2019年初浙江罕见连阴雨过程的成因分析  

Cause Analysis of Rarely Continuous Rainy Weather in Zhejiang Province during Early 2019

作　　者：陈光宇[1] 沈杭锋[1] 方陆俊 陶然亭 樊李苗 CHEN Guangyu;SHEN Hangfeng;FANG Lujun;TAO Ranting;FAN Limiao(Hangzhou Meteorology Service,Zhejiang,Hangzhou 310051)

机构地区：[1]浙江省杭州市气象局,杭州310051

出　　处：《气象科技》2023年第4期532-540,共9页Meteorological Science and Technology

基　　金：浙江省气象局预报员专项项目(2021YBY03);浙江省基础公益研究计划(GF21D050002)资助。

摘　　要：利用浙江省2019年2月地面气象观测资料、FY-2G红外云图资料、NCEP和ERA-Interim再分析资料,对浙江省2019年冬末春初典型的连阴雨天气过程的成因进行了分析,得出以下结论:(1)连阴雨期间500 hPa极涡呈偶极型,主体持续收缩在北极附近,浙江位于700 hPa和850 hPa切变南侧稳定的西南气流及温度正距平中,对流层高层西风急流持续偏强、位置偏北,强度和位置变化超前于降雨;(2)源自孟加拉湾北部至青藏高原、中南半岛到南海的两条水汽通道持续输送水汽至我国华东地区,浙江同时受两条水汽带叠加影响时雨强达到最大,红外卫星云图分析可对水汽输送通道和天气形势作大致判断,提供降雨预报辅助性参考;(3)700 hPa湿Q矢量显著辐合区和850 hPa经向风0 m·s^(-1)等风速线重叠的区域易出现明显降雨,集中降雨时段浙江上空存在很大的低层假相当位温和水汽通量的水平梯度,水汽输送带位于梯度区之上。An event of continuous rainy weather occurred in Zhejiang Province in February 2019.The characteristics of atmospheric circulation are analyzed based on conventional observed data,FY2E infrared satellite data,NCEP and ERAInterim reanalysis data.The results show:(1)The polar vortex shrinked near the North Pole in February 2019,which caused positive temperature and southwest wind anomaly at 700 hPa and 850 hPa;the westerly jet on the upper troposphere was norther and stronger than usual.The intensity and location of the jet changed ahead of rainfall.(2)There were two water vapour transport channels during continuous rainy weather,which were from the Tibet Plateau and Bay of Bengal vapour channel,IndoChina Peninsula and northern South China Sea.There will be heavy rain when both water vapour transport channels are strong in Zhejiang Province,and it can be clearly seen from the infrared cloud image.(3)The wet Q-Vector convergence area at 700 hPa overlapped with the 0 m·s^(-1)longitudinal wind area at 850 hPa corresponded well with heavy rain area.There were large pseudoequivalent potential temperatures and watervapour flux horizontal gradient in the lower troposphere,water vapour transport belt was under it.

关 键 词：连阴雨 水汽输送 湿Q矢量散度 假相当位温 

分 类 号：P458[天文地球—大气科学及气象学]