Interannual And Interdecadal Varieties Of Summer Rain-belt's Propagation And Corresponding Characters Of Height And Sea Temperature

Using daily precipitation data of 355 stations over eastern China and sea temperature &. height field data offered by NCEP/NCAR, and many methods such as EEOF, REOF, Mexico wavelet analysis, synthesized analysis, move-t test, this paper studied the interannual and interdecedal of varieties of summer rain belt's movement and seasonal precipitation change of each area .further analysed the correlations between the two former and corresponding characters of height and Sea temperature. Primary conclusions as follows:Firstly, Summer rain belt is divided into two centers by 110°E line, and their inconsistent propagation speed lead to rain belts propagation to north by way that from northeast to southwest. Rain belts propagation has interdecedal and interannual change. During the strong propagation year, the positive anomaly of precipitation would appear in the north of China, always corresponding I rainfall Pattern, during the weak propagation years, the rain belt appear in south of China, corresponding II or III rainfall Pattern. Further the intensity of their movement have two obvious breaks in 1966 and 1979,so rain band propagate strong during 1957-1966,but weak during 1979-1989.Secondly, eastern China is divided into four areas based on seasonal evolvement characters of Summer rainfall over eastern China and the character of summer rain belt's propagation. And The intension of rain belt's movement has positive correlation with precipitation of South China, Changjiang river valley and areas north to yellow river in Summer, but has negative correlation with Huanghuai area. In the interannual variety it has only obvious positive correlation with the rainfall of north area of yellow river, but in interdecadal variety scale it has obvious positive correlation with the rainfall over South China and north areas to yellow river and has obvious negative correlation with the rainfall of Huanghuai area. The correlation is more obvious in interannual variety scale than in interdecadal variety scale.Thirdly, In interannual scale, the intensity of rain belt's movement have marked positive correlation with SST at middle pacific in the low latitude and northease pacific area in middle latitude and obvious negative correlation with SST of west pacific in the last summer and lastAutumn. The positive correlation with east Pacific around equator during from the last summer to last winter change to negative correlation in the summer. The correlation between sea temperature and the intensity of rain belt's movement is better in interdecedal scale than in interannual scale. Only difference is that 140° w divide east Pacific into positive (west to 140° w) and negative (east to 140° w) parts form last Summer to last Winter. The SST of east Pacific around equator is anomaly worm (cold) from summer to winter in the last year when summer rain belt propagation is strong (weak).But in the same year SST in that areas is anomaly cold(warn),that show the correlation between the intensity of rain belt'movement and SST of east Pacific around equator has two years change period. When SST of east Pacific is anomaly warm (cold) ,Summer rain belt propagates strongly (weakly) next summer, it often happens I or EH (II or III) rain pattern.Fourthly, the weak year of rain belt'propagation, west Pacific High is morn north than orderly years in starting summer ,but morn south in matured summer. In the strong year of rain belt'propagation, west Pacific High is morn south than orderly years in starting summer but morn north in matured summer. In whole Summer, there is negative (positive) height anomaly over middle and low latitude,, so rain belt propagates more north (south).