JUN-94 SSA CM5193 9.3 Calculations 9.3.1 Special Corrections/Adjustments None given. 9.3.2 Calculated Variables None given. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error None given. 10.2 Quality Assessment 10.2.1 Data Validation by Source None given. 10.2.2 Confidence Level/Accuracy Judgment None given. 10.2.3 Measurement Error for Parameters None given. 10.2.4 Additional Quality Assessments None given. 10.2.5 Data Verification by Data Center BORIS staff reviews the images using developed software that was designed based on data product format documents received from JPL. The software reads through the data products on tape and summarizes the contents in ASCII files on disk. These files are reviewed visually by BORIS personnel for anomalous items. 11. Notes 11.1 Limitations of the Data None given. 11.2 Known Problems with the Data The data are provided in two different formats (see Section 8.2). See also, notes in section 9.2.2. 11.3 Usage Guidance None given. 11.4 Other Relevant Information None given. 12. Application of the Data Set AIRSAR images are used to estimate surface parameters such as canopy water content, soil moisture, and stand biomass and density. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description BORIS staff developed software and command procedures to: 1) Check and extract information from level-3b AIRSAR CM images on tape and write the information to ASCII files on disk for both data formats. 2) Read the ASCII disk file and log the level-3b AIRSAR CM images into the Oracle data base tables. The software mentioned under items 1 and 2 is written in the C language and is operational on VAX 6410 and MicroVAX 3100 systems at Goddard Space Flight Center (GSFC). The primary dependencies in the software are the tape input/output (I/O) library and the Oracle data base utility routines. 14.2 Software Access All of the described software is available upon request. See Section 15.4. BORIS staff would appreciate knowing of any problems discovered with the software, but cannot promise to fix them. 15. Data Access 15.1 Contact Information Ms. Beth Nelson BOREAS Data Manager NASA GSFC Greenbelt, MD (301) 286-4005 (301) 286-0239 (fax) Elizabeth.Nelson@gsfc.nasa.gov 15.2 Data Center Identification See Section 15.1. 15.3 Procedures for Obtaining Data Users may place requests by telephone, electronic mail, or fax. 15.4 Data Center Status/Plans The RSS-16 level-3b AirSAR CM data are available from the Earth Observing System Data and Information System (EOSDIS), Oak Ridge National Laboratory (ORNL), Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory Oak Ridge, TN (423) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 16. Output Products and Availability 16.1 Tape Products The AIRSAR level-3b CM data can be made available on 8-mm or Digital Archive Tape (DAT) media. 16.2 Film Products None. 16.3 Other Products During the data acquisition flight, 35-mm photographs were taken of the areas imaged by the AIRSAR system. Anyone interested in these photographs should contact Dr. Sasan Saatchi (See Section 2.3.) 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation NASA JPL. Date unknown. “AIRSAR Data Formats”, Chap 4. NASA JPL, 1995. AIRSAR Integrated Processor Documentation: DATA FORMATS. Version 0.01. Freeman, T. 1998. What is Imaging Radar? JPL Imaging Radar, (). 17.2 Journal Articles and Study Reports Sellers, P., and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P., and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue. Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J.Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. van Zyl, J. 1992. The AIRSAR System, JPL document. van Zyl, J. 1995. AIRSAR Integrated Processor Documentation, Version 0.01, April 21. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms AIRSAR - Airborne Synthetic Aperture Radar ASCII - American Standard Code for International Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BPI - Bytes per inch CCT - Computer Compatible Tape CM - Compressed Matrix DAAC - Distributed Active Archive Center DAT - Digital Archive Tape EOS - Earth Observing System EOSDIS - EOS Data and Information System GMT - Greenwich Mean Time GSFC - Goddard Space Flight Center JPL - Jet Propulsion Laboratory NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park RSS - Remote Sensing Science SAR - Synthetic Airborne Radar SSA - Southern Study Area SY - Synoptic TOPSAR - Topographic SAR URL - Uniform Resource Locator 20. Document Information 20.1 Document Revision Dates Written: 31-Jul-1995 Last Updated: 10-Jun-1998 20.2 Document Review Date BORIS Review: 17-Mar-1998 Science Review: 20.3 Document ID 20.4 Citation The AIRSAR data were provided by the Radar Data Center at NASA’s Jet Propulsion Laboratory. 20.5 Document Curator 20.6 Document URL Keywords SAR Radar JPL AIRSAR RSS16_AIRSAR_CM.doc Page 16 of 1 06/11/98