浙江一次强雨雪过程大气环流特征及成因分析  

Atmospheric circulation characteristics and mechanism of a heavy rain and snow process in Zhejiang region

作　　者：许金萍 刘琨 李云[1] XU Jinping;LIU Kun;LI Yun(Anji County Meteorological Bureau of Zhejiang Province,Anji 313300,Zhejiang,China;Shenzhen Municipality Meteorological Bureau of Guangdong Province,Shenzhen 518040,Guangdong,China)

机构地区：[1]浙江省安吉县气象局,浙江安吉313300 [2]广东省深圳市气象局,广东深圳518040

出　　处：《干旱气象》2022年第5期857-867,共11页Journal of Arid Meteorology

基　　金：国家重点研发计划资助项目(2019YFB2102003);浙江省气象局2021年度科技计划项目(2021YB22);湖州市科技局2018公益性技术研究项目(2018GZ32)共同资助。

摘　　要：利用1981年1月至2018年3月浙江省75个国家级气象观测站降水、雪深、气温资料,NCEP/DOE(the National Centers for Environmental Prediction/Department of Energy,NCEP/DOE)逐日再分析资料、及MJO(Madden-Julian Oscillation)指数等对2018年1月下旬浙江地区一次雨雪冰冻过程特征及其可能的影响机制进行分析。结果表明:(1)2018年1月24—28日浙江出现大范围连续雨雪天气,全省平均累计降水量36.2 mm,最大积雪深度平原10~20 cm,山区20~35 cm。雨雪冰冻期间湖州平均气温均低于0℃,较历史同期偏低4℃左右。(2)降雪期间贝加尔湖附近槽东移南下,低纬南支槽东移北抬,冷暖气流交汇于浙江上空,水汽辐合强烈,导致强降雪天气的产生。(3)强MJO事件向东发展,海洋性大陆区域海表气温升高,加强局地经向环流的同时促使暖湿气流西伸北抬,为雨雪天气的形成提供动力及水汽条件。(4)源自北大西洋的Rossby波能量与源自低纬孟加拉湾-中国南海附近的经向Rossby波能量共同堆积于东亚地区,促使负东亚太平洋(East Asia-Pacific,EAP)遥相关型维持、发展,是造成浙江地区连续降雪(雨)的重要原因。Based on the precipitation,snow cover depth and temperature data from 75 stations in Zhejiang Province,the National Centers for Environmental Prediction/Department of Energy(NCEP/DOE) daily reanalysis data,and Madden-Julian Oscillation(MJO) index,the general characteristics and influence mechanism of a freezing rain and snow process occurred in Zhejiang Province during 24–28 January of 2018 has been investigated.The results are as follows:(1) From January 24 to 28,2018,continuous rain and snow weather occurred in Zhejiang,with 36.2 mm accumulated precipitation averaged over the whole areas.During the freezing rain and snow period,the maximum snow cover depth in plain and plateau ranged from 10 to 20 cm and from 20 to 35 cm,respectively,and the average temperature in Huzhou was below 0 ℃,about 4 ℃ lower than the historical.(2) During the snowfall,the trough near the Lake Baikal at high latitudes moved eastward and southward,while the southern branch trough at low latitudes moved eastward and northward.Cold and warm air flows converged over Zhejiang,and the water vapor convergence was strong,leading to the occurrence of heavy snowfall.(3) The strong MJO event developed eastward,and the sea surface temperature(SST) over the maritime continent increased,which strengthened the local meridional circulation and promoted the warm and wet air to extend westward and northward,providing power and moisture conditions for the formation of rain and snow weather.(4) Rossby wave energy from the North Atlantic and the low latitude Bay of Bengal-South China Sea accumulating in East Asia,promoted the maintenance and development of negative East AsiaPacific(EAP) teleconnection,and was an important reason for continuous snow(rainfall) in Zhejiang Province.

关 键 词：浙江地区 雨雪冰冻 MJO 遥相关型 Rossby波作用通量 

分 类 号：P434[天文地球—大气科学及气象学]