1. Data Set Overview:
-
Data Set Identification:
- SSM/I Derived Global Ocean Surface Wind Components (Atlas et al.)
(JPL PO.DAAC Product 079) -
Data Set Introduction:
- Product Number: 079
SSM/I Derived Global Ocean Surface Wind Components (Atlas et al.)Source/sensor: DMSP SSM/I, ECMWF wind analysis, ship and buoy reports
Coverage: July 1987 - December 1999, global (v.10)
Abstract:
This data set consists of surface wind vectors, nominally 10 m above the ocean surface, over the global oceans, between ± 78 degrees latitude, between July 1987 and December 1999.It is the latest of several products derived by R. Atlas and colleagues (Goddard Space Flight Center, GSFC), and Ross N. Hoffman (Atmospheric and Environmental Research - AER), whereby the wind vector field is obtained by combining frequent, global SSM/I-derived wind speeds with a background wind vector field from an atmospheric model plus scattered ship and buoy observation, and minimization constraints on the smoothness in space and time of the resulting field. The key input data are the frequent, global 10m wind speeds in 25 km footprints from SSM/I, on DMSP flights 8, 10, 11, and 14 as computed by F. Wentz using his version 2 SSM/I algorithms (Remote Sensing Systems, RSS; Wentz, 1997); these provide the f; a background field from the European Center for Medium Range Weather Forecast (ECMWF, on a 2.5 degree, 6 hour grid) 10 m wind analyses; and buoy data from the equatorial Pacific's TAO array, as well as scattered ship and buoy observations obtained organized at the National Center for Atmospheric Research and NOAA's National Center for Environmental Prediction. A Variational Analysis Method (VAM, Atlas et al., 1996; modified from Hoffman, 1984) yields a wind vector field that minimizes its sums of squared departures from ship and buoy data, from SSMI data, from background grids, and also minimizes the sums of squared speed, divergence, vorticity, and time derivative of vorticity.
This data product includes several datasets, identified by a 'level' number. Level 2.5 data sets contain swath SSM/I wind speeds, weight-averaged from their original 25 km samples to 75 km spatial bins, in 6 hour time bins, with their VAM-assigned directions. Level 3.0 contain the VAM output, uniform space-time gridded wind vectors, on a 2 deg latitude, 2.5 deg longitude, 6 hour grid. Level 3.5 product contains 5 day averages and monthly averages of the Level 2.5 data, on the same spatial grid as the level 3.0 data.
The gridded data (levels 3.0 and 3.5) are on the following grid:
rdata(i,j) i = 1,2,...,144 ==> lon = -180.0,-177.5,...,177.5 j = 1,2,...,91 ==> lat = -90.0,-88.0,...,90.0Documentation and software are available on line. The data sets are segmented by month.For more information, please see: http://www.ssmi.com.
Data Set Vol:
~6.3MB per month for Level 3.0 data ~25MB per month for Level 2.5 data ~0.1MB for Level 3.5 dataSmallest order: Entire data set unless accessed via FTP.
Std. Product: FTP or 8mm tape in UNIX TAR.
Data/Media Formats: Data is in HDF UNIX Tar. Data are provided on 8mm tape using UNIX Tar or via anonymous FTP to podaac.jpl.nasa.gov in the pub/ocean_wind/ssmi/atlas_ssmi_ver10/ directory.References:
Atlas, R., R.Hoffman, S.Bloom, J.Jusem, J.Ardizzone,1996: A Multi-year Global Surface Wind Velocity Data Set Using SSM/I Wind Observations. Bull. Amer. Meteor. Soc. May 1996, Vol.77, No.5, pp 869 - 882.Hoffman, R.N., 1984: SASS wind ambiguity removal by direct minimization. Part II: Use of smoothness and dynamical constraints., Monthly Weather Rev., 112, 1829-1852.
Wentz, F.J., 1997: A well-calibrated ocean algorithm for Special Sensor Microwaver/Imager, J. Geophys. Res., 102 (C4), pp8703-8718.
Notes: This product supersedes product 044 because it covers a longer period and uses Wentz's version-2 SSM/I data processing.
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Objective/Purpose:
- To provide a consistent set of wind vectors over the global oceans, starting in July 1987, while overcoming the inability of the passive microwave radiometer aboard DMSP SSM/I to measure wind direction.
