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Instruments > Earth Remote Sensing Instruments > Active Remote Sensing > Scatterometers > SASS

Preferred term

SASS  

Definition

  • A scatterometer provides the backscatter cross-section as a function of incidence angle for the area under observation. In the case of the SASS, the main interest was in measuring the ocean surface backscatter as a means to derive the surface wind vector. The physical basis for this technique is that the strength of the radar backscatter is proportional to the amplitude of the surface capillary waves (Bragg scattering), which in turn is related the wind speed near the surface. Moreover, the radar backscatter is anisotropic, allowing the wind direction to be derived from backscatter measurements at different azimuth angles. In practice, however, there was normally a fourfold ambiguity in the wind direction that had to be resolved manually. The SASS operated at a frequency of 14.6 GHz (or 2.0 cm). It incorporated four dual-polarized fan beam antennas, two radiating +/- 45 degrees forward and two, +/- 45 degrees aft, which produced an X-shaped pattern of illumination on the surface. Global measurements of the surface wind velocity over the seas were obtained from SASS at least once every 36 hours with the high latitudes being covered more frequently. The resolution of the instrument was 50 km and the grid spacing of the output data product, 100 km. ___________ Taken from: Elachi,C., 'Microwave and Infrared Satellite Remote Sensors,' in MANUAL OF REMOTE SENSING, edited by R.N.Colwell, pp 571-650, American Society of Photogrammetry, Sheridan Press, Falls Church, Virginia, 1983. ISBN 0-937294-41 Cornillon, P., A GUIDE TO ENVIRONMENTAL SATELLITE DATA, Graduate School of Oceanography, U. Rhode Island, Technical Report 79, 1982. _________ See Also: Special Issue on the SEASAT-1 Sensors, IEEE JOURNAL OF OCEANIC ENGINEERING, Vol. OE-5, No.2, 1980. Additional information on the SEASAT-1 spacecraft and the sensor available at "http://nsidc.org/data/docs/daac/seasat_platform.gd.html" Group: Instrument_Details Entry_ID: SASS Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Active Remote Sensing Instrument_Type: Scatterometers Short_Name: SASS Long_Name: SEASAT-A Scatterometer System End_Group Group: Associated_Platforms Short_Name: SEASAT 1 End_Group Online_Resource: http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1978-064A-03 End_Group (en)

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https://gcmd.earthdata.nasa.gov/kms/concept/06286aad-e656-4a8c-bc43-ffc2a1fdd281

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