Images of precipitation signatures from DMSP SSM/T-2, SSM/I, and OLS

Abstract The Special Sensor Microwave Water Vapor Sounder (SSM/T-2) is a five-channel passive microwave instrument aboard recently launched spacecraft of the Defense Meteorological Satellite Program (DMSP). Rather than address the primary purpose of the SSM/T-2, which is to retrieve atmospheric moisture, this paper examines its ability to sense precipitation as shown by images of a frontal system off the west coast of the United States. Images from the three SSM/T-2 183-GHz channels depict large regions of upper-level water vapor as evidenced by depressed brightness temperatures. Within the moist regions, even lower brightness temperatures at 183 GHz mark embedded precipitation due to volume scattering by precipitation-sized ice particles. Images of the SSM/T-2 channels at 150 and 92 GHz show ice-phase precipitation marked by low brightness temperatures and, over the ocean, low-level clouds and water vapor, both marked by warming with respect to the radiometrically cold background. This paper compares ima...