2013年春季内蒙古中东部地区一次吹雪过程天气学特征研究

为了研究内蒙古暴风雪成因，利用常规观测资料和NCEP2.5×2.5的6h再分析资料，应用Grads绘图软件以及Micaps3.2系统，对2013年出现在内蒙古中东部的一次吹雪天气进行了分析。结果表明：高空槽东南下为本过程提供有利的大尺度环流背景，蒙古气旋和蒙古冷高压为主要影响系统。高空急流在本次过程中起了重要作用。其出口区左前方的辐散抽吸作用，加强了地面蒙古气旋，有利于降雪发生。其入口区左侧的辐合区，形成下沉运动，动量下传以后为地面大风的形成提供条件。散度场和垂直运动场均形成次级环流，其辐合上升支为降雪提供动力抬升条件，而它的下沉支将高空动量下传到地面。西南低空急流的存在，将低纬度的暖湿气流输送到内蒙古中东部,对降雪天气的形成起了重要作用。

Synoptic Characteristics of a Blowing Snow Process During Spring of 2013 in the Eastern Region of Inner Mongolia

The paper aims to study the cause of snowstorm in Inner Mongolia, using conventional observation data and NCEP reanalysis data, applying Grads graphics software and Micaps3.2 system, the synoptic characteristics of a process of blowing snow during 2013 in eastern region of Inner Mongolia was analyzed. The results showed that: the upper trough that moved to southeast strengthening cold vortex provided favorable large scale circulation for blowing snow weather, the principal impact system of this blowing snow was Mongolian cyclone and Mongolian cold high. The strong high-level jet played an important role in this process. On the one hand, divergence suction on its left front of exit area so powerful that ground Mongolia cyclone developed strongly, was conducive to produce snow. On the other hand, the convergence zone on the left of the entrance, formed a descending motion, so that the momentum was following pass, for the formation of surface winds provided favorable conditions. Divergence and vertical field all formed a secondary vertical circulation, its convergence ascending branch provided impetus lifting conditions for snow, and its sinking branch downstreamed high altitude momentum to the ground, made surface wind speed increased. The existence of a southwest low- level jet in this process, combined with the warm advection, continually transported the warm air in low latitude to the eastern of Inner Mongolia, played an important role for the formation of the snow weather.