The Variation Characteristics Of Spring Precipitation In Eastern China And Its Relationships With Atmospheric Circulation And SST

Using daily precipitation data of 753 stations in China during 1960-2010 which provided by National Climate Center, NCEP/NCAR reanalysis data, SST data and PDO index supplied by NOAA. The climate characteristics, interannual variation, interdecadal variation and their relationships with atmospheric circulation and SST are studied. The results show that:(1)Distributions of the average precipitation, the variance and the percentage of spring precipitation in annual total rainfall show the distribution characteristics that southeast regions is much more than northwest regions. The spatial distribution of spring precipitation in China has two major forms. The first form is the anti-phase distribution in south and north China. The second form is the middle areas (lower reaches of the Yellow River and North China) has opposite distribution characteristic with north and south China. There two types of spatial distribution of spring precipitation show the interannual and interdecadal variation significantly.(2) On the interannual time scale, the spring precipitation in Eastern China is divided into four types. The atmospheric circulation background and SST field corresponding to each type have different characteristics. On the basis of this condition, confirming the SST key area which effect type I and II precipitation are the central and eastern equatorial Pacific and the Indian Ocean. The significant effect period is early autumn and winter. The SST key area which effect type III and IV precipitation are the central and eastern equatorial Pacific, North Pacific and Western Pacific, the significant effect period is early summer and winter.(3) On the interdecadal time scale, the spatial distribution of spring precipitation in Eastern China experienced four stages of change. Taking Southern China as the key area to study the interdecadal variation characteristics of spring precipitation, it is found that spring precipitation in South China has experienced three stages. Not only the rainy period and the dry period, but also the two dry period have the different circulation background. Furthermore, spring precipitation in South China has positive correlationship with PDO index. In the view of the seasonal changes, there exists the most significant coorelation between the PDO index of previous autumn and spring precipitation in South China on the interdecadal timescale. From the view of different stages of the interdecadal variation of spring precipitation in South China, the positive correlation of PDO index and spring precipitation in South China is the most obvious in the period from 1960 to 1971.