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Summary of Parameters:
- East component of wind vector, in m/s (level 3 and 3.5)
North component of wind vector, in m/s (level 3 and 3.5)
Wind Speed, in m/s (level 2.5)
Wind direction, in degrees clockwise from North (level 2.5)
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Related Data Sets:
- The European Space Agency's ERS-1 satellite carries a one sided
scatterometer that measured wind vector over the global oceans starting
in late 1991. See http://www.ifremer.fr/cersat
- SSM/I DMSP F-8 ocean wind speed, liquid water, water vapor '87-'91 (Wentz) (JPL PO-DAAC Product 33), and from DMSP F10 (Product 34)
- The latest SSMI-only products are available from F. Wentz at http://www.ssmi.com
- SSM/I DMSP F-8 ocean wind speed, liquid water, water vapor '87-'91 (Wentz) (JPL PO-DAAC Product 33), and from DMSP F10 (Product 34)
2. Investigator(s):
-
Investigator(s) Name and Title:
- Dr. Robert Atlas, Data Assimilation Office. Laboratory for Atmospheres. NASA Goddard Space Flight Center, code 910.4, Greenbelt MD 20771. email:atlas@dao.gsfc.nasa.gov
-
Contact Information:
- Joseph Ardizzone
Data Assimilation Office, Laboratory for Atmospheres
NASA Goddard Space Flight Center
email: ardizzone@dao.gsfc.nasa.gov
3. Theory of Measurements:
4. Equipment:
-
Sensor/Instrument Description:
- 'The SSM/I sensor consists of seven separate total-power radiometers
sharing a common feedhorn. These seven radiometers take dual-polarization
measurements at 19.35, 37.0 and 85.5 Ghz, and just a vertical polarization
measurement at 22.235 Ghz. The SSM/I uses an offset parabolic reflector of
dimensions 61 by 66 cm to collect the microwave radiation. The reflector
focuses the radiation into the corrugated, broadband, seven port feedhorn.
The reflector and feedhorn spin as a unit about the nadir axis. The rotation
period is 1.9 s. A cold space reflector and a hot reference load are attached
to the spin axis and do not rotate. The rotating feedhorn observes the fixed
cold reflector and hot load once each scan. In this way, calibration
observastions are taken every scan' (verbatim from Wentz, 1997, copyright
American Geophysical Union).
'Earth observations are taken during a 102.4 degree segment of the rotation. The 102.4° arc is centered on the spacecraft subtrack, and corresponds to a 1400 km wide swath on the Earth's surface. The 1400 km swath and the orbit inclination of 98.8 degrees provide complete coverage of the Earth in 2 to 3 days, except for two small circular holes of 2.4 degrees centered on the North and South poles. The nadir angle for the Earth viewing reflector is 45 degrees, which results in an Earth incidence angle of 53.4 ± 0.25 degrees. The lower frequency channels (19, 22, and 37 Ghz) are sampled so that the pixel spacing is 25 km, and the 85 Ghz channels are sampled at a 12.5 km pixel spacing.' (verbatim from Wentz, 1997, copyright American Geophysical Union).
Further details on the SSM/I sensor can be found in the same reference (Wentz, 1997)
For descriptions of the sensors in the TAO buoys, please see http://www.pmel.noaa.gov/toga-tao.
The sensors in the various buoys and ship reports provided by NCAR and NCEP are unknown.
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Collection Environment:
- DMSP: Near-Earth orbit. The DMSP satellites fly in a near polar orbit
(98.8 degrees), at altitudes around 860 km.
TAO Buoys: moored at low latitude across the Equatorial Pacific.
Other buoys: ocean surface in the Atlantic ocean.
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Source/Platform:
- DMSP: Defense Meteorological Satellite Program satellites. The data
for this dataset came from three satellites: DMSP F8, DMSP F10, DMSP F11.
Their data availability is:
F08 SSM/I Jul 1987 to Dec 1991 F10 SSM/I Jan 1991 to present F11 SSM/I Jan 1992 to present F13 SSM/I May 1995 to present F14 SSM/I May 1997 to present -
Source/Platform Mission Objectives:
- DMSP: Operational U.S. Air Force meteorological sensing.
The mission of the DMSP is to provide global, visual and infrared
cloud data and other specialized near real-time meteorological,
oceanographic and solar-geophysical data required to support
worldwide Department of Defense operations and high-priority
programs. Timely data are supplied to Air Force Global Weather
Central, the Navy Fleet Numerical Oceanography Center and to
deployed tactical receiving terminals worldwide.
TAO: measure near-equatorial ocean currents, temperatures, and atmospheric forcing to aid in seasonal to interannual weather assessment.
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Key Variables:
- Wind Speed, Wind direction, East and North Wind components.
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Principles of Operation:
- See Sensor/Instrument Description
-
Sensor/Instrument Measurement Geometry:
- The scene is viewed over a scan angle of 102.4° centered
on the ground track aft of the satellite, resulting in a scene
swath width of 1394 km. The spatial resolution of the SSM/I
footprints vary from 13-70 km depending on the frequency. The
spatial sampling interval is 25 km for all frequencies, except
85.5 GHz, which is sampled at 12.5 km intervals.
SSM/I orbit and scan geometry from [Hollinger et al., 1987]
- See Sensor/Instrument Description
-
Manufacturer of Sensor/Instrument:
- Hughes Aircraft Company
-
Calibration:
- Atlas et al (1996) performed a systematic check of the level 3.0
data included here against TAO buoy observations witheld from the
VAM analysis, as well as against the SSM/I wind speeds and ECMWF
wind vectors. They concluded that the VAM level 3.0 differed from
the more accurate TAO buoys by 0.2 ± 1.4 m/s and -3.1 ± 20
degrees. It differed from the other buoy and ship reports by 0 ±
2.6 m/s and 0 ± 20 degrees. While the difference from the ECMWF
background field was larger, it is to be expected simply from the
absence of direct observation of winds over huge parts of the ocean
to constrain the model. Of course, these values include a certain
level of energy just due to the difference in time and location
between in-situ and VAM estimates, a difference Atlas et al. did
not attempt to estimate.
