Cairo F, Di Donfrancesco G, Adriani A, Pulvirenti L, Fierli F
Instituto di Fisica dell'Atmosfera del Consiglio Nazionale delle Ricerche, Aria di Ricerca di Tor Vergata, via Fosso del Cavaliere, Rome I-00133, Italy.
Appl Opt. 1999 Jul 20;38(21):4425-32. doi: 10.1364/ao.38.004425.
Different definitions for estimating the degree of changes in signal polarization measured by lidar measurements are used both to detect the presence of nonspherical aerosol particles and to estimate their shape and density. Our aim is to provide a tool for calculation and interpretation of changes in polarization that are due to aerosol backscatter measured by the lidar technique. An overview of several techniques used to calculate linear depolarization from two-channel lidar measurements is given. Advantages and disadvantages of each method are analyzed when we apply them on a lidar vertical profile. Systematic errors are also discussed. First, an overview of different estimations of polarizability of atmospheric molecules is given. The presence of signal with orthogonal polarization in each channel (cross talk) is a source of error in depolarization estimation. It is calculated at various degrees of contamination, and the total uncertainty on depolarization definition is retrieved.
用于估计通过激光雷达测量得到的信号极化变化程度的不同定义，既用于检测非球形气溶胶颗粒的存在，也用于估计其形状和密度。我们的目标是提供一种工具，用于计算和解释由激光雷达技术测量的气溶胶后向散射引起的极化变化。本文给出了几种用于从双通道激光雷达测量中计算线性去极化的技术概述。当我们将每种方法应用于激光雷达垂直剖面时，分析了它们的优缺点。还讨论了系统误差。首先，给出了大气分子极化率不同估计的概述。每个通道中正交极化信号的存在（串扰）是去极化估计中的一个误差源。计算了不同污染程度下的串扰，并得出了去极化定义的总不确定性。
