关键词: 沙尘暴, 成因, 土壤湿度, 温度, 降水, 大气环流, 纬向风

Abstract:

There occurred totally 7 sand-dust weather processes,  including 4 sandstorm processes and 2 severe sandstorm processes, in northern China in 2011. In comparison to the long-term means, the frequency of the sand-dust weathers was lower, the intensities of the sand-dust weathers were bigger, and the affected area was larger. The possible driving factors on the characteristics mentioned above were as follows: (1) The lower atmosphere temperature in the winter of 2010/2011 was beneficial to keep the soil frozen longer. Although the precipitation amount was less in the studied area in the winter of 2010 and spring of 2011, which led to a bad vegetation condition in the spring of 2011, the atmosphere temperature was still lower and the soil thawed out lately, which might restrain the occurrence of the sand-dust weathers in early spring, thus resulted in the fewer sand-dust weather processes in 2011. (2) The soil moisture content was higher in the studied area in the winter of 2010 and spring of 2011 than that in the other years, suggesting that the fine soil particles could not be blown up easily to form a sand-dust weather process; (3) In the spring of 2011, in most regions of Mongolia and Inner Mongolia, the zonal wind was the negative anomaly of westerly wind, which goes against the dust emission and conveying the dust particles to east.

Key words: sandstorm, driving factors, soil moisture, atmospheric temperature, precipitation, atmospheric circulation, zonal wind