湖南夏季降水与前期北太平洋海温异常的关系  

Relations Between the Preceding SSTA in Northern Pacific Ocean and Summer Precipitation in Hunan

作　　者：谢傲 罗伯良[1,2] Xie Ao;Luo Boliang(Hunan Institute of Meteorological Sciences,Changsha 410118,China;Key Laboratory of Preventing and Reducing Meteorological Disaster of Hunan Province,Changsha 410118,China)

机构地区：[1]湖南省气象科学研究所,长沙410118 [2]气象防灾减灾湖南省重点实验室,长沙410118

出　　处：《气象与环境科学》2020年第4期49-57,共9页Meteorological and Environmental Sciences

基　　金：湖南省自然科学基金项目(2019JJ50318、2017JJ3170);中国气象局武汉暴雨研究所2018基本科研业务项目(IHRKYYW201804);中国气象局省所科技创新发展专项(SSCX201914)。

摘　　要：利用1979-2018年ERA Interim全球逐月平均海表温度再分析资料和湖南夏季(68月)月降水资料,计算了前期夏季、秋季和冬季北太平洋海温与次年湖南夏季降水的相关场,并分析了前期夏季北太平洋海温影响湖南夏季降水的关键海区。对关键海区海温异常年份次年位势高度、垂直速度、风场、地面气压进行合成,分析前期关键海区海温异常对次年湖南夏季大气环流和降水的影响。结果表明:日本岛与夏威夷群岛之间的海域(关键海区A)和从北美洲西部沿岸向西南延伸至赤道的海域(关键海区B)海温是影响次年湖南夏季降水的关键海区。关键海区A夏季海温正(负)异常年次年,湖南夏季降水整体偏少(偏多);关键海区B夏季海温正(负)异常年次年,湖南夏季降水整体偏多(偏少)。前期关键海区A和关键海区B海温影响次年湖南夏季降水的途径各异:关键海区A海温异常通过引起贝加尔湖南侧环流异常来影响湖南夏季降水;关键海区B海温异常可引起沃克环流异常,从而影响西太平洋副高的强度和位置,导致湖南夏季降水异常。Based on the monthly precipitation data of summer(JuneAugust)in Hunan province and the ERA Interim global monthly mean sea surface temperature(SST)reanalysis data during 1979-2018,the correlation fields between the SST in summer,autumn and winter in the North Pacific and the summer precipitation in Hunan in the next year are calculated and analyzed.Besides,the key sea areas of the North Pacific SST in summer affecting summer precipitation in Hunan are identified.By using composite analysis of geopotential height,vertical velocity,wind and surface pressure,the influence of SSTA in key sea areas on the summer atmospheric circulation and precipitation in Hunan in the following year are also discussed.The results suggest that the sea area between Japan Island and Hawaii Islands(the key area A)and the sea area extending from the western coast of North America to the equator(key area B)are the critical areas affecting summer precipitation in Hunan.In the positive(negative)SST year of key area A,the summer precipitation of the next year in Hunan is less(more),and in the positive(negative)SST year of key area B,the summer precipitation of the next year in Hunan is more(less).There are some differences between the ways of key area A and the key area B affecting the summer precipitation in Hunan.The sea temperature anomaly in the key area A can affect the summer precipitation in Hunan by causing the circulation anomaly on the south side of Lake Baikal,while in the key area B,the sea temperature anomaly can cause the Walker circulation anomaly,which affects the strength and location of the western Pacific subtropical high,leading to anomalous precipitation in Hunan.

关 键 词：北太平洋 海温异常 湖南 夏季降水 

分 类 号：P456.3[天文地球—大气科学及气象学]