INTERANNUAL VARIABILITY OF THE MEIYU ONSET AND ITS ASSOCIATION WITH NORTH ATLANTIC OSCILLATION AND SSTA OVER NORTH ATLATIC

In the context of simplecor relation and composite analysis,study is performed of the correlation bet ween Meiyu onset dates(MOD) and at mospheric cir culation in the previous winter.Result shows that the MOD is significantly related to the at mospheric features in the previous winter with strong North Atlantic Oscillation (NAO) for early Meiyu onset and v.v..Resul talso indicates that there exists pronounced correlation between the MOD and SST over the North Atlantic in the previous winter-to-spring with positive SST anomalies for early Meiyu onset and negative anomalies for late Meiyu onset,which implies important significance for Meiyu onset prediction.Finally,numerical simulation is taken to investig ate the mechanism of effects on the Meiyu onset and precipitation of the warm sea surface temperature over the North Atlantic.