Rain retrieval using the 183 GHz absorption lines

Abstract

High spatial resolution AMSU opaque channels are used to retrieve rain rates and classify precipitation types. The retrieval scheme (183-WSL) consists of two fast algorithms, one for land and the other for sea surface, that use the water strong lines at 183.31 GHz to infer rain rate amounts based on a series of thresholds calculated to remove the condensed water vapor effect and discriminate between convective and stratiform pixels. The reported results show the sensitivity of the technique to detect deep convective clouds and to measure light-rain stratiform systems. This latter fact recommends its application particularly over mid-latitude basins where persistent light rains cause intense run-off episodes. Other studies are planned to apply the method at high latitudes where the atmospheric humidity is mainly located within the surface layers and appropriate correction coefficients need to be found.