一次区域性大风沙尘暴天气成因分析

Diagnosis Analysis of a Gale and Sandstorm Weather Case

应用基本观测资料和我国数值预报产品HLAFS资料,对2004年3月2日由西伯利亚冷槽东移南压并强烈发展,在河西走廊东部武威市形成的一次区域性大风、沙尘暴天气过程,从天气学成因、动力机制等方面进行了诊断分析。结果表明,强冷空气的卷入使西伯利亚冷槽强烈发展,为沙尘暴的发展提供了动力条件,而西伯利亚冷槽的垂直结构为沙尘暴提供了动量下传机制,地面冷锋后部形成的大风,为沙尘暴的形成创造了基本条件,在此基础上得出了西伯里亚冷槽的预报着眼点。

Using data of basic observation and numerical forecasting product HLAFS, we analyzed the synoptic causes and forcing mechanism of a gale and sandstorm weather process in March 2nd of 2004 in Wuwei city of Hexi corridor. This weather process was formed under the Siberian Cold Trough moving towards southeast and developing greatly. The involvement of very cold air made the Siberian Cold Trough develops further, which provided the forcing condition for sandstorm. The vertical structure of Siberian Cold Trough provided the mechanism of momentum transmitting downwards for sandstorm. The gale at rear of ground cold front created the basic condition for sandstorm. Accordingly, we got the starting point of forecasting sandstorm.