Thermal difference between the Tibetan Plateau and the plain east of Plateau and its influence on rainfall over China in the summer

There exist thermal differences between the Tibetan Plateau (TP) and the plain east of the TP, and between land and sea in East Asia. The influence of the land-sea thermal contrast on the precipitation in East China has been widely investigated; however, a few studies have paid attention to the role of the TP-plain thermal difference. Thus, using the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and the observation data of China from 1951 to 2007, the area-mean temperature difference between the TP (27.5°-40°N, 80°-100°E) and the plain (27.5° -40°N,110°-120°E) at 500 hPa is defined as an index (dexT-C) of the TP-plain thermal difference in East Asia. The relationship between the dexT-C and East Asian general circulation and the rainfall in China in the summer has been explored. Diagnostic analysis and numerical simulation show that the TP-plain thermal difference is closely related to the rainfall over West China (90°-110°E) in the summer. High values of the dexT-C correspond to the large thermal difference between the TP and the plain, strengthening the heat low over the TP, southward of the northwestern Pacific subtropical high, southern flood and northern drought in West China (90°-110°E), and vice versa. From 1951 to 2007, the variation in dexT-C exhibits a remarkable oscillation and ascending trend, and the abnormal rainfall pattern over West China (90°-110°E) also changes from "northern flood and southern drought" to "southern flood and northern drought". The above research is favorable to knowing how the two-stage thermal differences influence summer rainfall in China.

There exist thermal differences between the Tibetan Plateau （TP） and the plain east of the TP, and between land and sea in East Asia. The influence of the land-sea thermal contrast on the precipitation in East China has been widely investigated; however, a few studies have paid attention to the role of the TP-plain thermal difference. Thus, using the National Center for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data and the observation data of China from 1951 to 2007, the area-mean temperature difference between the TP （27.5°-40°N, 80°-100°E） and the plain （27.5°-40°N,110°-120°E） at 500 hPa is defined as an index （dexr_c） of the TP-plain thermal difference in East Asia. The relationship between the deXT-C and East Asian general circulation and the rainfall in China in the summer has been explored. Diagnostic analysis and numerical simulation show that the TP-plain thermal difference is closely related to the rainfall over West China （90°-110°E） in the summer. High values of the dexT-C correspond to the large thermal difference between the TP and the plain, strengthening the heat low over the TP, southward of the northwestern Pacific subtropical high, southern flood and northern drought in West China （90°-110°E）, and vice versa. From 1951 to 2007, the variation in deXT-Cexhibits a remarkable oscillation and ascending trend, and the abnormal rainfall pattern over West China （90°-110°E） also changes from ＂northern flood and southern drought＂ to ＂southern flood and northern drought＂. The above research is favorable to knowing how the two-stage thermal differences influence summer rainfall in China.