【摘要】 观测和数值模拟研究已经表明,潜热释放对中国东部夏季梅雨锋系统及其锋面降水的维持和发展发挥着非常重要的作用。然而,目前对于梅雨锋降水模拟中各种降水方案的相互协调和系统评估方面的工作仍不多见,为了增进对梅雨锋暴雨模拟中降水过程的认识,作者针对2003年7月4~5日一次梅雨锋暴雨过程,构造了四组试验,利用MM5模式考察了两种分辨率(36 km、12 km),各种隐/显式方案搭配下,对所生成的雨带、雨量和降水类型的配置进行了仔细的研究,得到了一些有意义的结论,为今后更好地使用模式、利用数值模式来认识中尺度降水过程中的气象问题打下基础。主要结论包括:模拟总降水的水平分布和强度,以及显式降水和隐式降水的划分对积云参数化方案的选择非常敏感。但对特定积云参数化方案而言,降水的模拟对36 km、12 km水平分辨率不敏感(除Betts-Miller方案外);在中尺度网格分辨率10~50 km范围内,不同积云参数化方案对梅雨锋降水分布和降水量模拟的影响比不同显式方案带来的变化大得多。更多还原

【Abstract】 Observational and numerical modeling studies have consistently shown that the latent heat release plays an important role in maintenance and development of Meiyu front and frontal precipitation.However,a systematic evaluation of precipitation parameterization schemes(including subgrid-scale convective parameterization schemes and resolvable-scale cloud microphysics schemes) in the simulation of a Meiyu front has been rare in the literature.In order to enhance our understanding of the precipitation process,4 sets of numerical experiments is constructed to evaluate the performance of implicit/explicit schemes which simulates the Meiyu frontal heavy rainfall on 45 July 2003 at grid resolution of 36 km and 12 km with MM5 model.Based on careful research on precipitation region and rainfall,some significative results have been got,which are good for further understanding and predicting mesoscale weather system using mesoscale numerical model.Principal findings are summarized as: The horizontal extent and intensity of precipitation,the partition of explicit precipitation and implicit precipitation are very sensitive to the choice of cumulus parameterization,but it is nearly the same on both the 36-km and 12-km grids for a given cumulus parameterization(except the Betts-Miller scheme);variations in the cumulus parameterization schemes have a much larger impact on the distribution and amount of Meiyu frontal precipitation than that in the explicit scheme at mesoscale grid resolutions of 10 km50 km.更多还原