Analysis On The Variation Characteristics And The Influencing Factors Of The Summer Precipitation In Inner Mongolia

The temporal and spatial variability characteristics and Influencing factors of the precipitation in Inner Mongolia had been analyzed based on the monthly precipitation from110stations of Inner Mongolia from1971to2010and NCEP reanalysis data of the geopotential height field, wind field, sea surface temperature by the methods of the linear trend estimation, EOF, REOF, wavelet analysis, correlation analysis, SVD. The spatial distribution of summer precipitation in Inner Mongolia was that the east was much more than the west. Rainfall mainly concentrated in July. There were three main types of precipitation:the overall consistency type, the east-west difference type, the difference between the northeast, the central section, the west section of east and the east section of south, the west section of west type. The summer precipitation had obviously interdecadal variability. The precipitation showed an increasing trend from the early seventy’s to the late ninety’s and decreased quickly from the late ninety’s to2010with the cycle variation of6years and6to9years. The most precipitation was in1998and the least precipitation was in2010. Synthetic analysis of atmospheric general circulation in the troposphere level of positive precipitation and negative anomaly years were used. The results showed that three mostly anomaly regions had different characters of atmospheric general circulation of positive and negative anomaly years, and the same region also had distinctive features. Correlation analysis on the summer precipitation from110stations of Inner Mongolia with the SST in the North Pacific, the South Pacific Ocean, the India ocean, the North Atlantic ocean by SVD. The results showed:the South Pacific Ocean, the North Atlantic ocean had significant influences on the summer precipitation in Inner Mongolia.