Influence of Pacific-Indian Ocean SSTA on Interannual Variation of Summer Precipitation in Shaanxi

Abstract

Based on the Shaanxi summer precipitation data from 1961 to 2008,NOAA monthly sea surface temperature( SST),NCEP / NCAR monthly global reanalysis data,the relationship between early to the same period in different seasons of the Pacific,Indian Ocean and Shaanxi summer precipitation was analyzed using regression method,SVD method and the cross wavelet analysis method in order to provide clues and foundation for Shaanxi climate prediction. The results showthat: The correlation between Shaanxi summer precipitation with central eastern equatorial Pacific and the western Indian Ocean SST in early autumn and winter is positive,and with North Pacific SST is negative. The distribution of SST correlation coefficient is El Nino SST distribution. To the summer over the same year,the significant positive correlation zone move westward to the eastern Indian Ocean and the eastern coastal of China. The significant regions of influence of Pacific-Indian Ocean SSTA on Shaanxi summer precipitation over Preperiod and the same period locate in Guanzhong and the southeast of Shaanxi. The winter Nino3 SST and Shaanxi summer precipitation has the same phase resonance cycle in the 4 ~ 5 years scale and Nino3 SST ahead of the Shaanxi summer precipitation change is about 4 ~ 6 months. The correlations between East Asia,the South China Sea,Southeast Asia summer monsoon index and Shaanxi summer precipitation and Nino3 SST is all negative. When early Nino3 SST is abnormally high,the East Asian summer monsoon weakened,the Western Pacific subtropical high is stronger and more west,it always appears anomalies southwest wind water vapor transport in southern of Shaanxi,and appears anomalies north wind in northern of Shaanxi Province; the confluence of the warm and cold wind flowin Shaanxi cause more summer precipitation in Shaanxi Province,otherwise summer precipitation in Shaanxi less.