Wentz (1997) in turn calibrated his SSM/I wind speeds using selected buoys for the 1978-80 time period. He found about 1.3 m/s RMS difference and estimated at 0.94 m/s the RMS difference just due to the (small) space and time mismatch between SSM/I observation and in-situ observation.
5. Data Acquisition Methods:
6. Observations:
-
Data Notes:
- No additional notes.
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Field Notes:
- No additional notes.
7. Data Description:
-
Spatial Characteristics:
-
Spatial Coverage:
- This data product includes several datasets, identified by a
'level' number.
- Level 2.5 data sets contain alongtrack SSM/I wind speeds,
weight-averaged from their original 25 km samples to 75 km
spatial bins, in 6 hour time bins, with their VAM-assigned
directions.
- Level 3.0 contain the VAM output, uniform space-time
gridded wind vectors, on a 2 deg latitude, 2.5 deg longitude,
6 hour grid.
- Level 3.5 product contains 5 day averages and monthly
averages of the level 2.5 data, on the same spatial grid as
the level 3.0 data.
Extensions will be made as SSM/I data becomes available. All data sets contain North and East components of the wind in m/s at the reference 10 m height.
The gridded data (levels 3.0 and 3.5) are on the following grid:
rdata(i,j) i = 1,2,...,144 ==> lon = -180.0,-177.5,...,177.5 j = 1,2,...,91 ==> lat = -90.0,-88.0,...,90.0 - Level 2.5 data sets contain alongtrack SSM/I wind speeds,
weight-averaged from their original 25 km samples to 75 km
spatial bins, in 6 hour time bins, with their VAM-assigned
directions.
-
Spatial Coverage Map:
- One DMSP SSM/I satellite yields the 1-day coverage shown below.
When two satellites operate simultaneously, the daily coverage
is 100% within the latitude bounds.
-
Spatial Resolution:
- See Spatial Coverage
-
Projection:
- The level 3 and 3.5 data are on a linear latitude-longitude grid. The level 2.5 data are not on a regular grid.
-
Grid Description:
- See Spatial Coverage
-
-
Temporal Characteristics:
-
Temporal Coverage:
- July 1987 to December 1996. Although at times 2 or more satellites are observing, data gaps do occur and some days do not have SSM/I data.
-
Temporal Coverage Map:
- A tabular 'map' of time gaps follows:
F08 SSMI wind speed data were unavailable for the following times Date=870720 Time=18
Date=870721 Time=18
Date=870824 Time=18
Date=870825 Time=0
Date=870825 Time=6
Date=870825 Time=12
Date=870825 Time=18
Date=870826 Time=0
Date=870826 Time=6
Date=870826 Time=12
Date=870826 Time=18
Date=870827 Time=0
Date=870827 Time=6
Date=870827 Time=12
Date=871006 Time=0
Date=871006 Time=6
Date=871006 Time=12
Date=871006 Time=18
Date=871007 Time=0
Date=871007 Time=6
Date=871007 Time=12
Date=871007 Time=18
Date=871008 Time=0
Date=871009 Time=0
Date=871022 Time=12
Date=871022 Time=18
Date=871113 Time=0
Date=871201 Time=0
Date=871201 Time=6
Date=871201 Time=12
Date=871201 Time=18
Date=871202 Time=0
Date=871202 Time=6
Date=871202 Time=12
Date=871202 Time=18
Date=871203 Time=0
Date=871203 Time=6
Date=871203 Time=12
Date=871203 Time=18
Date=871204 Time=0
Date=871204 Time=6
Date=871204 Time=12
Date=871204 Time=18
Date=871205 Time=0
Date=871205 Time=6
Date=871205 Time=12
Date=871205 Time=18
Date=871206 Time=0
Date=871206 Time=6
Date=871206 Time=12
Date=871206 Time=18
Date=871207 Time=0
Date=871207 Time=6
Date=871207 Time=12
Date=871207 Time=18
Date=871208 Time=0
Date=871208 Time=6
Date=871208 Time=12
Date=871208 Time=18
Date=871209 Time=0
Date=871209 Time=6
Date=871209 Time=12
Date=871209 Time=18
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Date=871210 Time=6
Date=871210 Time=12
Date=871210 Time=18
Date=871211 Time=0
Date=871211 Time=6
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Date=871212 Time=6
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Date=871214 Time=0
Date=871214 Time=6
Date=871214 Time=12
Date=871214 Time=18
Date=871215 Time=0
Date=871215 Time=6
Date=871215 Time=12
Date=871215 Time=18
Date=871216 Time=0
Date=871216 Time=6
Date=871216 Time=12
Date=871216 Time=18
Date=871217 Time=0
Date=871217 Time=6
Date=871217 Time=12
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Date=871218 Time=0
