Numerical Simulation on Stratification and Surface Features of Freezing Rain and Snow Storm over Southern China in January 2008

The PSU/NCAR MM5 model is utilized to simulate the severe freezing rain and snow storm during 26-29 January 2008.And then,the simulation results is used to diagnose the moisture flux,surface temperature,stratification conditions for freezing rain occurrence.The results are that,the numerical model could reproduce the distribution of precipitation band during 26 to 29 January 2008.The east-west oriented quasi-stationary front located along Yangtze River Basin is favorable for the transportation and convergence of water flux.The strongest moisture convergence occurrs ahead the front at low-level and then climbs slantly along the front to middle troposphere.The lifting height and width of moist flux along front surface is consistent with the observed,but the intensity is slightly weaker than the latter.The model also reproduces the stratification and surface features,including inversion layer,warm layer,0 ℃ isoline in surface ground temperature field.It is suggested that the freezing rain area could be predicted by composite consideration of stratification,surface condition and precipitation.