Evaluation of special sensor microwave Imager/Sounder (SSMIS) environmental data records

The Special Sensor Microwave Imager/Sounder (SSMIS) aboard the Defense Meteorological Satellite Program F-16 satellite measures the Earth-emitted radiation at frequencies from 19 to 183 GHz. Compared with the Special Sensor Microwave/Imager (SSM/I), SSMIS has similar imaging channels except for two at 85.5 GHz replaced by the 91.655-GHz frequency. After the Naval Research Laboratory calibration of SSMIS imager channels, the temperature data record can be utilized operationally to derive both atmospheric and surface parameters. In this paper, several products are developed from the SSM/I heritage algorithms, including total precipitable water (TPW), cloud liquid water path (LWP), snow cover, sea ice cover, rain rate, and land surface temperature (LST). Some new products are also derived from the SSMIS, such as land emissivity. The retrieved products from F-15 SSM/I and F-16 SSMIS are intercompared to quantify the mean bias and standard deviation. It is found that because of both the relatively small mean bias and standard deviation, the F-16 SSMIS products, such as TPW, cloud LWP, snow, and sea ice, may replace the SSM/I products for operational use. However, discrepancies remain in the global rainfall estimates, LST, and land emissivity produced by each sensor. This is likely due to the imperfect F-16 SSM/I-like channels to F-15 SSMA channels' linear mapping, particularly for 91.655-GHz channels, whose frequency is shifted from 85.5 GHz in SSM/I.