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Date=871218 Time=12
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Date=871219 Time=12
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Date=871221 Time=12
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Date=871223 Time=12
Date=871223 Time=18
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Date=871224 Time=6
Date=871224 Time=12
Date=871224 Time=18
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Date=871225 Time=6
Date=871225 Time=12
Date=871225 Time=18
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Date=871226 Time=6
Date=871226 Time=12
Date=871226 Time=18
Date=871227 Time=0
Date=871227 Time=6
Date=871227 Time=12
Date=871227 Time=18
Date=871228 Time=0
Date=871228 Time=6
Date=871228 Time=12
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Date=871229 Time=0
Date=871229 Time=6
Date=871229 Time=12
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Date=901101 Time=18
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Date=910326 Time=0
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Date=910802 Time=12
Date=910806 Time=18
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Date=910816 Time=6
Date=911111 Time=0
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Date=911219 Time=6
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Date=911230 Time=6
Date=911230 Time=12
Date=911231 Time=0
Date=911231 Time=6
Date=911231 Time=12
F10 SSMI wind speed data were unavailable for the following times: Date=910101 Time=0
Date=910101 Time=6
Date=910101 Time=12
Date=910101 Time=18
Date=910102 Time=0
Date=910102 Time=6
Date=910102 Time=12
Date=910102 Time=18
Date=910103 Time=0
Date=910103 Time=6
Date=910103 Time=12
Date=910103 Time=18
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Date=910104 Time=6
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Date=910106 Time=12
Date=910106 Time=18
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Date=910107 Time=6
Date=910107 Time=12
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Date=910108 Time=18
Date=910109 Time=12
Date=910110 Time=6
Date=910111 Time=0
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Date=910111 Time=12
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Date=910112 Time=18
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Date=910113 Time=12
Date=910113 Time=18
Date=910114 Time=0
Date=910114 Time=6
Date=910114 Time=12
Date=910115 Time=0
Date=910115 Time=6
Date=910115 Time=12
Date=910116 Time=0
Date=910116 Time=6
Date=910117 Time=6
Date=910117 Time=18
Date=910118 Time=6
Date=910118 Time=18
Date=910119 Time=6
Date=910119 Time=18
Date=910120 Time=18
Date=910121 Time=6
Date=910122 Time=6
Date=910122 Time=18
Date=910123 Time=0
Date=910123 Time=6
Date=910124 Time=6
Date=910124 Time=18
Date=910125 Time=6
Date=910125 Time=18
Date=910126 Time=6
Date=910126 Time=18
Date=910127 Time=18
Date=910128 Time=6
Date=910128 Time=18
Date=910129 Time=6
Date=910129 Time=18
Date=910130 Time=6
Date=910130 Time=18
Date=910131 Time=6
Date=910131 Time=18
Date=910201 Time=0
Date=910201 Time=6
Date=910201 Time=18
Date=910202 Time=0
Date=910202 Time=6
Date=910202 Time=12
Date=910202 Time=18
Date=910203 Time=0
Date=910203 Time=6
Date=910203 Time=12
Date=910203 Time=18
Date=910204 Time=0
Date=910204 Time=6
Date=910204 Time=12
Date=910204 Time=18
Date=910205 Time=0
Date=910205 Time=6
Date=910205 Time=12
Date=910205 Time=18
Date=910206 Time=0
Date=910206 Time=6
Date=910206 Time=12
Date=910206 Time=18
Date=910207 Time=0
Date=910207 Time=6
Date=910207 Time=12
Date=910207 Time=18
Date=910208 Time=0
Date=910208 Time=6
Date=910208 Time=12
Date=910208 Time=18
Date=910209 Time=12
Date=910209 Time=18
Date=910210 Time=0
Date=910210 Time=6
Date=910210 Time=12
Date=910210 Time=18
Date=910211 Time=0
Date=910211 Time=6
Date=910211 Time=12
Date=910211 Time=18
Date=910212 Time=0
Date=910212 Time=6
Date=910212 Time=12
Date=910213 Time=6
Date=910214 Time=6
Date=910215 Time=6
Date=910216 Time=6
Date=910217 Time=0
Date=910217 Time=6
Date=910218 Time=0
Date=910218 Time=6
Date=910219 Time=6
Date=910220 Time=6
Date=910224 Time=6
Date=910224 Time=12
Date=910224 Time=18
Date=910225 Time=0
Date=910225 Time=6
Date=910225 Time=12
