内蒙古“5.3”强沙尘暴天气成因分析

为了研究内蒙古中西部强沙尘暴发生发展机制，利用常规气象资料及NCEP1°×1°再分析资料，对2017年5月3—4日内蒙古中西部地区一次强沙尘暴天气成因进行分析。结果表明：（1）500 hPa低槽、蒙古气旋和地面冷锋是本次强沙尘暴天气过程的主要影响系统，此次强沙暴过程属于地面冷锋和蒙古气旋共同影响的类型；（2）分析高低层温压场与涡度平流发现，动力因子（涡度平流）和热力因子（温度平流）的共同作用，推动了蒙古气旋的东移发展；（3）垂直螺旋度分布特征是上负下正，表明沙尘区域上空高层为辐散区，有下沉运动，中低层为辐合区，有上升运动。

Strong Sandstorm in Inner Mongolia on May 3, 2017: Causes Analysis

By using conventional observation data and NCEP (1°×1°) reanalysis data, the strong sandstorm process in Middle-west Inner Mongolia on May 3-4, 2017 is analyzed, and a preliminary discussion about its formation cause is made in this paper. The results showed that: (1) The Strong sandstorm process belongs to the type of common effects of the surface cold front and the Mongolia cyclone. The 500hPa trough, the Mongolia cyclone, and the surface cold front were the main influences systems of the strong sandstorm process; (2) Vorticity advection（dynamic factor）and temperature advection（thermal factor）played a significant role in the development and eastward movement of the cyclone, by analyzing the field of temperature-pressure and vorticity advection on the higher and lower levels. (3) The helicity was negative at higher levels over the strong sandstorm area and positive at lower levels. This vertical distribution of helicity made great contribution to the formation and the development of the strong sandstorm.