Decadal seasonal characteristics of precipitation microphysics over the Western Ghats using the space-borne precipitation radar

Abstract

Global Precipitation Measurement satellite equipped with space-borne dual-frequency precipitation radar (GPM-DPR) allows to investigate the precipitating cloud microphysics and precipitation structures, irrespective of the terrain's ruggedness. Ten years (from March 2014 to December 2023) of continuous GPM-DPR level2 V07A data is processed to understand the decadal changes in precipitation microphysics across the Western Ghats (8°N-20°N and 73°E-77°E) during the monsoon season including before onset (pre-monsoon) and withdrawal (post-monsoon) periods. The spatial distribution of rain rate (R: mm/h), mass-weighted mean diameter (Dm: mm), and normalized intercept parameters (Nw: m−3 mm−1) shows considerable variations depending on cloud types and seasons. During the stratiform precipitation, low-intensity rainfall dominates, characterized by low Dm and high Nw, indicating a significant concentration of smaller raindrops. In contrast, the escalation of high-intensity rainfall due to increased convective activity and strong updrafts during the convective precipitation causes the enlargement of raindrops, augments the concentration of bigger raindrops. Dm-Nw joint histogram displayed distinguishable patterns; range and peak varied with the cloud type and season. It may result from differences in the occurrence rate of various microphysical processes. The share of collision-coalescences process is a maximum of 72.35 % for the convective precipitation in the monsoon season. At the same time, the highest break-up process contribution is 52.05 % during stratiform rainfall of the post-monsoon season.