“2002．3”华北地区强沙尘暴天气的螺旋度分析

On the helicity analysis of "March,2002" severe dust storm in north China

利用MM5非静力中尺度模式和螺旋度计算结果,对2002年3月18—22日华北地区发生的一次强沙尘暴过程进行了分析研究,重点分析了北京及周边地区水平与垂直方向螺旋度和完全螺旋度的结构变化及演变特征,结果表明:螺旋度的演变与强沙尘暴天气的发生、发展有较好的对应关系,将中尺度模式和螺旋度计算结合起来可以有效提高沙尘暴天气的预报准确度。

A numerical simulation of ＂March, 2002＂ severe sandstorm is analyzed by using nonhydrostatic mesoscale model MM5 and calculating helicity. The analysis mainly reveals the structural characteristics and evolvement of helicity in different directions. The result shows that there are close relationship between the evolvement of helicity and the process of dust storm, and that by using the mesoscale model MM5 and calculating helicity we can improve the accuracy of dust prediction.