Abstract:

The fifth generation PSU /NCAR’s non - hydrostatic mesoscalemodel ( MM5 ) is app lied to simulatemeteorological fields of the dustweather affecting Beijing in North China on 21March 2001. The results show the model is capable for simulating and p redicting spatial and temporal variations of dustweather in Northern China. Low - p ressure system and its vertical structure of high - level divergence and low - level convergence resulted in strong updraft causing dust emission, and strong wind was dynamic condition for transmission of sand dust. The trajectorymodel is app lied to simulate the air particle trajectory, which commendably reflects source area and transmission trajectory of sand dust. The p redicted area of dust storms is in good agreementwith those ofmeteorological observation and satellite images. The software is p rogrammed to demonstrate dynamic p rocess of the meteorological fields.

Key words: dustweather, meteorological fields, numerical simulation

摘要：

利用PSU /NCAR的非静力中尺度气象预报模式MM5对北方地区气象场进行模拟,通过对2001年3月21日发生并影响北京地区的沙尘过程的数值实验表明,该模式能够较好地模拟和预测北方沙尘天气的时空演变特征。低值系统以及其低层辐合、高层辐散的垂直结构,可以产生很强的上升气流,形成地面起沙和沙尘上扬,而强风是沙尘输送的动力条件。利用轨迹模式对空气质点轨迹进行了模拟研究,可以较好地反映沙尘的发生源区和输送路径,与卫星监测和天气系统分析是一致的。并编写软件用于演示气象场的动态效果。

关键词: 沙尘天气, 气象场, 数值模拟