MM4模式积云参数化方案的改进和检验Ⅱ:改进模式的检验试验

Improvement and examination of the cumulus parameterization of MM4 model Ⅱ:examination of the improved version of the model

摘要:

为了检验用Fritsch-ChappeⅡ积云参数化方案改进的MM4模式^[1]对梅雨锋暴雨系统的模拟能力,初步确定该模式的稳定性、可靠性,用不同的侧边界条件、地形条件、行星边界层参数化方法进行了模拟试验,并将模拟结果与采用Kuo-Anthes积云参数化方案的模式模拟结果分别进行了比较。结果表明,改进模式对高度场和降水的预报均有改善,并能预报出-些细致特征。此外,改进模式对侧边界条件和地形极为敏感,而对行星边界层参数化方法的敏感性较弱,因此在模式侧边界条件选取和地形处理方面应十分谨慎。

Abstract:

Some numerical experiments are carried out with the improved MM4 model by incorporating with different lateral boundary conditions and topographic forcing as well as the different parameterization schemes of the planetary boundary layer.This helps us to understand the reliability of the model and to verify whether the model is able to simulate the Mei-yu front systems together with the storm events when the Fritsch-Chappell cumulus parameterization scheme is incorporated.A comparison is made between the simulation with Fritsch-Chappell cumulus parameterization and that with Kuo-Anthes scheme.It is found that the forecasting skill of geopotential height and rainfall is signifcantly improved in the improved MM4 model.The improved version of the model is very sensitive to the lateral boundary condition and the topography other than the parameterization scheme of the planetary boundary layer.It should be very careful if the lateral boundary condition or topographic forcing in the model is changed.