ABSTRACT

The relationship between atmospheric precipitation and water vapor sources is close, so it is of great significance to carry out the identification of interaction region influenced by different summer monsoons of China. Based on the wind direction data of the Global Data Assimilation System, provided by the National Centers for Environmental Prediction, this study introduces the backward trajectory model of the Hybrid-Single Particle Lagrangian Integrated Trajectory to track the source of rainy season precipitation in Southwest China. It not only quantifies the contribution rate of each geography direction in 16 sampling sites, but also simulates the water vapor transport path and tries to demarcate boundary between the moistures from the Bay of Bengal and the South China Sea. There are three main results. Firstly, the Bay of Bengal, the South China Sea, and the Northwestern Pacific Ocean are the water vapor sources. Secondly, the Bay of Bengal is the most in Yunnan while the South China Sea in Guangxi. Thirdly, the dividing region of different vapors in the rainy season is supposed to be in the eastern of Yunnan, which is nearby three sampling sites, Gejiu, Mengzi and Yanshan. The barrier function of Ailaoshan Mountain should be the major cause.