Weather analysis and numerical simulation of sandstorm in Beijing area

Strong wind and sand-dust storm often occurs in Beijing during spring. In spring ,2000, cold air were very active so that Northwest and North China experienced many sandstorm processes, which brought inconvenience and harm to people's living and life, to transport and national economy and as well as caused air pollution. In this paper, a case of sandstorm occurred on April 6th ,2000 was analyzed and simulated using non-hydrostatic meso-scale numerical model. The weather analysis indicated that weather process in this case was caused with the development of high-level small trough along with the strong northwest wind behind of a large trough during moving eastward and led a strong cold air to south. Numerical model gave a good forecast to the sandstorm appearing time and sudden change of surface wind over Beijing area. The simulated results showed that there were a strong vertical ascending motion and a strong positive vorticity center in mid and low level. These mesoscale structure's formation and development and movement were consistent with the passage and moving direction of sandstorm. The trajectory of air particle during the sandstorm process was also simulated and analyzed, which got the same results with the real situation and the trajectory monitored by meteorological satellite.