一次强沙尘暴过程中干空气侵入的数值模拟和诊断分析

Numerical Simulation and Diagnostic Analysis of Dry Intrusion in a Duststorm Process

利用非静力MM5模式对2004年3月26—28日主要发生在内蒙古中部偏北地区的强沙尘暴天气进行了数值模拟,并利用模式输出结果对这次过程进行了干空气侵入的诊断和分析。模拟和诊断分析结果表明,此次强沙尘暴过程中有明显的干空气侵入,这种干空气侵入将对流层高层高位涡带入低层,促进了对流层低层气旋及对流运动的发展,继而引起强沙尘暴的发生。

The mesoscale numerical model MM5 （ V3 ） was used to simulate a strong duststorm process occurred in the northern and central Inner Mongolia during the period from 20：OOBST March 26 to 20 ：OOBST March 28,2004. The model outputs were used for detailed diagnostic studies of dry air intrusion. Diagnostic results show that dry air intrusion plays an important role in the development of the duststorm process. Dry air intrusion brings high potential vorticity from the upper level of troposphere to the low level ,promoting the development of the cyclone and convective activities at the low level of troposphere,and then the genesis of the strong duststorm.