Abstract : 2G.5
Atmospheric boundary layer circulation on the eastern edge of the Tibetan Plateau in summer

Yueqing Li, Wenliang Gao
yueqingli@163.com
Institute of Plateau Meteorology, China Meteorological Administration, Chengdu

By using radiosonde data in Sichuan Province and Chongqing Municipality of China during May-September from 1982 to 2002, the meteorological significance and evolution regularity of atmospheric boundary layer (ABL) wind at the eastern edge of Tibetan Plateau are analyzed. Results show that the ABL wind at Chengdu near the eastern edge of the Tibetan Plateau varies with regularity. Because the interaction between the circulation and the topography, the wind field exhibits alternately northeast wind with southwest wind. When it is northeast wind in the ABL at Chengdu, the ABL in Sichuan Basin maintains cyclonic flow field, and it will be in corresponding with heavy rain in Sichuan Basin. When it is southwest wind, the ABL maintains anticyclonic flow field, and it will be in corresponding with rainless fine weather in Sichuan Basin. Under the special background of the northeast-southwest trend topography between Tibetan Plateau and Sichuan Basin, the dynamical trigger of the ABL at Chengdu is a very important cause for the occurrence and development of the severe convective weather such as heavy rain in Sichuan Basin. The Chengdu station is the key information point for the weather variation in Sichuan Basin near the eastern edge of Tibetan Plateau and implies major weather information and physical mechanism.