Mei-yu, Arctic Oscillation and stratospheric circulation anomalies
梅雨与北极涛动及平流层环流异常的关联

How about the influence of stratospheric process on the climate as a scientific problem has been paid more attentions in the world.So that there is a special subproject-SPARC in the WCRP.Based on the data analyses,it is shown in this paper that mei-yu precipitation may be influenced by the stratospheric atmosphere circulation anomaly through the Arctic Oscillation(AO) in the troposphere.The stratospheric atmosphere circulation in February is closely related to the AO in March.It may affect the AO through the downward propagating wave activity anomalies.The EOF1st and EOF3rd leading modes of 30hPa geopotential height in February are significantly associated with anomalous downward E-P flux in the subtropics and the polar region,respectively.The AO in March may in turn exert an influence on summertime circulation in East Asia,which is closely related to the summertime thermal condition of the tropospheric atmosphere over East Asia.The changes of thermal condition and the circulation over East Asia can then lead to anomalous convergence/divergence in Yangtze River Valley,and the anomaly of mei-yu precipitation.