20 YEARS OF HYDROLOGICAL PRODUCTS FROM THE SSM/I: STATUS AND FUTURE

It’s hard to believe, but the Special Sensor Microwave/Imager (SSM/I) has been in operation for 20 years. As the first operational passive microwave imager, the SSM/I continues to provide unprecedented information to weather forecasters, NWP modelers, and to the climate community. Parameters such as rain rate, total precipitable water and snow cover are now used 24 hour/day, 7 day/week by all of the operational weather/climate centers throughout the world. In addition, the algorithms and product generation systems that have resulted from years of research and development with the SSM/I have served as prototypes to similar product suites that are being delivered through other microwave sensors, such as those flown on the TRMM (e.g., TMI), Aqua (e.g., AMSR-E), NOAA and METOP satellites (e.g., AMSU/MHS). NOAA/NESDIS has been generating global, monthly mean hydrological products from the SSM/I for over a decade. These products are archived at NESDIS ’ National Climatic Data Center (NCDC) and are utilized by several operational agencies (i.e., NOAA, JMA, ECMWF, etc.), are integral parts of international projects (e.g., Global Precipitation Climatology Project- GPCP), and by academia for innovative research. NOAA is committed to continue the generation of such products for the foreseeable future. It is the purpose of this paper to highlight some of the key scientific accomplishments demonstrated by the 20-year time series. The SSM/I is being “updated ” by the SSM/IS (Imager/Sounder), a combination/enhancement of the previous SSM/I, SSM/T and SSM/T-2 sensors. It is essential that the climate time series continue without any artifacts. Finally, there are several calibration issues that need to be resolved in order to promote the current time series into true Climate Data Records (CDR’s); these issues will be discussed in complementary papers at this conference (Weng et al., Bates et al.