为了利用水面进行大气气溶胶粒子尺度分布的反演,需要水体光谱反射率资料;本文利用水库上空MODIS观测的表观反射率资料来订正出实际的水体光谱反射率。假设在干旱的春季水库水面反射率变化不大,用订正的水库水面光谱反射率平均值进行大气气溶胶尺度分布的反演。从两天个例研究来看,利用多通道MODIS资料可以反演出大气气溶胶粒子的尺度变化。结合天气分析2002年4月11日水库上空气溶胶光学厚度增加、粒子变粗,是由于上游区域的沙尘在高空强西北气流引导下到达本地区。

In order to retrieve aerosol particle size distribution over land,the spectral reflectance information of the surface water is needed.In this paper,the correction for the water spectral reflectanceof the Liujiaxia Reservoir is conducted by the 6S model with the MODIS data,on clear days under the conditions of low concentrations of aerosol.Supposing that the reservoir water spectral reflectance was less changing during the dry spring,the average results of the correction ofwater surface spectral reflectance of the reservoirwere used to retrieve the atmospheric aerosol particle size distribution.The atmospheric aerosol particle size distribution can be retrieved using the multichannel MODIS data from two days as example.The obvious reason for the explanation of aerosol larger sizeon 11 April 2002 is the dust transfer from the upwind areas,northwest of the study regions,by strong airflow,based on the analysis of the weather processes.