Variability Of Summer Temperature In Northeast China And The Impact Factors

In this paper, with the NCAR/NCEP monthly reanalysis data and the monthly mean temperature in 80 stations in Northeast China between 1961 to 2002, as well as 74 factors of general circulation from Chinese National Climate Center, the feature of summer temperature over northeast China and the correlation between summer temperature and sea-air circulation mechanism are studied by the method of diagnosis and analysis in the climate. The following conclusions are reached:1. The spatial distribution of summer temperature varied consistently over the whole region, with the overall trend of warming in northeast China. The 1960's and 1970s were cold period in the inter decadal variability of summer temperature; then it remained stable in the 1980s; abrupt change of occurred in 1993; in the 1990s, it bounced back..2. Northeast China belongs is located in the south edge of Siberia temperature variation region with the same inter-annual summer temperature variation that east Siberia has.3. The 500hPa westerlies system has profound impact on the summer anomalous temperature in Northeast China .The remarkable features are that in the high-low temperature years, the 500 hPa anomaly high fields are opposite on the middle-high latitudes area as well as the north and south 0 value lines are seated differently in Asia.4. Polar vortex is another important system which affects the variation of summer temperature over northeast of China, the variation of its edge of height field as well as the extent or contraction of the polar vortex in different directions indicates that the flow of polar cold air goes differently, which leads to different distribution and variation of the summer temperature.5. The Pacific Ocean has a persistent impact on the summer temperature over Northeast China. There is remarkable correlation between surface sea temperature (SST) and summer temperature in this region for the concurrent and...