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Correction of WindScat Scatterometric Measurements by Combining with AMSR Radiometric DataThe Seawinds scatterometer on the advanced Earth observing satellite-2 (ADEOS-2) will determine surface wind vectors by measuring the radar cross section. Multiple measurements will be made at different points in a wind-vector cell. When dense clouds and rain are present, the signal will be attenuated, thereby giving erroneous results for the wind. This report describes algorithms to use with the advanced mechanically scanned radiometer (AMSR) scanning radiometer on ADEOS-2 to correct for the attenuation. One can determine attenuation from a radiometer measurement based on the excess brightness temperature measured. This is the difference between the total measured brightness temperature and the contribution from surface emission. A major problem that the algorithm must address is determining the surface contribution. Two basic approaches were developed for this, one using the scattering coefficient measured along with the brightness temperature, and the other using the brightness temperature alone. For both methods, best results will occur if the wind from the preceding wind-vector cell can be used as an input to the algorithm. In the method based on the scattering coefficient, we need the wind direction from the preceding cell. In the method using brightness temperature alone, we need the wind speed from the preceding cell. If neither is available, the algorithm can work, but the corrections will be less accurate. Both correction methods require iterative solutions. Simulations show that the algorithms make significant improvements in the measured scattering coefficient and thus is the retrieved wind vector. For stratiform rains, the errors without correction can be quite large, so the correction makes a major improvement. For systems of separated convective cells, the initial error is smaller and the correction, although about the same percentage, has a smaller effect.
Document ID
19960031918
Acquisition Source
Headquarters
Document Type
Contractor Report (CR)
Authors
Song, S. (Kansas Univ. Center for Research, Inc. Lawrence, KS United States)
Moore, R. K. (Kansas Univ. Center for Research, Inc. Lawrence, KS United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1996
Subject Category
Meteorology And Climatology
Report/Patent Number
NASA-CR-201451
RSL-TR-11960-1
NAS 1.26:201451
Accession Number
96N29910
Funding Number(s)
CONTRACT_GRANT: NS033A-04
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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