How Do the Convective and Microphysical Characteristics of Extreme Precipitation Over the Pearl River Delta at Monsoon Coast Vary With Increasing Rainfall Extremity?

Abstract

Using 5-year dual-polarization radar observations, variations of convective and microphysical characteristics of extreme precipitation features (EPFs) with increasing rainfall extremity over a monsoon coastal region (Pearl River Delta; PRD) in South China are investigated through comparing three groups of EPFs (ER1, ER2, and ER3). The more extreme rainfall shows a notable increase and decrease in the fractions of “intense” convection and “weak” convection, respectively. The higher rainfall extremity is accompanied by statistically significant increases in ice and liquid water contents but a roughly equal fraction of coalescence in liquid-phase processes. While the raindrop size distributions of ER1 to ER3 similarly feature a mean size larger than “maritime-like” droplets and a concentration much higher than “continental-like” raindrops, the mean size and concentration of raindrops tend to increase slightly with the increasing rainfall extremity. Two sensitivity experiments on EFP definition confirm the robustness and representative of the above results.