Soil moisture and TRMM microwave imager relationships in the Southern Great Plains 1999 (SGP99) Experiment

Satellite data collected by the Tropical Rainfall Measuring Mission (TRMM) microwave imager (TNM and the special sensor microwave/imager (SSM/I) were compared to soil moisture observations as part of the Southern Great Plains (SGP) 1999 Experiment. SGP99 was conducted to address significant gaps in the knowledge base on the microwave remote sensing of soil moisture. Satellite, aircraft and ground based data collection were conducted between July 8, 1999 and July 20, 1999, during which an excellent sequence of meteorological conditions occurred. Cross calibration of the SSM/I data to the same TMI channels showed nearly identical brightness temperatures. 19 GHz SSM/I data and soil moisture relationships were similar to those observed in previous experiments in this region. Comparison studies of the SSM/I and TMI channels revealed that only sampling areas with adequate spatial domains should be used for soil moisture validation. Analyses of the TMI 10 GHz data provide new information on potential improvements that this channel can provide for soil moisture estimation. Soil moisture maps of the region were derived for dates of coverage.