摘要
使用NCAR和NOAA的新一代中尺度模式WRF(WeatherResearchandForecast)和UCAR/PSU的MM5 (v3)模式 ,对 1998年发生在中国的三次强降水过程 ,即 5月的 1次华南暴雨过程 ,7月初的 1次淮河流域暴雨过程和 7月下旬的 1次长江流域暴雨过程进行了数值模拟。模拟结果表明 ,WRF模式能够成功模拟这几次不同性质的降水过程 ;与MM5对比 ,WRF更好地模拟了引起这几次降水过程中的主要天气系统的位置和移动过程 ,从而使WRF模拟的降水落区好于MM5。但在这几次过程中WRF模拟的降水都较MM 5为小 ,也小于实况值 ,分析可见 ,WRF模拟的垂直速度明显小于MM5的模拟结果 ,这可能是导致模拟的降水偏小的原因之一。
Numerical simulations are made with the new generation numerical model - WRF (Weather Research and Forecast) and MM5 on three typical heavy rainfall processes happened in 1998. The three heavy rainfall processes happened respectively over South China in May, over Huaihe reach at the beginning of July and over Yangtze river reach at the end of July. It is clear that the different results of the new meso-scale model - WRF can successfully simulate the rainfall processes which have different characteristic. And to all these three processes, WRF makes much better simulations than MM5, not only about the distribution of the precipitation, but also about the major weather systems. In all these processes, the movement of the major weather systems is simulated by WRF successfully, such as in the first process happened over South China, the cold air stream came from the North China and a vortex over the South China are both reproduced correctly by the model, and this good reproduction of the weather patterns could also be seen in the two other heavy rainfall process. It is clear that this is the main reason that WRF makes the better simulation of the distribution of the precipitation. But unfortunately, the maximum values of the precipitation center are much less than the results of MM5, and also less than the observations. From the numerical results, we found that the respectively small vertical velocity simulated by WRF can be considered as the major factor for the small precipitation.
基金
国家"十五"重点科技攻关计划"中国气象数值预报模式技术创新研究"(2 0 0 1BA60 7B)
