Gridded SSM/I Products have been suspended as of November 2009 due to instrument failures. SSMIS data from F-16 and F-17 satellites are now being used.
Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager Sounder (SSMIS) Global Gridded Products
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. At present, NESDIS receives data from the F-15 satellite only; however, its channels have been deemed unusable for climate products as of January 2010.
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).
Scientists at the NOAA/NESDIS Center for Satellite Applicatons and Research (STAR) are actively involved in SSM/I and SSMIS algorithm development and validation, and the application of such algorithms for weather forecasting and analysis and climate evaluation. Please visit STAR's Microwave Integrated Retrieval System (MIRS) web site for more information.
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.