Three-way inter-satellite radiometric calibration between GMI, TMI and WindSat

Satellite precipitation measurements began a new era with the commissioning of the new Global Precipitation Measurements Microwave Imager (GMI) in March 2014. For the previous 17 years, the Tropical Rainfall Measurements Mission (TRMM) Microwave Imager (TMI), operating in a non-sun-synchronous orbit, served as the radiometric transfer standard for the constellation radiometers. Previously, the Central Florida Remote Sensing Lab has conducted independent inter-comparisons over oceans between TRMM Microwave Imager (TMI) and the Naval Research Lab's WindSat polarimetric radiometer, and found that the radiometric calibration of TMI relative to WindSat exhibited exceptional long-term radiometric stability over > 5 years. This paper presents results of the three-way inter-calibration of GMI, TMI and WindSat brightness temperatures during the GPM/TRMM/WindSat overlap period March 2014 – March 2015.