2020—2021年沈阳地区4次短时强降水过程的大气可降水量变化对比分析

Comparative analysis of changes in atmospheric precipitable water during four short-time heavy rainfall processes in Shenyang from 2020 to 2021

选取2020—2021年夏季沈阳地区出现的4次短时强降水过程,利用欧洲中心(ECMWF,European Center for Medium-Range Weather Forecasts)ERA5再分析资料、地基GPS(Global Position System)大气可降水量资料和常规观测资料,分析不同天气系统影响下,沈阳地区短时强降水过程中GPS水汽与水汽通量的变化特征。结果表明:短时强降水过程前,水汽累积时间的长短与相应的天气系统关系密切。副热带高压系统外围导致的强降水过程,大气可降水量(Precipitable Water Vapor,PWV)可以一直维持在较高水平,水汽增长速度可达1.1 mm·h^(-1)。此外,强降水出现时段与PWV峰值阶段相对应,但二者峰值并不完全重合;短时强降水出现时,沈阳站的大气可降水量超过38 mm;强降水结束后,PWV明显减弱。

Based on the ECMWF(European Center for Medium-Range Weather Forecasts)ERA5 reanalysis data,GPS(Global Position System)precipitable water vapor observations,and conventional observation data,the variation characteristics of atmospheric PWV(Precipitable Water Vapor)and water vapor flux during four short-time heavy rainfall processes from 2020-2021 under different weather systems in Shenyang were analyzed.The results show that the duration of water vapor accumulation is closely related to the corresponding weather system.PWV can be maintained at a relatively high level in the heavy rainfall process caused by the periphery of the subtropical high system,and the water vapor growth rate can reach 1.1 mm·h^(-1).In addition,the occurrence period of heavy rainfall corresponds with the peak of PWV,but the peaks of the two do not coincide completely.When short-time heavy rainfall occurs,the atmospheric precipitable water at Shenyang station reaches more than 38 mm.After the end of heavy rainfall,PWV weakens obviously.