Date=910302 Time=6
Date=910303 Time=12
Date=910303 Time=18
Date=910304 Time=0
Date=910304 Time=6
Date=910304 Time=12
Date=910305 Time=18
Date=910307 Time=18
Date=910310 Time=0
Date=910310 Time=6
Date=910310 Time=12
Date=910310 Time=18
Date=910313 Time=0
Date=910313 Time=12
Date=910319 Time=18
Date=910325 Time=18
Date=910326 Time=0
Date=910326 Time=6
Date=910327 Time=6
Date=910327 Time=12
Date=910327 Time=18
Date=910328 Time=0
Date=910328 Time=6
Date=910328 Time=12
Date=910328 Time=18
Date=910329 Time=0
Date=910329 Time=6
Date=910329 Time=12
Date=910329 Time=18
Date=910330 Time=0
Date=910330 Time=6
Date=910330 Time=12
Date=910330 Time=18
Date=910331 Time=0
Date=910331 Time=6
Date=910331 Time=12
Date=910331 Time=18
Date=910401 Time=0
Date=910401 Time=6
Date=910401 Time=12
Date=910401 Time=18
Date=910402 Time=0
Date=910402 Time=6
Date=910402 Time=12
Date=910402 Time=18
Date=910403 Time=0
Date=910403 Time=6
Date=910403 Time=12
Date=910403 Time=18
Date=910404 Time=0
Date=910404 Time=6
Date=910404 Time=12
Date=910404 Time=18
Date=910405 Time=0
Date=910405 Time=6
Date=910405 Time=12
Date=910405 Time=18
Date=910406 Time=0
Date=910406 Time=6
Date=910406 Time=12
Date=910406 Time=18
Date=910407 Time=0
Date=910407 Time=6
Date=910407 Time=12
Date=910407 Time=18
Date=910408 Time=0
Date=910408 Time=6
Date=910408 Time=12
Date=910408 Time=18
Date=910409 Time=0
Date=910409 Time=6
Date=910409 Time=12
Date=910409 Time=18
Date=910410 Time=0
Date=910410 Time=6
Date=910410 Time=12
Date=910410 Time=18
Date=910411 Time=0
Date=910411 Time=6
Date=910411 Time=12
Date=910411 Time=18
Date=910412 Time=0
Date=910412 Time=6
Date=910412 Time=12
Date=910412 Time=18
Date=910413 Time=0
Date=910413 Time=6
Date=910413 Time=12
Date=910413 Time=18
Date=910414 Time=0
Date=910414 Time=6
Date=910414 Time=12
Date=910414 Time=18
Date=910415 Time=0
Date=910415 Time=6
Date=910415 Time=12
Date=910415 Time=18
Date=910416 Time=0
Date=910416 Time=6
Date=910416 Time=12
Date=910416 Time=18
Date=910417 Time=0
Date=910417 Time=6
Date=910417 Time=12
Date=910417 Time=18
Date=910418 Time=0
Date=910418 Time=6
Date=910418 Time=12
Date=910419 Time=6
Date=910419 Time=12
Date=910430 Time=0
Date=910430 Time=6
Date=910430 Time=12
Date=910508 Time=12
Date=910508 Time=18
Date=910509 Time=0
Date=910513 Time=12
Date=910517 Time=18
Date=910518 Time=0
Date=910519 Time=18
Date=910520 Time=6
Date=910520 Time=12
Date=910531 Time=12
Date=910602 Time=6
Date=910602 Time=12
Date=910610 Time=12
Date=910611 Time=6
Date=910611 Time=12
Date=910618 Time=6
Date=910623 Time=6
Date=910626 Time=12
Date=910628 Time=6
Date=910712 Time=0
Date=910714 Time=12
Date=910714 Time=18
Date=910715 Time=0
Date=910715 Time=6
Date=910718 Time=6
Date=910719 Time=0
Date=910719 Time=6
Date=910725 Time=0
Date=910725 Time=6
Date=910728 Time=6
Date=910728 Time=12
Date=910728 Time=18
Date=910729 Time=0
Date=910729 Time=6
Date=910729 Time=12
Date=910729 Time=18
Date=910730 Time=0
Date=910730 Time=6
Date=910730 Time=12
Date=910730 Time=18
Date=910731 Time=0
Date=910731 Time=6
Date=910731 Time=12
Date=910802 Time=12
Date=910806 Time=6
Date=910808 Time=0
Date=910808 Time=6
Date=910809 Time=6
Date=910810 Time=6
Date=910813 Time=6
Date=910814 Time=18
Date=910818 Time=6
Date=910823 Time=6
Date=910825 Time=6
Date=910826 Time=6
Date=910830 Time=6
Date=910903 Time=6
Date=910905 Time=6
Date=910906 Time=12
Date=910915 Time=6
Date=910916 Time=6
Date=910917 Time=6
Date=910922 Time=6
Date=910926 Time=0
Date=910926 Time=6
Date=911005 Time=12
Date=911006 Time=6
Date=911017 Time=12
Date=911102 Time=12
Date=911109 Time=6
Date=911109 Time=12
Date=911111 Time=0
Date=911112 Time=18
Date=911130 Time=6
Date=911205 Time=6
Date=911206 Time=6
Date=911206 Time=12
Date=911206 Time=18
Date=911207 Time=0
Date=911207 Time=6
Date=911207 Time=12
Date=911207 Time=18
Date=911208 Time=0
Date=911208 Time=6
Date=911208 Time=12
Date=911208 Time=18
Date=911209 Time=0
Date=911209 Time=6
Date=911209 Time=12
Date=911209 Time=18
Date=911210 Time=0
Date=911210 Time=6
Date=911210 Time=12
Date=911210 Time=18
Date=911211 Time=0
Date=911211 Time=6
Date=911211 Time=12
Date=911211 Time=18
Date=911212 Time=0
Date=911212 Time=6
Date=911212 Time=12
Date=911213 Time=0
Date=911213 Time=6
