A Case Observational Analysis And Numerical Simulation Study Of The Stratiform And Embedded Convective Precipitation Process Over North China

The stratiform and embedded convective cloud is a major precipitation cloud system, and also is a very effective precipitation system over North China. Observations show that, the dynamic and thermodynamic structure and precipitation process of the stratiform and embedded convective cloud have its own unique characteristics. Therefore, research and analysis on the characteristics of radar echo, precipitation mechanism, macro and micro characteristics and the results of numerical simulation of the stratiform and embedded convective cloud in North China, are very helpful to enhance the forecasting level over this area, and also provide theoretical support for weather modification.This paper is used MICAPS satellite cloud image, ground obvervation and high alititude observation data and DaTong ShanXi province Doppler radar station collected survey data, observed and analyzed April30,2009to May1st (Beijing, after the same) occurs in a convergence weather system causing mixed stratiform cloud precipitation data, discussed the convergence of stratocumulus cloud development dynamic, thermodynamic characteristics and micro physical structure characteristics. And then, used the WRF-ARW to simulated a convergence weather systems stratocumulus cloud precipitation, which occurred in the North China the April30,200908to May2nd02, from power, thermal mechanism and cloud microphysical processes of stratiform mixed clouds dynamic, thermodynamic and micro physical structure, as well as seeding-supply mechanism of stratocumulus cloud development function.The observation analysis found that, Saddle shaped field configuration with the warm on cold and vertically unstable structure, is the main reason for the convergence linear stratiform and embedded convective precipitation. The cloud system has obvious radar and precipitation characteristics of product type stratiform and embedded convective cloud. At that time, the whole North China divergence field by ground to altitude show convergence-divergence-convergence-divergence configuration. The precipitation process vapor mainly comes from the lower layer, but the accumulated precipitation is not great, probably the reason is dust and blowing sand weather inhibits the development of convection and reduce the precipitation efficiency of cloud. The simulation results shows that, moisture convergence is mainly caused by warm-moist airflow from southwest, and the atmospheric stratification of warm-moist airflow area keeps in an unsteady state all the time, while the dramatic fluctuations of updraft lead to embedded convective clouds. There cold and warm cloud precipitation mechanism coexists in the precipitation nephsystem, and the main rainfalls are supplied by the convective cloud, and the "seeder-feeder" mechanism may be the main reason of the convective stratiform mixed cloud precipitation.