Study On Predication And Characteristics Of Dust Weather In North-central Inner Mongolia

Xilinguole League is located in north of China, north-central of Inner Mongolia Autonomous Region. Its south are Zhangjiakou and Chengde, which are in Hebei Province, west is Wulanchabu,and east is Chifeng City, Xing'an and Tongliao City,as an intersection zone for northeast, north and northwest. Since Xilinguole League Grassland is climate regions of arid and semi-arid. and soil moisture is low, sands are distributed throughout the Xilinguole League. In particular, Midwestern Hunshandake across the mid-west of Xilinguole Grassland, which is an larger area in spatial, and has an important impact on Xilinguole League where the appearance of sandstorms occur every year. The sandstorms is one kind of severe weather, which bring much disaster and influence economic and environment. Therefore, research and analysis of development of sandstorms in Xilinguole League are very meaningful for predict service.Firstly, the trend and mutations of sandstorms in Xilinguole League are analyzed, the results show that, on the annual and seasonal scale, number of sandstorm days has a significant downward trend in Inner Mongolia North Central region, the most significant decrease trend occurred in spring, the smallest decline in autumn. Mutation in winter occurred earlier than in other seasons. The mutation changes of winter and the annual number of sandstorm days are in the late 80s of the last century, and the other seasons postponed to 90 mutations. Sandstorms in Xilinguole League changed from a relatively high state to low. The intensity, interannual variability, seasonal variability and spatial distribution of dust weather changed in consistent trends. Sandstorms in Inner Mongolia North Central region almost can occur in any duration of year, spring is the most frequent season. From the early 1980s to the late 20th century, sandstorm begins to decrease, but from 1997, it (start) a trend of increasing. During the 1981-2008, sandstorm is the most frequent severe weather,1990's is at the low stage. During 1961-1980, the number of sandstorm days occurred more than in 1981-2000, on spatial distribution, of sandstorms increases from east to west, the high-frequency center located at Suniteyouqi, the low incidence regions located at Wulagai Management District.The number of sandstorm days are closely related to meteorological factors:There is significant negative correlation between the annual precipitation and sandstorm days, high windy days positive relate to sandstorm days. There is no remarkable relationship between the annual average temperature and sandstorms days therefore, the local temperature is insufficient to forecast the sandstorms of next year.The number of dust weather days good relate with the underlying surface, soil moisture and vegetation on sand influence strongly dust weather, that is to say, there is a remarkable negative correlation between them. At the same time, there is some relation between the area terrain of Xilinguole League certain and sandstorms. Sand areas, the high plain areas become dust prone areas, hilly areas are less dust-prone areas.Sandstorm can divided into two type according to different types of the upper and surface weather system, cold front and the Mongolian cyclone type. The main large-scale circulation system generated sandstorm weather in Xilinguole League is the high-altitude cold vortex Mongolia, cold front, the Mongolia cyclone.