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The special sensor microwave/imager (SSM/I) is a seven-channel, four-frequency, linearly polarized passive microwave radiometer system.〔Hollinger, J.P. 1989: ''DMSP Special Sensor Microwave/Imager Calibration/Validation''. Final Report, Vol. I., Space Sensing Branch, Naval Research Laboratory, Washington D.C.〕 It is flown on board the United States Air Force Defense Meteorological Satellite Program (DMSP) Block 5D-2 satellites. The instrument measures surface/atmospheric microwave brightness temperatures (TBs) at 19.35, 22.235, 37.0 and 85.5 GHz. The four frequencies are sampled in both horizontal and vertical polarizations, except the 22 GHz which is sampled in the vertical only.〔(【引用サイトリンク】url=http://www.ncdc.noaa.gov/oa/rsad/ssmi/gridded/index.php )〕 The SSM/I has been a very successful instrument, superseding the across-track and Dicke radiometer designs of previous systems. Its combination of constant-angle rotary-scanning and total power radiometer design has become standard for passive microwave imagers, e.g. TRMM Microwave Imager, AMSR. Its predecessor, the scanning multichannel microwave radiometer (SMMR), provided similar information. Its successor, the Special Sensor Microwave Imager / Sounder (SSMIS), is an enhanced eleven-channel, eight-frequency system. == Products == Along with its predecessor SMMR, the SSM/I contributes to an archive of global passive microwave products from late 1978 to present. Information within the SSM/I TBs measurements allow the retrieval of four important meteorological parameters over the ocean: near-surface wind speed (note scalar not vector), total columnar water vapor, total columnar cloud liquid water (liquid water path) and precipitation. Accurate and quantitative measurement of these parameters from the SSM/I TBs is, however, a non-trivial task. Variations within the meteorological parameters significantly modify the TBs. As well as open ocean retrievals, it is also possible to retrieve quantitatively reliable information on sea ice,〔(【引用サイトリンク】first=Suraiya )〕 land snow cover and over-land precipitation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Special sensor microwave/imager」の詳細全文を読む スポンサード リンク
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