一维最大概率法反演夜光云散射系数廓线的研究

Inversion of the Scattering Coefficient of Polar Mesospheric Clouds by Using One-Dimensional Maximum Probability Method

介绍了最大概率法的数学原理及迭代方程的使用过程,以卫星遥感观测的夜光云数据为例,阐述了最大概率法在实例中的使用方法,并反演得到了夜光云体散射比廓线及散射系数廓线。与传统洋葱剥皮法的反演结果进行对比,结果表明:最大概率法的结果几乎没有失真现象,但洋葱剥皮法得到的散射比存在严重的失真现象。其根本原因在于传统方法假设夜光云体散射强度值在大气层结中为均匀分布,而最大概率法则假设体散射强度值在层结中可以在一定的变化范围内呈现不均匀的分布,后者的假设更符合夜光云这类短时间内可能会出现大幅值空间分布变化的自然现象。

Both the mathematical principle of the maximum probability （MP） method and the process of iterative equations are introduced. Then we use the real satellite data as an example to demonstrate the calculation of MP method and obtain the volume scattering ratio profiles and scattering coefficient profiles of polar mesospherie clouds （PMCs）. We compare the inversion results of the MP method with those of the traditional onion peeling fOP） method, and find that the former hardly have any distortion, while the latter show serious distortion. The fundamental reason for this difference is that the OP method assumes that the volume scattering intensity has a uniform distribution in the same atmospheric layer, while the MP method assumes that the volume scattering intensity can exhibit a non-uniform distribution within a certain varied range of the layer. This assumption of MP method is more suitable for the natural characteristics of PMCs, because the spatial distribution of PMCs often changes greatly in a short time.