The Numerical Simulate Examination Of Rainstorm On Liaodong Peninsula

There are kinds of cumulus parameterization schemes (CPSs) in the mesoscale numerical model MM5 can be chosen. Different CPSs and horizontal resolution will produce considerably different influences on the precipitation forecast. The purpose of this paper is to investigate the influences of different parameterization schemes and nesting grid on simulation of LiaoDong Peninsula rainstorm by the trials of four common CPSs and nesting grid on LiaoDong Peninsula rainstorm process. We present a numerical simulation test of a heavy rainstorm process that occurred over the southern LiaoDong Peninsula and the BoHai strait areas at 25th July 2005. By comparing and analyzing the output data of different schemes, the maim results are following:The comparison between the numerical simulative results of dual nesting grid and objective analysis indicates that:1. MM5 model can well reappeared the large scale and mesoscale circumfluence systems of LiaoDong Peninsula heavy rainstorm.2. A coupling of the intense divergence on upper levels and intense convergence on lower levels as well as intensive ascending motion and the cyclonic vorticity column are the dynamic mechanisms for the heavy rainstorm occurrence.3. The southwest airflow on lower levels and the inrush of arid cold air on upper levels play an important rules on the out-growth and development of this rainstorm.The comparison analysis for cumulus convection parameterization scheme No.1 shows:1. Different parameterization schemes have significant difference of the simulative effects on the location of rainfall center and rainfall intensity. The GR scheme was the best, the AK scheme was the worst.2. The simulative sea level pressure of four CPSs showed large difference, in which the GR scheme had better simulated the high, low systems and mesoscale cyclone.3. The coarse-mesh scheme which adopting certain cumulus convection parameterization can reappear some mesoscale characteristics in a certain extent.4. Because of different closure assumptions in four schemes, the simulated cloud physical characteristics have significant difference. This difference will have some effects on the accurate prediction of kinds of weather elements.The comparison analysis for cumulus convection parameterization scheme No.2 shows:1. Fine-mesh messages can be transferred to outer space by nesting border, so that affect the forecast results. Fine-mesh of GR scheme can better simulate than that of AK, BM and KF schemes.2. When fine-mesh parameterization scheme is invariable, different coarse-mesh...