Spatial Pattern of Seasonal Precipitation over the Eastern Part of China

Using constructed and observational data of seasonal precipitation in Eastern China(east to 110°E)over 1880-2004,major characters of spatial distribution of precipitation in each season are studied with EOF analysis.Two primary patterns of spatial distribution are found.While precipitation in winter,spring and autumn belong to the first pattern,summer is of the second one.Furthermore,combined with the constructed data of 1880-1950 and observational data of 1951-2004 on 500 hPa geopotential height,the impact of circulation on seasonal precipitation is studied.The results show that the spatial distribution of abnormally seasonal precipitation usually has a close connection with high-level circulations,and the relationship of the two is stable in the past hundred years or more.Finally,research on the periodic variation of spatial structure of seasonal precipitation reflects that every season has interannual and interdecadal variability.The outcome of spectral analysis and wavelets shows that the periods of 2-4 a,5-8 a,15 a,20-25 a and 60 a are the leading cycles of seasonal precipitation in Eastern China.