An investigation of heat source effect of Tibetan Plateau on the wintertime India-Burma Trough

Abstract

In this study, the heat source effect of the Tibetan Plateau (TP) on the India-Burma Trough (IBT) is investigated with multi-layer soil temperatures. Because the significantly positive correlation between the soil temperatures at 10 cm ( T soil −10 ) and the India-Burma Trough intensity index ( IBTI ) lasts from October to the following February, the T soil −10 of TP is selected as the heat source index (HSI). Our composite analysis showed that, when the HSI of TP in the cold season decreases, the subtropical jet moves downward. As a result, the south branch of the westerlies on the south side of the TP is enhanced and the IBT deepens. The upward motion in front of the trough is enhanced, resulting in convergence of a large amount of moisture and a steady vapor transport to Southwest and South China. Conversely, when the HSI strengthens, the subtropical jet moves upwards and the IBT weakens. Meanwhile, the northern branch of the westerlies intensifies, suppressing the moisture convergence and transportation in front of IBT. • The relationship between heat source index (HSI) of TP and India-Burma Trough (IBT) in cold season is investigated. • As HSI decreases, the IBT tends to be intensified due to the subtropical jet moving downward and southern branch of the westerlies strengthening. • Weak HSI in cold season can generally result in sufficient water vapor transportation and more precipitation over south and southwest China.