Microphysical processes of the “21·7” Henan extremely heavy rainfall event as simulated with the Thompson microphysics scheme

A numerical simulation was performed using the Thompson microphysics scheme to preliminarily investigate the features of the microphysical processes involved in the record-breaking rainfall event that occurred in Henan Province, China, on 20 July 2021. The simulation results showed that a strong meso-γ-scale vortical updraft was concurrent with the torrential rainfall. The main finding is that this event was characterized by typical midlatitude warm-rain processes. The simulation with the Thompson microphysics scheme further indicated that highly efficient collision–coalescence of cloud water to rainwater resulted in a considerably active rain droplet growth, leading to this record-breaking rainfall event.

摘要

对2021年7月20日发生在河南郑州的一次极端降水事件进行了数值模拟. 模拟结果显示强烈的中-γ尺度旋转上升运动与极端降水同时出现. 研究进一步指出该极端降水事件表现为典型的中纬度暖雨降水过程, 基于Thompson方案的水凝物粒子混合比收支诊断结果表明这次极端降水事件主要由高效的碰并增长过程导致.