Peering Through Clouds: Microwave Radiometry’s Crucial Role in Weather Prediction
Microwave radiometers measure brightness temperature from natural microwave emissions, enabling all-weather, day‑and‑night sensing through clouds, haze, and light rain. Oxygen absorption bands around 60 GHz (with a separate line at 118 GHz) are used for temperature sounding, while water vapor absorbs near 22.235 GHz and 183 GHz for humidity profiling. Nimbus-7 SMMR, launched in 1978, was the first conical-scanning microwave imager with five channels at 6, 10, 18, 21 and 37 GHz. DMSP SSM/I, launched in 1987, carried seven channels from 19 to 85 GHz and provided all-weather ocean winds, rain rates, and snow cover. NOAA’s MSU/AMSU family began with