MM5水平嵌套方案对降水预报影响的敏感性试验

利用MM5对2003-2005年华东地区的3次暴雨过程数值模拟,通过采用3种水平网格嵌套方案做对降水预报影响的敏感性试验,研究模式水平率对降水强度和落区预报的影响。结果表明:随着水平网格精度提高,模式对中小尺度天气系统的模拟能力增强,地形对天气过程的影响反映更加全面,模拟的雨带分布也越接近实况,雨量中心强度也随之增大;三层嵌套网格在暴雨落区和暴雨量级的预报上均优于两层和一层水平网格嵌套方案,尤其是暴雨落区预报有很大优势。

The Sensitivity Experiment on the Effect of MM5 Horizontally Nested grids to Precipitation

Based on the heavy rain which happened in east china in 2003,2004 and 2005,using the MM5 model to simulate,the simulation mainly research the effect of the change of horizontally nested grids on the numerical simulation results and precipitation area.The results show that: by the increasing of horizontally nested grids resolution,the sensitivity on meso and small scale system enhance.More comprehensive to the affect of the topography more precise to precipitation simulation,is precipitation centre more close to actual situation and precipitation intensity become more strength..The three level nested model is superior to one level and two level nested model no matter on the heavy rain area forecast or on quantitative forecast.In large quantitative forecast,it's necessary to use the three model nested grids,Especially in heavy rain area forecast.