北京地区沙尘暴天气分析及数值模拟

Weather analysis and numerical simulation of sandstorm in Beijing area

北京地区春季是风沙天气的多发季节 ,2 0 0 0年春季冷空气活动频繁 ,我国西北、华北多次出现大范围的沙尘暴天气 ,给人民的生活生产、交通运输及国民经济都带来很大的危害 ,而且沙尘天气造成的空气污染严重影响人们的身体健康。文中主要对 2 0 0 0年 4月 6日沙尘暴过程进行了天气分析 ,并用非流体静力中尺度数值模式进行预报和模拟研究。结果表明 ,此次沙尘暴天气是高空小槽沿大槽后强西北气流东移时发展加深 ,引导一次强冷空气南下所致 ;数值模式对沙尘暴到达北京地区的时间、地面风速、风向的突变都做出了很好的预报 ;沙尘暴发生时中低空有很强的垂直上升运动和正涡度中心 ,其形成、发展和移动与沙尘暴的过境时间和移动方向基本一致。同时利用空气质点轨迹模拟与分析方法进行了沙尘暴过程空气质点轨迹分析 。

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.