REGIONAL CHARACTERISTICS OF SUMMER PRECIPITATION ANOMALIES OVER CHINA IDENTIFIED IN A SPATIAL UNIFORM NETWORK

The regional characteristic of precipitation anomalies of total summer precipitation (total precipitation of Jule July and Aug.) and monthly precipitation are analyzed by using the results of Varimax EOF and correlation analysis. The data set used is the grid point precipitation over a (5°lat× 5°lon) network in China in the period of 1954 to 1994. The analysis of total precipitation shows that the most significant regional characteristic is the existence of negative correlation in precipitation anomalies between the low-reaches of Yangtse River and the Huaihe River valley (LRYH region) and the middle-reaches of the Yollow River valley (MRY region),and between the LRYH region and South China. The precipitation anomaly over the Sichuan Basin is negatively correlated with that over eastern part of Qinghai Xizang Plateau and that over the LRYH region. The regional characteristics of summer precipitation anomalies in the western China is that there exists negative correlation between the summer precipitation anomalies over the sourthern part of the central and eastern Qinghai Xizang Plateau and that over its northern part. There also exists positive correlation between the sourthern part of eastern Qinghai Xizang Plateau and the eastern part of North China and the southern part of Northeast China. The above spatial correlation modes have significant periods of about 3 years and 10 years. The analyses of the monthly precipitation show that,in Jule,there exists positive correlation among the precipitation anomalies over the LRYH region,the eastern part of North China and the Northeast China. In July,the precipitation in the MRY region and the LRYH regions are negatively correlated. The regional characteristicss of precipitation anomalies in Aug. is very similar to that of the total summer precipitation anomalies.