Categorical Characters of Large and Severe Dust Storm in Inner Mongolia during 2002-2016
In this study, we investigated all of 16 large and severe dust storm events observed in Inner Mongolia during the springs of 2002—2016. It has some crucially inlfuential regions were identiifed 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 ifnd their different characters. The 16 events were classiifed 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 conifgurations 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 lfow at 500Z. 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 lfuctuations 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.
severe dust stormcategorical characterscrucial regiontemperature increasing linebarometric gradient
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