ANALYSIS OF CIRCULATION SITUATION OCCURRING SANDSTORM IN THE NORTHERN CHINA

The sandstorm weathers in spring from 1981 to 1997 in the northern China are analyzed synthetically. The dynamic clustering method is used to divide the weather types to the day in sandstorm. Three of typical types are chosen, i.e., the northwest cold front type, the western trough and ridge moving type and the northern path type. The large-scale circulation situation and main weather systems of three types are studied. The basic characteristics of sandstorm weather are revealed. It is concluded that the clustering result can reflect objectively the basic weather types of sandstorm, which provides a path for the weather modeling method driven by data. It is the match of circulation situation in the high and the low altitude that results in sandstorm outbreak.