两类江淮大水的大气环流特征

文中研究了江淮流域特大洪涝的环流特征。江淮流域洪涝年全国降水有两类分布型:即江淮流域大水年中国降水偏多型和江淮流域大水其南北降水偏少型。研究了这两类降水分布型的环流特征,结果指出:北半球500 hPa位势高度场有着显著的差异。东亚大西洋相关链的建立(南海高压、梅雨槽和鄂霍茨克海高压)是江淮流域多雨的重要条件,而欧洲阻塞高压的建立在全国降水分布型中起着重要的作用。进而研究了东亚大西洋相关链与北太平洋海温的关系。

CHARACTERISTICS OF TWO GENERAL CIRCULATION PATTERNS DURING FLOODS OVER THE CHANGJIANG-HUAIHE RIVER VALLEY

Characteristics of the atmospheric general circulation during the catastrophic floods over the Changjiang-Huaihe River Valley(CHRV) are investigated.There are two precipitation patterns over China in the CHRV flood years: the CHRV floodwhole country-wet(P1) pattern and the CHRV flood-south(north) side-dry(P2) pattern.The circulation analysis results show that there are obviously differences between the NH 500 hPa geopotential height fields of P1 and P2 precipitation pattern.The establishment of East Asia-Atlantic(EAA) correlation chain(the South China Sea(SCS) high-the Meiyu trough-the Okhotsk Sea high over East Asia) is a critical condition for excessive summer precipitation over the CHRV,while the Europan blocking high plays an important role in determining the precipitation pattern over China in the CHRV flood years.Besides,the relation between the EAA correlation chain and the sea surface temperature anomaly(SSTA) in the North Pacific is also studied.