甘肃临夏地区一次扬沙与强寒潮天气诊断分析

Examining on a Blowing Sand and Strong Cold Current Event over Linxia Region of Gansu Province

利用基本气象资料和欧洲中心数值预报产品资料，对发生在2006年4月10～11日临夏地区的一次扬沙和强寒潮天气过程进行了分析。结果表明：临夏地区扬沙伴有强寒潮天气发生，在大气环流调整过程中，冷空气活动是造成扬沙和强寒潮灾害的主要动力，高空急流是大风的动量来源，蒙古气旋和冷锋是触发这次扬沙、强寒潮天气的重要天气系统。高、低空冷、暖平流的空间配置使降温更为剧烈。同时，涡度和散度对扬沙和寒潮的落区有很好的指示作用。在受灾区，对流层和近地面层为不稳定层结，从而引起强烈垂直上升运动，导致低层强烈辐合。

Based on the meteorological data and the ECMWF numerical forecasting products, in this paper a blowing sand and strong cold current event occurred over Linxia region of Gansu Province on April 10 to 11, 2006, is analyzed. The results show that the movement of cold air mass in atmospheric circulation was the main power of the weather event of blowing sand and strong cold current, the upper-air jet flow was the momentum source of strong wind, and the Mongolian cyclone and cold front were the important weather systems to trigger the weather event of blowing sand and strong cold current. The temperature was drastically dropped by the spatial pattern of cold advection in the upper-air layer and of warm advection in the lower-air layer. Moreover, the distribution of vorticity field and divergence field had a good indication to the occurrence areas of blowing sand and strong cold current. In the damage area of blowing sand and strong cold current on April 10 to 11, the troposphere and the near-ground layer were unstable, thus a violent vertical movement was resulted in to form a violent lower-level convergence.