Diagnostic study on vertical structure of tropical precipitating cloud systems using lower atmospheric wind profiler

Abstract

Temporal variations of vertical structure of precipitating clouds in tropical India have been studied based on the observations of 1.357 GHz lower atmospheric wind profiler (LAWP) at Gadanki. In the presence of precipitating clouds, backscattering from hydrometeors is dominant and the vertically pointing LAWP measures the backscattered energy and the

vertical velocities of the hydrometeors directly overhead. These observations yield time-altitude cross-sections of equivalent reflectivity, Doppler velocity and spectral width that illustrate the evolution of precipitating cloud systems. The vertical structure of these three parameters has been used to classify the precipitating cloud systems into three types: convective, transition and stratiform. Diurnal and seasonal variations of the occurrence of precipitating cloud systems show that the precipitation primarily occurs in the afternoon and also the convective and transition clouds are most frequent in the south west monsoon, while the occurrence of stratiform clouds is predominant in the north-east monsoon. Gadanki-LA WP provides means for the development of climatology of tropical precipitating cloud systems. Such climatology is needed to specify diabatic heating rates in large-scale numerical weather prediction and climate models.