On-orbit microwave blackbody calibration using regions of dense vegetation

Brightness temperatures (TBs) from satellite microwave radiometers need to be calibrated on-orbit at the hottest and coldest ends of the dynamic TB spectrum. A method is developed to determine hot reference calibration TBs from SSM/I TB data for other radiometers operating between 18-40 GHz and 0-55 degrees incidence. Regions of optically thick vegetation in the Amazon rainforest are chosen as calibration targets. Hot reference temperatures for the on-orbit calibration of microwave radiometers are determined for these regions.