Research On Anomaly Of Summer Rainfall Over Eastern China And The Relationship With Pacific SSTA By Diagnosis Analysis And Numerical Simulations

Using the methods of REOF analysis, the summer precipitation from 43 stations over Eastern China for the periods 1901-2000 was examined. The summer rainfall anomaly over eastern China has three mostly spatial distribution patterns, that is the pattern A, B. C. The anomaly center of pattern A lies South China and Southwest China. The anomaly center of pattern B lies the middle and lower reaches of Yangtze river and Huaihe river reaches. The anomaly center of pattern C lies North China and the Southwestern of Northeast China The interannual and interdecadal variability of threes mostly anomaly regions of the pattern A. B and C were separately analyzed. Synthesize analysis was used to analysis the features of atmospheric general circulation of positive precipitation and negative precipitation anomaly years. The results show that three mostly anomaly regions have different characters of atmospheric general circulation of positive and negative anomaly years, and the same region also has distinctive features, but not complete opposition. On the other hand, the methods of REOF analysis was also used to North Pacific SSTA on spring and summer. The Middle and Eastern Equatorial Pacific and the kuroshio region of Northwestern Pacific are two mostly anomaly regions. Otherwise, by the way of SVD we also analyzed the correlation distribution patterns of the spring and summer North Pacific SSTA and the summer rainfall of 43 stations over Eastern China, and find out there is primely spatial coupling correlation between SSTA and precipitation. Further, correlation analysis is used to the summer rainfall and four seasonal North Pacific SSTA, the results suggest North Pacific SSTA which notability cause the summer rainfall anomaly over Eastern China are prophase winter SSTA of kuroshio region of Northwestern Pacific, prophase spring SSTA of Middle and Eastern Equatorial Pacific and summer SSTA of west wind drift region. Finally, the possible physical mechanism by which the SST of the North Pacific affecting Eastern China summer rainfall was elementary discussed by numerical simulation using model CCM3.