利用2001～2009年期间的MODIS遥感数据,结合地面能见度资料和近地面风场资料,通过个例和统计分析 了我国东部地区6月份气溶胶时空格局及其成因。结果表明: 1)MODIS监测的火点主要分布在32°N～35°N 东西向带状区域内, 气溶胶光学厚度(AOD)的高值区和监测到的火点高发区有着较好的空间对应关系。6月受到秸秆焚烧的 影响,整个东部地区的AOD达到全年最高。此外,地形和人类活动共同决定了东部地 区气溶胶的分布格局。2)安徽地区的能见度、霾日数以及AOD的逐月变化关系表明, 6月份夏收 季节大量焚烧秸秆,造成空气中颗粒物浓度升高,配合相应的气象条件使得整个东部地区的AOD均 有所上升。这进一步加重了东部地区的空气污染,形成了严重灰霾天气,从而导致能见度下降。 3)我国东部地区6月份AOD的时空变化(特别是年际变化)与近地面风场时空变化密切相关:风速 大值区,污染物容易扩散, AOD相对较低;风速小值区,即气流停滞区,水平扩散条件不好,污染 物浓度容易升高, AOD相对较高。

The Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 aerosol products (2001～2009) were used to study aerosol spatial and temporal distributions in June, as well as their variations with surface wind over East China. The results of case and statistical studies indicate that fire pixels almost dominate the whole northern Anhui and Jiangsu Provinces (32°N～35°N) in June. It is found that fire pixel count is quite large in June and clearly matches the high aerosol optical depth(AOD) loads during the burning month. These suggest that agricultural biomass burning occurs seriously in June, which leads to appearance of AOD peak values over East China. Moreover, the distribution feature of aerosol over East China has been proved mainly depending on topography and anthropogenic activities. The variabilities of visibility, days of haze and AOD in Anhui Province demonstrated that the agricultural biomass burning aerosols can also be transported into East China from the surrounding rural area in June. The spatial-temporal variabilities of AOD in June over East China are closely related to those of surface wind. On one hand, strong wind is favor for the diffusion of the pollutants, which leads to the relatively lower AOD loads. On the other hand, still wind process by which formation of airflow stagnation area can induce that the pollutants accumulate much easily, which leads to the relatively higher AOD loads.