Moisture transport source/sink structure of the Meiyu rain belt along the Yangtze River valley

摘要

Based on the analyses of the moisture transport structure in the whole layer of the troposphere along the Yangtze River valley during drought/flood years using the NCEP reanalysis data, this paper reveals that there exists a key region with a "Large Triangle" shape of transporting moisture for the Tibetan Plateau to Meiyu Belt and its "source/sink" structure; discloses that the interannual variation of the whole budget of inflow and outflow of moisture through the boundaries of a "Large Triangle" keyregion has the in-phase characteristic. Then a moisture transport structure over the skirt of the plateau and a conceptual model on the "transfer post" of moisture transport in the area of the South China Sea-Tibetan Plateau-Yangtze River valley in summer are put forward in this paper; the anti-phase feature of whole layer moisture transport flow patterns of Yangtze River valley during drought/flooding years is exhibited using the computational scheme of whole layer moisture transport correlation vector fields; a comprehensive dynamic model and its physical diagram of the tele-connection source/sink structure of the moisture transport of the Meiyu rain belt have been made. It shows that the moisture transfer effect over the skirt of the plateau from the ocean (Indian Ocean, South China Sea and w-est North Pacific) led to a moisture confluence belt in the Yangtze River valley and the teleconnection moisture transport source/sink structure over the "Large Triangle" shape area in flooding years.