Comparative Analysis of the Southwest Vortex Rainstorm Causes at Three Typical Areas in Sichuan Basin

This article is synthetic analysis of the northwest， northeast， southwest type3， which are classified according to fall from more than 2010～2010 typical southwest vortex rainstorm cases，the results show that:（1） the precipitation distribution is closely connected with the terrain in Sichuan basin.（2） the location and intensity of slot or low vortex played a key role to the drop zone.（3） there are obvious wind fields convergence in the basin.Compared with the northeast type and the northeast type，the southwest airflow is very strong in the western part of the basin when the rainfall happens at the northwest/southwest basin， while the big wind speed is located in the eastern part of the basin.（4） the atmospheric water vapor is abundant above the rain belt before the precipitation， and high value zone of water vapor is quite consistent with falling area.（5） the precipitation is closely related to the Stratification stability in the basin，and the most powerful precipitation zones correspond to the most unstable regions of the stratification.