Date=911214 Time=0
Date=911214 Time=6
Date=911214 Time=12
Date=911214 Time=18
Date=911215 Time=0
Date=911215 Time=6
Date=911215 Time=12
Date=911215 Time=18
Date=911216 Time=0
Date=911216 Time=6
Date=911216 Time=12
Date=911216 Time=18
Date=911217 Time=0
Date=911217 Time=6
Date=911217 Time=12
Date=911217 Time=18
Date=911218 Time=0
Date=911218 Time=6
Date=920303 Time=18
Date=920606 Time=12
Date=920606 Time=18
Date=920607 Time=0
Date=920607 Time=6
Date=920607 Time=12
Date=920607 Time=18
Date=920608 Time=0
Date=920715 Time=0
Date=921226 Time=0
Date=930103 Time=18
Date=930104 Time=0
Date=930104 Time=6
Date=930104 Time=12
Date=930107 Time=12
Date=930219 Time=0
Date=930304 Time=18
Date=930423 Time=0
Date=930424 Time=0
Date=930424 Time=6
Date=930424 Time=12
Date=930424 Time=18
Date=930425 Time=0
Date=930425 Time=6
Date=930425 Time=12
Date=930425 Time=18
Date=930426 Time=6
Date=930426 Time=12
Date=930617 Time=12
Date=930908 Time=18
Date=931117 Time=18
Date=931209 Time=0
Date=931209 Time=6
Date=931209 Time=12
Date=931211 Time=6
Date=931211 Time=12
Date=931215 Time=6
Date=931215 Time=12
Date=931216 Time=18
Date=931217 Time=0
Date=931228 Time=6
Date=931228 Time=12
Date=940101 Time=12
Date=940102 Time=0
Date=940329 Time=6
Date=940509 Time=12
Date=940608 Time=0
Date=940619 Time=12
Date=940629 Time=0
Date=940717 Time=6
Date=940717 Time=12
Date=940717 Time=18
Date=940718 Time=0
Date=940718 Time=6
Date=940718 Time=12
Date=940718 Time=18
Date=940719 Time=0
Date=940719 Time=6
Date=940719 Time=12
Date=940719 Time=18
Date=940720 Time=0
Date=940720 Time=6
Date=940720 Time=12
Date=940720 Time=18
Date=940721 Time=0
Date=940721 Time=6
Date=940721 Time=12
Date=940721 Time=18
Date=940722 Time=0
Date=940722 Time=6
Date=940722 Time=12
Date=940722 Time=18
Date=940723 Time=0
Date=940723 Time=6
Date=940723 Time=12
Date=940723 Time=18
Date=940724 Time=0
Date=940724 Time=6
Date=940724 Time=12
Date=940724 Time=18
Date=940725 Time=0
Date=940725 Time=6
Date=940725 Time=12
Date=940725 Time=18
Date=940726 Time=0
Date=940726 Time=6
Date=940726 Time=12
Date=940726 Time=18
Date=940727 Time=0
Date=940727 Time=6
Date=940727 Time=12
Date=940727 Time=18
Date=940728 Time=0
Date=940728 Time=6
Date=940728 Time=12
Date=940728 Time=18
Date=940729 Time=0
Date=940729 Time=6
Date=940729 Time=12
Date=940920 Time=18
Date=940921 Time=6
Date=940921 Time=12
Date=941101 Time=12
Date=941213 Time=0
Date=941225 Time=12
F11 SSMI wind speed data were unavailable for the following times: Date=920214 Time=0
Date=920214 Time=6
Date=920215 Time=0
Date=920606 Time=12
Date=920606 Time=18
Date=920607 Time=0
Date=920607 Time=6
Date=920607 Time=12
Date=920607 Time=18
Date=920617 Time=12
Date=920617 Time=18
Date=920618 Time=0
Date=920618 Time=6
Date=920618 Time=12
Date=920618 Time=18
Date=920619 Time=0
Date=920715 Time=0
Date=920716 Time=6
Date=920903 Time=0
Date=920903 Time=6
Date=921001 Time=18
Date=921106 Time=18
Date=921207 Time=6
Date=921213 Time=18
Date=921222 Time=6
Date=921222 Time=12
Date=921230 Time=12
Date=921230 Time=18
Date=921231 Time=0
Date=921231 Time=6
Date=930104 Time=0
Date=930104 Time=6
Date=930104 Time=12
Date=930104 Time=18
Date=930105 Time=0
Date=930108 Time=6
Date=930118 Time=0
Date=930301 Time=18
Date=930311 Time=0
Date=930311 Time=6
Date=930311 Time=12
Date=930713 Time=18
Date=931117 Time=18
Date=931209 Time=0
Date=931209 Time=6
Date=931209 Time=12
Date=931211 Time=6
Date=931211 Time=12
Date=931216 Time=18
Date=931217 Time=0
Date=931228 Time=6
Date=931228 Time=12
Date=940101 Time=12
Date=940217 Time=12
Date=940608 Time=0
Date=940629 Time=0
Date=940720 Time=6
Date=940720 Time=12
Date=940720 Time=18
Date=940721 Time=0
Date=940721 Time=6
Date=940721 Time=12
Date=940722 Time=6
Date=940722 Time=12
Date=941111 Time=18
Date=941120 Time=0
Date=941120 Time=6
Date=941120 Time=12
Date=941120 Time=18
Date=941121 Time=0
Date=941121 Time=6
Date=941121 Time=12
Date=941121 Time=18
Date=941122 Time=0
Date=941122 Time=6
Date=941122 Time=12
Date=941213 Time=0
-
Temporal Resolution:
- See Spatial Coverage
-
-
Data Characteristics:
-
Parameter/Variable:
- North Wind Component, meters/sec
- East Wind Component, meters/sec
- Wind Speed, meters/sec
- Wind Direction, degrees clockwise from North.
