The Relation of Surface Heating Fields over the Qinghai-Xizang Plateau to the East Asian Circulation and the Early Summer Drought in Northwest of China

Using the earth–atmosphere temperature difference data set of 60 observation stations over the Qinghai–Xizang Plateau for 25 years, the strength of the Plateau surface heating fields is calculated. Maximum load values derived from EOF are selected from Yushu and Rikaze stations, which are used to roughly represent the characteristics of the whole Plateau. Mouthly mean departure indices of surface heating strength for the two stations over the years of 1958—1987 are calculated. According to the indices, the evolution of surface heating field and its relation to the East Asian circulation and Northwest early summer drought are estimated statistically. The conclusion can be used for a long–range weather forecasting of the early summer drought in northwest of China.