Simulation and Analysis of Heavy Snowfall in the Hexi Corridor with WRF Model

Numerical simulation is made with the new generation numerical model-WRF(Weather Research and Forecast) on a heavy snow process happened in the Hexi Corridor during 13~16 March 2005.It is clear that the WRF model can make good simulation about the snowfall distribution.Main conclusions are as follows:(1) The appropriate collocation of cold front of surface,shear of lower-level wind field and upper-level jet enhances the development of vertical circumfluence.(2) There is the maximum convergent 600 hPa,and the divergent is above 500 hPa when the heavy snowfall is happened.With the beginning of the snowfall,the mesoscale synoptic system fades gradually.(3) There is intense mesoscale ascending motion in the whole snowfall process,and the ascending motion between 500~400 hPa is the strongest.(4) The westerlies(especially 600 hPa) supports enough water vapor to the area of snowfall.