【摘要】 本研究对2002—2015年内蒙古春季共16次大范围、强沙尘暴天气过程做了调查分析,在分析欧亚范围中高纬地区海平面气压场、500hPa高度场、地面和850hPa温度场的分布及演变特征后,确定了引起内蒙古地区强沙尘暴的影响关键区,重点关注了海平面气压场关键区的环流分布特征,将16次强沙尘暴过程划分为蒙古气旋型、冷锋型和副冷锋型。研究结果显示:三个类型的海平面气压场均为西高东低型分布,蒙古气旋型和冷锋型在关键区中均存在高、低压中心,其强度和位置,以及它们之间的等压线梯度和走向存在明显差异。副冷锋型的低压位置比其他两个类型明显偏向东北,关键区内高压中心不明显。500hPa高度场三个类型的关键区均为西北气流控制,蒙古气旋型中间略偏西北位置存在一个浅槽,冷锋型环流经向度比其他两个类型偏大,副冷锋型的中间略偏北位置存在一个低值中心。在温度场关键区的最大增温线上,从沙尘最强日的前4日至过后1日地面和850hPa温度计算结果显示:各类型在强沙尘暴来临的前几天均有一个增温趋势,前两类温度曲线均在前一日达到最高点,随后明显下降,蒙古气旋型的增温幅度及随后的降温均比冷锋型小,副冷锋型温度变化曲线与前两者有所不同,未表现出降温现象。更多还原

【Abstract】 In this study,we investigated all of 16 large and severe dust storm events observed in Inner Mongolia during the springs of2002—2016.It has some crucially influential regions were identified after analysing the atmospheric circulation revolutionary of the surface pressure level,500 hPa geopotential height(500Z),surface and 850 hPa temperatures over the area of the med-high latitude of the Eurasia section.Much attention is focused on features of the crucial region in order to sort the circulation types and to find their different characters.The 16 events were classified into three types as Mongolian Vortex,Clod Front and Secondary Clod Front.The results indicate that the all three types display the same west-high and east-low distribution feature of pressure centers.In addition,there is a high and a low center can be viewed in the crucial regions of the Mongolia Vortex and Cold Front types.Locations,intensities,pressure gradients and isobars directions between high and low centers present different configurations for those two types.The low center of the Secondary Clod Front locates in more northeastern position than the other two types,and its high center does not manifest in crucial region.The crucial regions of all three types are controlled by northwest flow at 500 Z.There is a shallow trough can be seen at the little bit northwestern position of the Mongolia Vortex type.The biggest meridional gradients exist in the Cold Front and there is a low center in the Secondary Clod Front type.Furthermore,calculation outcomes of the temperature variations on the biggest temperature increasing line in the crucial region shown that all types displaying an increasing trend of temperature at the surface and 850 hPa during the previous 4 days of dust storm attacked day.Both of the Mongolia Vortex and the Cold front has a highest temperature point appeared on the previous day of the dust storm attacked day,and then,the temperature decreasing quickly after the day of dust storm.The increasing and decreasing fluctuations of the Mongolia Vortex are weaker than that of the Cold Front type.The temperature variation of the Secondary Clod Front is quite different from the other two types.It does not perform a declining trend of the temperature after dust storm attacked day.更多还原