东北夏季降水分型及其大气环流特征

利用1961—2010年中国东北122站逐日降水资料、NCEP/NCAR再分析资料及中国国家气候中心整理的160站月平均温度资料,对东北6月、7月、8月的降水进行分型,在此基础上分析各类降水型对应的环流形势。结果表明:东北6月、7月、8月降水均可划分为两大类四小类,6月与8月的分型结果相同,为全区一致型(同多型、同少型)和南北反位相型(南部型、北部型),7月可分为全区一致型(同多型、同少型)和东西反位相型(东部型、西部型)。6月东北降水主要受东北冷涡影响,冷涡越强,降水越多,且当鄂霍次克海阻塞高压出现明显异常时,6月东北降水将呈现南北反位相特征;7月、8月降水主要受东亚夏季风影响,其中东北降水全区一致型与西太平洋副热带高压的位置以及沿亚洲西风急流东传的波列有关,而降水南北(东西)反位相型则与西太平洋副热带高压的强度有关。

A classification of summer precipitation patterns over Northeast China and their atmospheric circulation characteristics

Based on the daily precipitation data of 122 stations in Northeast China(NEC),the NCEP/NCAR reanalysis data and the monthly temperature data of 160 stations from NCC(National Climate Center) during 1961-2010,this paper reveals the rainfall patterns of NEC in June,July and August and analyzes the characteristics of abnormal atmospheric circulation.Results indicate that the precipitation of NEC can be divided into the consistent rainfall pattern(more rainfall pattern or less rainfall pattern) and the south-north anti-phase rainfall pattern(southern rainfall pattern or northern rainfall pattern) in June and August,and the consistent rainfall pattern(more rainfall pattern or less rainfall pattern) and the east-west anti-phase rainfall pattern(eastern rainfall pattern or western rainfall pattern) in July.In addition,the precipitation of NEC in June is related to Northeast cold vortex(the stronger cold vortex,the more rainfall),and the south-north anti-phase rainfall pattern is affected by the abnormal Okhotsk blocking high.The precipitation of NEC in July and August is related to East Asian summer monsoon,and the consistent rainfall pattern is affected by both the location of western Pacific subtropical high and the the wave train propagating eastward along the upper westerly jet stream,while the south-north(east-west) anti-phase rainfall pattern is affected by the intensity of western Pacific subtropical high.