华北平原夏收期间气溶胶卫星遥感探测分析

为研究2014年华北平原在夏收期间气溶胶污染的时空分布特征及形成原因,对2014年6月MODIS卫星的华北平原的气溶胶光学厚度(AOD)、细粒子比(FMF)、火点分布及后向轨迹进行了分析.结果表明,2014年6月华北平原的气溶胶光学厚度值在1.2~2.0之间,远高于年平均值1.0~1.2,而6月的火点分布主要集中在6—14日,此阶段的气溶胶光学厚度值高于6月6日前及14日以后的气溶胶光学厚度值.在两个特定研究区——华北南部及长三角地区,通过对6月的3个阶段的细粒子比进行分析,发现火点集中阶段细粒子排放增多,确定此次污染极有可能是由秸秆燃烧造成.在火点集中时期,两个研究区的后向轨迹说明,污染主要来自火点分布密集区域,进一步确定了秸秆燃烧是华北平原在夏收期间的主要污染源之一.

Aerosol detection analysis from satellite during the harvest season over North China Plain

To investigate the aerosol pollution distribution pattern over the North China Plain during the harvest season of 2014 and the underlying reason, MODIS aerosol optical depth (AOD), aerosol fine mode fraction(FMF), fire hotspots, and backward trajectory in June 2014 were analyzed. Results showed that the average AOD ranged from 1.2 to 2.0 in June, much higher than the annual average AOD of 1.0~1.2 in 2014. The fire hotspots were primarily concentrated during the period of June 6-14, leading to higher AOD values. Fine particle increased at southern North China Plain and Yangtze River Delta during the period with intensive fire hotspots detected by MODIS, which could be likely due to straw burning. Backward trajectory analyses further confirmed that air pollution basically originated from regions characterized by heavy fire spots. Both MODIS AOD and backward trajectory analyses showed that biomass burning during harvest season resulted in heavy aerosol pollution episodes.