基于不动点原理的大气气溶胶消光系数边界值确定方法  

Determination of the boundary value of atmospheric aerosol extinction coefficient based on fixed point principle

作　　者：熊兴隆[1] 蒋立辉[1] 冯帅[2] 庄子波[3] 

机构地区：[1]中国民航大学天津市智能信号与图像处理重点实验室,天津300300 [2]中国民航大学工程技术训练中心,天津300300 [3]中国民航大学国际飞行学院,天津300300

出　　处：《光电子．激光》2012年第2期303-309,共7页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(41075013);中央高校基本科研基金(ZXH2011D003);中国民航大学科研启动基金(09QD14X)资助项目

摘　　要：提出了一种基于不动点原理的大气气溶胶消光系数边界值确定方法,其核心思想是将确定大气气溶胶消光系数边界值的问题转化为求解函数不动点。首先建立大气消光系数边界值与大气光学厚度和激光雷达回波信号之间的函数关系;其次依据函数不动点存在性和唯一性的条件估计不动点的存在,通过不动点迭代求得大气消光系数边界值,并由此值来确定大气气溶胶消光系数边界值。将本方法应用于实际激光雷达回波信号的反演中,得到低层大气气溶胶消光系数垂直廓线,并与在对流层顶使用洁净层法确定边界值所得的结果进行了对比。结果表明,利用本方法确定边界值,可以较为准确地反演出低层大气气溶胶消光系数。本方法可以预先估计不动点的存在区间、合理选取迭代初始值,具有收敛速度快、迭代次数少的优点,实际应用价值较强。In this paper a determination method for atmospheric aerosol extinction coefficient boundary value based on the fixed-point principle is proPosed. The core idea of the method is to convert the deterruination of the atmospheric aerosol extinction coefficient boundary value to searching for the fixed point of function. Firstly,the relationships between the atmospheric extinction coefficient boundary value and the optical depth of atmosphere as well as the return signals of lidar are established. Secondly,the existence of fixed point is judged according to the existence and uniqueness condition of function＇s fixed point, and then the atmospheric aerosol extinction coefficient boundary value is obtained by the fixed point iteration. The method is applied for real lidar return signals to invert the vertical profiles of lower atmospheric aerosol extinction coefficient, and it has been compared with the inversion results acquired by the clean layer method in the tropopause. The results show that the boundary value determined by this method can invert the lower atmospheric aerosol extinction coefficient well. This method can anticipate the existence interval of fixed point and select a reasonable initial iterative value. It has the advantages of fast convergence and few times of iterations.

关 键 词：激光雷达 不动点原理 气溶胶 消光系数 边界值 

分 类 号：TN249[电子电信—物理电子学]