The winds are given at the reference height of 10 m.
-
-
Sample Data Record:
Enter HDF filename: atlas.ssmi.ver02.level2.5.jan93.hdf Dataset Name is VAM SSMI F10F11 Current date/time is 930101 0 LATSSTNDHGHT 10: -62.97821 62.95599 8204 0 LONSSTNDHGHT 10: -179.9891 179.9947 8204 0 UWNDSTNDHGHT 10: -18.93246 24.92874 8204 0 VWNDSTNDHGHT 10: -17.79962 19.43052 8204 0 Current date/time is 930101 60000 LATSSTNDHGHT 10: -62.99765 72.88998 9817 8204 LONSSTNDHGHT 10: -179.9947 179.9947 9817 8204 UWNDSTNDHGHT 10: -24.15235 21.42033 9817 8204 VWNDSTNDHGHT 10: -19.31577 18.45027 9817 8204 Current date/time is 930101 120000 LATSSTNDHGHT 10: -62.98932 72.92886 10845 18021 LONSSTNDHGHT 10: -171.6150 152.3147 10845 18021 UWNDSTNDHGHT 10: -17.48466 18.68465 10845 18021 VWNDSTNDHGHT 10: -15.14695 18.00348 10845 18021 Current date/time is 930101 180000 LATSSTNDHGHT 10: -62.89767 72.98996 2425 28866 LONSSTNDHGHT 10: -179.9781 179.9947 2425 28866 UWNDSTNDHGHT 10: -17.60430 21.80975 2425 28866 VWNDSTNDHGHT 10: -20.36561 20.69033 2425 28866
8. Data Organization:
-
Data Granularity:
- A general description of data granularity as it applies
to the Earth Observing System Data Gateway appears in the
EOSDIS Glossary.
- The level 3 and 3.5 granule is one daily, 5 day or monthly map.
-
Data Format:
- Data is in HDF (Hierarchical Data Format) UNIX Tar.
9. Data Manipulations:
-
Formulae:
Derivation Techniques and Algorithms:
- See Atlas et al., 1996
-
Data Processing Sequence:
- See Atlas et al., 1996
-
Calculations:
-
Special Corrections/Adjustments:
- See Atlas et al., 1996
-
Calculated Variables:
- Wind components
-
-
Graphs and Plots:
- None
10. Errors:
-
Sources of Error:
- See Wentz, 1997.
-
Quality Assessment:
- See Atlas et al., 1996
11. Notes:
-
Limitations of the Data:
- No additional information.
-
Known Problems with the Data:
- Not known.
