2011年长春市一次持续浮尘天气成因分析

Forming reason of a continuous floating dust event in 2011 in Changchun

利用气象探测资料和环境监测数据,采用统计分析、环流演变分析、物理量诊断以及后向轨迹法分析了长春市浮尘发生的气候特征和2011年5月12日长春市出现的一次持续时间较长、污染程度较重的浮尘天气过程。结果表明:长春地区浮尘天气整体上呈波动性减少趋势,3—5月是主要发生时期;本次浮尘天气过程沙源来自蒙古国中部和内蒙古中东部,并随高空急流的输送影响东北地区,本地沙源没有补充;高空急流明显、地面风速较小、温度露点差较大、内蒙古东部辽宁省北部存在弱风区、整层大气稳定是该区域未出现沙尘暴而出现浮尘的主要原因。

Based on the meteorological and environmental data, a continuous floating dust pollution event on May 12,2011 in Changchun was analyzed by methods of a climate statistics, a circulation evolution, a physical diagnosis and a back trajectory analysis. The results show that the annual dust day is in a fluctuant decreasing trend in Changchun. The dust weather mainly occurs during March to May. The sand source is originated from the central Mongolia and mid-eastern of Inner Mongolia, and the dust is transported to northeast China with upper jet stream. There is no local sand source in this process. It is a continuous floating dust process rather than a sandstorm because of obviously upper jet stream, smaller surface wind speed, larger temperature dew point difference, weak wind areas in the eastern Inner Mongolia and northern Liaoning province and stable atmosphere in the whole layer.