一次江淮大暴雨嵌套数值模拟试验

Multi-nested Numerical Simulation Experimentsof a Storm Rainfall over Yangtze River

利用 MM5非静力平衡模式 ,设计了未嵌套、两重和三重嵌套模式方案 ,对 1 999年 6月 2 3日一次江淮大暴雨过程进行了实际资料的降水个例试验 ,重点讨论了嵌套对数值模拟结果的影响。结果表明 :嵌套后 ,随着水平分辨率的提高 ,模拟的降水量越来越大 ;三重嵌套的中间层细网格已经可以把雨区范围、降水中心位置、降水强度比较接近实况地模拟出来 ,最内层细网格中模拟出若干个 β中等尺度降水中心 ;

The multi-nested numerical simulation experiments of a storm rainfall over Yangtze River on 23 June 1999 are conducted by nonhydrostatic model MM5. The effects of multi-nest to the result of simulation are discussed. The results of experiments show that: in nest-grid model, the amount of precipitation increases with the rise in horizontal resolution; the middle grid of three-nested grid can simulate rain area and the position of rain center and rainfall density accurately, some meso-β scale rain centers appear in inner grid; Mesoscale information in fine grid improves the simulation results in coarse grid; the fine grid increases the rate of nonconvective precipitation in coarse grid, but the extent of increase is finite.