Analysis On The Variation Characteristics And The Influencing Factors Of The Precipitation In Northern China

The variation characteristics and the Influencing factors of the precipitation inNorthern China have been analyzed based on the Pacific,the Indian sea surfacetemperature (SST) monthly mean data and the precipitation from 244 observationalstations of Northeast China for the period 1960 to 2004. Results show that the annualprecipitation in Northwest area is the smallest one and the precipitation in thenorthwest,the southeast and the northeast of the Northwest area increasesgradually.The annual precipitation is the greatest in the southeast of the Shanxi andLiaoning province.The spatial distribution of the seasonal precipitation basically issame to the annual distribution.. The precipitation in west is small and theprecipitation in east is great.The change of the annual precipitaton is not great andthe linear growth rate is -0.5mm per year.There is not change in the precipitation inspring and the precipitation in winter increases and the linear growth rate is 0.08mmper year.The precipitation in summer and autumn decreases duiring the forty-fiveyears. By Mann-Kendall method the abrupt change is detected in 1972 inwinter.Except the autumm the positive load of the first eigenvector cover the mostareas of the Northern China and the distribution of the second eigenvector is positiveor negative.There is a good consistency of the precipitation in the eastnortharea.The distribution positive load of the third eigenvector of the annual andseasonal precipitation in Northern China is greater than the negative.Except theautumm the negative load takes up all the eastnorth area.By using the REOF methodthe Northern China can be divided into five regions:the middle-east NorthChina,Northeast China,Northern Xinjiang,Northeast Qinhai Xizang Plateau andSouthern Xinjiang,Gansu Corridor,northwest Neimenggu. The North Pacific Oceanand the Indian Ocean have several key regions which affect the precipitation of theNorthern China.