川南城市群持续性污染过程个例分析

A Continuous pollution Episode Analysis in South of Sichuan Urban Agglomeration

2014年1月24日至2月1日,包括宜宾、泸州、自贡、内江、乐山在内的川南地区城市群发生一次持续性污染过程,期间多数城市达中度污染。为探究影响此次污染过程的气象条件,对比分析各城市API(Air Pollution Index)的变化趋势和天气形势,同时,利用ECMWF的模式层资料和常规地面观测资料分析边界层风场变化和地面温湿条件。研究结果表明,川南高空500 hPa盛行偏西风、低层暖平流、地面受均压场控制且气压梯度小,是形成此次持续性污染的主要原因。当高空出现持续性短波槽且低层逆温不明显,污染物程度明显下降;边界层风场变化同样是影响污染物堆积的主要气象因子。

From January 24 to February 1 in 2014, the urban agglomeration of southern Siehuan which includes Yibin, Luzhou, Zigong, Neijiang, Leshan has experienced a continuous air pollution event, the majority of them approached moderate pollution during the time. To explore the meteorological conditions of effecting the fouling processit compares the treads of urban API （Air Pollution Index） with the weather situafion, using the ECMWF model layer data and conventional ground observation data to analy the bo,andary layer wind field changes and the ground temperature and humidity conditions at the same time. Studies have shown that the prevailing westerly at 500 hPa upper the south Sichuan, the low-level warm advection, the uniform pressure field and small pressure gradient, are major causes of pollutants accumu- Lation. Once there is a persistent shortwave channel and the low-level temperature inversion is not obvious, the pollutant levels would decrease significantly;the change of the boundary layer wind field alsothe main meteorological factor affecting the accumulation of the pollutants in the region.