2019年浙江省秋旱大气环流特征分析  

Analysis of Atmospheric Circulation Characteristics Associated with Autumn Drought over Zhejiang Province in 2019

作　　者：王健疆 马浩[2] 余丽萍 龚理卿 汪晨 WANG Jianjiang;MA Hao;YU Liping;GONG Liqing;WANG Chen(Quzhou Meteorological Bureau of Zhejiang Province,Quzhou 324000,Zhejiang,China;Zhejiang Provincial Climate Center,Hangzhou 310000,China)

机构地区：[1]浙江省衢州市气象局,浙江衢州324000 [2]浙江省气候中心,浙江杭州310000

出　　处：《干旱气象》2021年第1期1-7,共7页Journal of Arid Meteorology

基　　金：浙江省基础公益研究计划项目“全球变暖背景下浙江省极端旱涝事件早期预警技术研究”(LGF19D050001)资助。

摘　　要：2019年秋季浙江出现全省性旱情,浙中西地区旱情最为明显,多地降水量破历史最低纪录,气温则较常年偏高1.5℃以上,基于浙江省67站降水、气温及综合气象干旱指数资料和NCEP再分析资料,分析2019年浙江秋旱成因。结果表明:降水持续偏少、气温持续偏高是秋旱发生的直接原因。500 hPa极涡主体偏于西半球,亚洲区冷空气强度偏弱,东亚大槽位置偏东、偏北,使秋季影响浙江的冷空气偏弱;西太平洋副热带高压(简称“西太副高”)强度偏强、面积偏大、脊线偏北、西伸脊点位置异常偏西,秋季亚洲南部存在异常高压环流,浙江上空下沉气流明显增强,Hadley环流上升支南北向范围减小及其上升支区域缩小造成的水汽向北输送减弱,中低层水汽较常年辐散更明显等因素是2019年浙江秋旱发生的重要原因。A provincial drought situation occurred in autumn 2019 in Zhejiang,especially in the central and western part of Zhejiang Province.Precipitation in autumn 2019 broke the least record in history,and the temperature anomaly was 1.5℃at most of stations.Based on observation data of precipitation and temperature from 67 normal stations in Zhejiang Province and the NCEP-NCAR reanalysis data,the drought causes over Zhejiang Province in 2019 were analyzed systemically.Such severe autumn drought was directly caused by continuous less precipitation and high temperature.The main part of the polar vortex on 500 hPa was located in the Western Hemisphere,thus cold air intensity over Asia was relatively weak,furthermore,the East Asia trough position was eastward and northward,which was hard to cause the cold air to affect Zhejiang.The more intensive of western Pacific subtropical high(WPSH)and associated northward location of the ridge line and westward advance of the westward ridge point,the abnormal high pressure over South Asia,distinct downdraft over Zhejiang,the narrower-span and slower updraft of Hadley Cell and subsequent weaker northward transport of weaker vapor,stronger moisture divergence in the mid-lower troposphere worked together to bring about the typical drought climate in Zhejiang in autumn 2019.

关 键 词：干旱 大气环流 副热带高压 成因 

分 类 号：P426.616[天文地球—大气科学及气象学]