The Characteristics For Summer Monsoon's North Boundary And Abnormal Vibration's Thermal Mechanism In East Asian

The summer monsoon brings plentiful water vapor, which is important for vegetation's growth, and also for people's subsistence. The relation between monsoon's northward advance and north boundary' location is consanguineous. There are many monsoon's indexs, and also many people have investigated the northward advance of the summer monsoon. Basing the sensitivity of the vegetation for summer monsoon's boundary belt's climatic variety because of which's precarious precipitation. So this research method which from the vegetation growth angles accords with the monsoon's influence more in China. Using data that includes with station data and grid data, just using the daily rainfall data of 715 stations of China from 1951 to 2006 to depict the summer monsoon's advancing process and using NCEP/NCAR monthly mean and daily reanalysis data to investigate moisture transport. Firstly, the soaking rainfall index is defined to confirm the East Asian summer monsoon area. It takes appearing six times and more soaking rainfall (20mm) processes during April to October as the standard, then the boundary belt positions for summer monsoon are defined according to the range of six times soaking rainfall line waving variance annually, and wind vector changed in the boundary belt. At the same time, setting the continual soaking rainfall processes which reach the no-dry standard as the start time of East Asian summer monsoon. This start time can represent the summer monsoon's northward advance.Besides, the characteristics of annual and decade variance of East Asian summer monsoon's north boundary and the variance of boundary belt's scopes are analyzed. Furthermore, analyzes the advanced process of East Asian summer monsoon 's north boundary and its influence to the rainfall of China. For realizing the formation that caused the north boundary of summer monsoon waving unconventionally, it is important to analyse Moisture transport which maybe one important gene. The thermal difference between ocean and continent is a directer reason of the monsoon phenomena. The text discusses the mechanism of abnormal vibration for summer monsoon's North boundary in East-Asian according to the thermal status on both continent and ocean. The results show that: the soaking rainfall standard ascertains boundary blet's location for East Asian summer monsoon preferably, and it appears a tendency of southward moving and the scopes of boundary belt is enlarged. In brief, the location variance of East Asian summer monsoon's north boundary have a close correlation with souther's intensity and moisture transport ,and also have a certain influence to the rainbelt distribution of our country as well as the precipitation in north of China, north boundary inclined north, .also do the rainband, and the rainfall is relatively more in the north of china. The Bay of Bengaland Region of western Pacific Ocean have a low surface air temperature while the summer monsoon's North boundary locate abnormally northern, however, it's not obvious for the difference of the surface sea temperature. The intensity of surface heating fields over the tibetan plateau has a negative correlation with the location of the monsoon's North boundary, the infirm intensity of surface heating fields are propitious to the summer monsoon's North boundary inclining northern.