THE TIME-SPACE VARIETY CHARACTERISTICS OF THE SURFACE TEMPERATURE OVER THE QINGHAI-TIBET PLATEAU

In this paper, the basic climate characteristics of winter, summer and annual mean surface temperatures were analyzed by using 86 stations during period from founding to 2001 over the Tibetan Plateau, and the spatial anomaly structure and time evolution tendency have been analysed systematically through principal component analysis, a periodic function and a random function and power spectral analysis methods. The result shows that the surface temperature is a function of sea level elevation and latitude in the Tibetan Plateau, the higher the elevation and latitudes are, the lower the surface temperature is . The annual highest surface temperature is 14.9 ℃ of Cayu in the Yaluzangbu river, and the highest value of the surface temperature in summer is 23.0 ℃ at Germu in the Chaidamu basin. The souther Talmu basin of the plateau outer circle, the temperature is higher in western Sichuan, but the center is not in the plateau. The Lowest value of surface temperature in the center of the plateau is -0.2 of annual mean surface temperature, winter then much lower (average -14.2～-15.8 ℃). The lowest value of the surface temperature is 9.8 ℃ at Qingshuihe in summer, its average in July is 10.7℃. The first loading vector of the surface temperature over the Plateau is overall consistency. The second loading vector has a difference in the north and the south. The variety of the first principal component has an obvious up-trend in the last 30 years, but the second principal component is a slow-moving descent, and there is a quasi periodic oscillation of 7～9 years for the interannual variation.