A Comparative Analysis on the Cause of Two Heavy Rainfalls Southern Shaanxi

By diagnostic analysis,a comparative analysis is made on circulation background,primary influence system,vertical circulation and thermodynamic characteristics of two small-scale heavy rainstorms on June 8,2002 in Fuping and August 8,2003 in Ningshan in the south piedmont of Qinling mountain in Shaanxi.It is pointed out that the couplings between lower tropospheric jet and upper jet and instable stratification of atmosphere in lower level in troposphere play main roles in two heavy rainfalls under comparatively stable circulation situation.