Extended Abstract

(a)observed rainfall,(b)simulated rainfall(test 1),(c)simulated rainfall(test 2),(d)simulatedrainfall(test 3),(e)simulated rainfall(test 4)Figure 2 gives observed precipitation and test 1-4 simulated 24-48 hour precipitation chart. Itshows that the precipitation area of east part of Hubei Province can be simulated by test 1-4, butthe rain belt simulated by test 1(no PBL parameterization) moves east quickly, the distribution ofthe precipitation area simulated by MRF scheme is closest to observed data. To the northeast ofHubei Province, the false precipitation simulated by test are most, the precipitation simulated byMYJ scheme is closest to observed data , the precipitation simulated by test 2-4 are all betterthan test 1. To the northwest of Hubei Province, the test 1 Failed to report the precipitation, theprecipitation simulated by MRF scheme is closest to observed data, next is the YSU scheme.Overall, in this precipitation process, the precipitation simulated by MRF scheme is the best andthat of the test 1 is the worst.The simulation was basically possessed of a capability to reproduce the genesis,development and evolution of the large-scale and meso-scale weather systems. Specialanalysis is made to see the impact of different boundary layer parameterization schemes onsome factors which affect the heavy rainfall such as vertical velocity, divergence, vorticity,divergence of water vapor flux,sefield and so on. The simulated results revealed that theprecipitation simulated by the model is sensitive to the boundary layer parameterizationscheme. Different parameterization schemes have different influences on the maximumintensity of rainfall and the distribution of rain area. Suitable boundary layer parameterizationscheme has obvious improvement on simulated results.Key words: GRAPES, PBL parameterizationNumerical Simulation,RainstormReference[1]Garrett, J .R . Sensitivity of climate simulations to land-surface and atmospheric boundarylayer treatments-a review. J .Climate, 1993, 6:419-449.[2]Xu LiRen, Zhao Ming. The influence of boundary layer parameterization schemes onmeso-scale heavy rain system. Adv. Atmos. Sci., 2000, 17:458-472.[3] Braun, S. A. and Tao W. K., Sensitivity of high-resolution simulations of hurricane Bob(1991) to planetary boundary layer parameterizations. Mon.Wea.Rev.2000, 128:3941-3961.[4] Burk, S. D. and W. T. Thompson, A vertically nested regional numerical weatherprediction model with second-order closure physics. Mon. Wea. Rev.,1989, 117:2305 -2324.[5]Holtslag, A. A. M .and C. H. Moeng, Eddy diffusivity and counter gradient transport in theconvective atmospheric boundary layer. J. Atmos. Sci., 1991,48:1690-1698.-513-