典型旱涝年环流的旬平均和旬距平特征

利用ＥＣＭＷＦ高度场资料，详细分析了１９８５年和１９９１年５月主要季风环流系统的旬平均和旬距平特征。结果表明，５月名旬，旱涝年的主要季风系统的位置和强度有明显差异。并指出夏季降水的异常，不仅与５月各旬北半球的南亚高压，极涡，西太平洋副高等系统的活动异常有关，而且与南半球的澳大利亚冷高，马斯克林高压的强弱有关，甚至与南半球中高纬环流的经向度大小也有联系。

FEATURES OF DECADAL MEAN AND ANOMALY OF MONSOON CIRCULATIONS IN YEARS OF SEVERE FLOOD/DROUGHT

In the context of ECMWF height data, investigation is conducted of the decadal mean and anomaly characteristics of major summer monsoon systems in May, 1985 (of drought) and 1991 (severe flood). Evidence suggests that the position and vigor of the monsoons greatly differ from decade to decade between the years; summer rainfall anomaly is associated not merely with the anomalous activities of South Asian high, polar vortex and western Pacific subtropical high but with the strength of Australian cold high and Mascarene high, and even with the meridionality of circulations at southern extropics as well.