The Study of a Kind of Circulations Characters on Sustaining Heavy Rain in Sichuan Basin

Using NCEP 1°×1°re-analysis data to analyze a kind of circulations character on sustaining heavy rain in Si-chuan basin.The result showed:First, the atmosphere circulations of heavy rain displayed that there was an western pacificsubtropical anticyclone high, tropic low vortex and short through in 500 hPa, and the transportation path of water vapor wassoutheast wind path, which caused by atmosphere circulations with pacific subtropical anticyclone high and tropic low vortexmainly.Second, variations of local Vorticity were essential for development of large scale atmosphere circulations, and varia-tions of local Vorticity were plus in through region and tropic lowvortexregions, but were negative in region of pacific subtropi-cal anticyclone high mainly.In 850hPa, the increment of local Vorticity had relations to plus local Vorticity transportation oftropic lowvortex regions in heavy rain region, to some extent, the physics process of increment was achieved by plus advectionof Vorticity.Third, the range and center of heavy rain was coincident with the range and center of the range and center of localVorticity, therefore, the variations of local plus Vorticity is a useful physic factor to forecast range of heavy rain.