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SSMI(S) Hydrological Products

Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager Sounder (SSMIS) Hydrological Productsimage of World Rainfall for May 2010 from Satellite

The Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) is a seven channel passive microwave radiometer operating at four frequencies (19.35, 22.235, 37.0, and 85.5 GHz) and dual-polarization (except at 22.235 GHz which is V-polarization only). SSM/I data became operational in July 1987 on DMSP's F-8 satellite. Subsequent SSM/Is were flown on the DMSP's F-10 (November 1990), F-11 (December 1991), F-12 (August 1994), F-13 (March 1995), F-14 (April 1997) and most recently, F-15 (January 2000) satellites.

The SSM/I was replaced by an advanced sensor, the SSMIS (Special Sensor Microwave Imager Sounder), on the DMSP's F-16, F-17 and F-18 satellites, which became operational in November 2005, March 2008 and March 2010, respectively. SSMIS data is available through NOAA Data Centers' Comprehensive Large Array-data Stewardship System (CLASS). There has been little impact on the suite of hydrological products, as the primary channels used are almost identical for the SSM/I and SSMIS, the only exceptions being that the dual-polarized 85 GHz channels (SSM/I) were replaced with dual-polarized 91 GHz channels (SSMIS).

Monthly averaged SSM/I and SSMIS products include precipitation, cloud liquid water, total precipitable water, snow cover, and sea-ice extent. These products are useful for evaluating the mean climate state, its interannual and seasonal variations, and the detection of anomalies associated with large-scale (e.g. ENSO, Arctic Oscillation) and regional climatic variations. A time series of the entire SSM/I and SSMIS archive includes data from July 1987 to the present.