-
Usage Guidance:
- See Atlas et al., 1996
-
Any Other Relevant Information about the Study:
- None
12. Application of the Data Set:
13. Future Modifications and Plans:
14. Software:
-
Software Description:
The following software, test inputs and outputs, are available with the IDF version of the data: Makefile 245 bytes Fri Mar 8 00:00:00 1996 README 2 Kb Fri Mar 8 00:00:00 1996 idf.doc.ps 29 Kb Fri Mar 8 00:00:00 1996 Postscript Document idfio.f 12 Kb Wed Feb 7 00:00:00 1996 idftest.f 5 Kb Wed Feb 7 00:00:00 1996 idfutil.f 1 Kb Wed Feb 7 00:00:00 1996 pack.f 23 Kb Wed Feb 7 00:00:00 1996 test.dgla 102 Kb Mon Mar 11 00:00:00 1996 test.output 438 bytes Fri Mar 8 00:00:00 1996 test.tgla 704 bytes Mon Mar 11 00:00:00 1996 The following software, test inputs and outputs, are available with the HDF version of the data: Makefile 235 bytes Wed Jun 26 00:00:00 1996 README 2 Kb Fri Mar 8 00:00:00 1996 gzip-1.2.4.tar.Z 320 Kb Fri Mar 8 00:00:00 1996 application/x-compressed hdf.doc.ps 111 Kb Fri Mar 8 00:00:00 1996 Postscript Document hdftest.f 9 Kb Thu Mar 7 00:00:00 1996 test.hdf 113 Kb Fri Mar 8 00:00:00 1996 test.output 409 bytes Fri Mar 8 00:00:00 1996
Software Access:
-
ftp://podaac.jpl.nasa.gov/pub/ocean_wind/ssmi/atlas_ssmi_ver10/
15. Data Access:
-
Contact Information:
- User Services Office
Physical Oceanography Distributed Active Archive Center (PO.DAAC)
Jet Propulsion Laboratory (JPL)Phone: (626) 744-5508
Fax: (626) 744-5506
Email: podaac@podaac.jpl.nasa.gov
URL: http://podaac.jpl.nasa.gov
-
Data Center Identification:
- Jet Propulsion Laboratory (JPL)
Physical Oceanography Archive Center (PO.DAAC)
-
Procedures for Obtaining Data:
- Data are available through the PO.DAAC anonymous ftp site:
ftp podaac.jpl.nasa.gov
name: anonymous
password: use email address
cd /pub/ocean_wind/ssmi/derived_windsTo order data on 8mm tapes, please contact the User Services Office.
-
Data Center Status/Plans:
- PO-DAAC is the primary NASA archive for physical oceanographic satellite data and derived products, and will continue to acquire wind data over the oceans from this and other sources.
16. Output Products and Availability:
17. References:
Hoffman, R.N., 1984. SASS wind ambiguity removal by direct minimization. Part II: Use of smoothness and dynamical constraints., Monthly Weather Rev., 112, 1829-1852.
Hollinger, J.P., J.L. Peirce, G.A. Poe, 1990. SSM/I instrument evaluation. IEEE Transactions on Geoscience and Remote Sensing, 28(5), 781-790.
Hollinger J.P., 1989. "DMSP Special Sensor Microwave/Imager calibration/validation," NRL Tech. Rep., Naval Research Laboratory, Washington D.C.
Liu, W.T., W. Tang and R. Atlas, 1996. Responses of the tropical Pacific to wind forcing as observed by spaceborne sensors and simulated by an ocean general circulation model. J. Geophys. Res., 101, p16,345-16,359.
Wentz, F.J., 1997. A well-calibrated ocean algorithm for Special Sensor Microwaver/Imager, J. Geophys. Res., 102 (C4), pp8703-8718.
Wentz, F.J., 1992. Measurement of Oceanic Wind Vector Using Satellite Microwave Radiometers, IEEE Transactions on Geoscience and Remote Sensing, 30(5), 960-972.
Wentz, F.J., 1992. "Revision-1 Update For SSM/I Geophysical Tapes User's Manual," RSS Technical Report 040792, Remote Sensing Systems, Santa Rosa, CA, 11 pp.
Wentz, F.J., 1989. "User's Manual SSM/I Geophysical Tapes, "RSS Technical Report 060989, Remote Sensing Systems, Santa Rosa, CA, 16 pp.
Wentz, F.J., 1988. "User's Manual SSM/I Antenna Temperature Tapes, "RSS Technical Report 032588, Remote Sensing Systems, Santa Rosa, CA, 36 pp.
Wentz, F.J., L.A. Mattox, and S. Peteherych, 1986. New algorithms for microwave measurements of ocean winds: Applications to SEASAT and the Special Microwave Imager, J. Geophys. Res., 91(C2), 2289-2307.
18. Glossary of Terms:
- DMSP
- A series of spacecraft controlled by the Defense Meteorology
Satellite Program which originated as a long-term U.S. Air
Force effort but are now declassified.
- SSM/I
- Special Sensor Microwave Imager, flown on board the DMSP-F8, is
designed to measure ocean surface wind speed, ice coverage and
age, cloud water content, rainfall and atmospheric vertical
temperature and humidity profiles.
- Wind Speed
- Scalar value of the magnitude of the wind speed at the surface,
in meters per second.
19. List of Acronyms:
- DMSP Defense Meteorological Satellite Program
- HDF Hierarchical Data Format
- IDF IRIS Data Format
- JPL Jet Propulsion Laboratory
- MSFC Marshall Space Flight Center
- NASA National Aeronautics and Space Administration
- NOAA National Oceanic and Atmospheric Administration
- SSM/I Special Sensor Microwave/Imager
- URL Uniform Resource Locator
20. Document Information:
-
Document Revision Date:
- 6 August 1997 (V. Zlotnicki)
-
Document Review Date:
- 2 April 1998 (K. Case)
-
Document ID:
-
Citation:
-
Document Curator:
- PO.DAAC User Services Office
-
Document URL:
- http://podaac.jpl.nasa.gov:2031/DATASET_DOCS/ssmi_atlas_wind.html