气溶胶光学厚度的分布特征及其与沙尘天气的关系

Distribution of Aerosol Optical Thickness and Its Relation with Dusty Weather in China

利用MODIS卫星遥感光学厚度资料,分析了中国大气气溶胶光学厚度的时空分布特征,并与同期沙尘天气进行了对比和相关分析,结果表明:①中国主要内陆地区的气溶胶光学厚度(Aerosol Optical Thickness,简称AOT)分布有4个高值区:①分别位于南疆盆地和青海、甘肃、内蒙古中西部地区、四川盆地和长江黄河下游地区。②春季北方特别是西北的AOT值明显高于南方,冬季南北AOT值差别不大。③南疆盆地和内蒙古中东部地区AOT值随季节变化明显,而四川盆地、长江黄河下游地区AOT值没有明显的季节变化。④南疆盆地、青海、内蒙古等地区沙尘天气过程与AOT值同步变化。⑤在沙尘天气的多发区,气溶胶光学厚度与沙尘天气有较好的相关性;沙尘天气的少发区,气溶胶光学厚度与沙尘天气基本不相关。因此可以推断,中国北方,特别是干旱荒漠区,大气气溶胶主要来自沙尘天气过程引起的地面沙尘释放。

The characteristics of temporal and spatial distributions of AOT in China have been analyzed based on the Atmospheric Aerosol Optical Thickness （AOT） from MODIS data. The relations between AOT and dusty weather were analyzed. Results indicated that： There are four regional high AOT-value centers in the main inland region of China： south Xinjiang Basin, Qinghai and Gansu, middle and west region of Inner Mongolia, Sichuan Basin, the lower reaches of Yangzi river and Yellow river. The aerosol optical thickness in the northern China is obviously higher than that in the southern China in spring, however, less different in winter. The seasonal changes of AOT are obviously in south Xinjiang Basin and middle-west region of Inner Mongolia, but not obviously in Sichuan Basin and the lower reaches of Yangzi river and Yellow river. In south Xinjiang Basin, Qinghai and Inner Mongolia, the temporal and spatial distribution of the dusty weather are similar with that of AOT. The atmospheric aerosol optical thickness has close correlation with the dusty weather in the area of more dust occurrence. According to the results above, in northern China especially in drought desert regions, the atmospheric aerosol mainly comes from the surface sand emitting due to dusty weather, and in southern China, mostly due to people＇s activities.