“8·19”甘肃区域暴雨的特征分析及数值模拟

Analysis and Numerical Simulation of the Heavy Rain in Gansu Province on 19 August 2004

分析了'8·19'甘肃区域暴雨发生的天气气候背景,不同层次的环流特征;重点分析了不同物理量场的变化,云系的演变;应用MM5中尺度非静力模式模拟了暴雨过程,并对模拟结果进行了分析.结果表明:'8·19'甘肃区域暴雨除了有利的天气系统配置外,低层强烈的风场辐合是导致暴雨的重要原因.强雨带的移动滞后于云顶温度最低的强对流云带;MM5对降水过程的强度、落区有较好的预报能力,尤其是12～48 h的预报效果相对最好,对强降水天气预报有较好的指示意义.

A regional heavy rain process occurred in Gansu province on 19 August in 2004 was analyzed from the weather and climatic background, circulation characteristics, as well as the change of different physical quantities and the evolution of the cloud cluster, at the same time it was simulated by MMS. Results show that the favorable weather condition and the convergence of the low - level wind are the main reasons of this heavy rain, the moving of the heavy rain zone lagged the strong convective cloud band on FY -2C houri）, satellite images. The simulated result indicates that MM5 is available for forecasting the intensity and location of the rainfall, particularly for 12 -48 hours rainfall forecasting, it has some significance for forecasting strong rainfall events.