基于江西地区多卫星数据的气溶胶立体分布研究

Research of Aerosol Three-Dimensional Distribution Based on Multi-Satellite Data over Jiangxi

利用长时间序列（2007-2014年）的MODIS/Terra数据探讨了江西地区气溶胶光学厚度（aerosol optical depth,AOD）空间变化特征,发现该地区平均AOD呈现由南往北逐渐递增的趋势,其中,九江和南昌达到最高.同时,利用CALIPSO/CALIOP垂直特征掩膜获得了气溶胶层与云层的混合和分离状态,计算了气溶胶、不同子类型气溶胶和云的垂直概率分布和最大似然高度（maximum probability height,MPH）。结果表明：气溶胶主要聚集在1-3.5 km,气溶胶层和云层混合状态出现的概率高于分离状态。在2-4 km之间,春季污染沙尘出现的概率最高,冬季次之,夏季与秋季相当,而烟尘气溶胶夏季出现的概率最高,春、冬季相当,秋季次之。基于夜间CALIOP数据计算得到的气溶胶和云的MPH均表现出较大的季节差异性。

The spatial distribution characteristics of aerosol optical depth （AOD） over Jiangxi were analyzed by using long-term （2007-2014）MODIS/Terra AOD products. It is found that the average AOD varies greatly with locations and presents the increase trend from the south to the north. Among these cities, Nanchang and Jiujiang take the first place in terms of AOD value. At the same time, the mixture status of aerosol layer and cloud layer and the separated status were obtained based on CALIPSO/CALIOP vertical feature mask（VFM） data. Furthermore, the height resolved probability distributions of aerosol and its subtypes, as well as cloud, were calculated. More importantly, maximum probability height （MPH） of aerosol and cloud layers was figured out over Jiangxi Province and the surrounding region. Results indicated that aerosol particles mainly located at vertical levels of 1～3.5 km, and the occurrence frequency of mixture status of aerosol and cloud layers is much higher than that of separated status. During levels between 2～4 km, the highest occurrence frequency of ＂polluted dust＂ is in spring, followed by winter, and then summer and autumn. By contrast, the occurrence frequency of ＂smoke＂ aerosol is highest in summer, followed sequentially by spring, winter, and autumn. The MPH values of aerosol and ＇cloud, based on nighttime CALIOP data, exhibit large seasonal variation.