Advancing ice-cloud detection from microwave sounding data

CubeSat TROPICS added a J-band channel at 205 GHz to TROPICS Millimeter-wave Sounder (TMS), while conventional Metop-SG satellite added a J-band channel at 229 GHz to its Microwave Sounder (MWS) for detecting small precipitating ice clouds. This study shows that the two J-band channels together can provide sensitivity for detecting non-precipitating and lightly precipitating ice clouds. The weighting functions for the two channels are found to be nearly identical, and their clear-sky brightness temperatures are practically the same within the instrument Noise Equivalent Delta Temperature (NE Δ T). Using a new scattering index, defined as the brightness temperature difference between the two J-band channels, ice clouds are clearly visible in the imagery of the new scattering index.