Calibration technique for polarization-sensitive lidars
Calibration technique for polarization-sensitive lidars
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DOI：
10.1175/jtech1872.1
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发表时间：
2006-05-01
影响因子：
2.2
通讯作者：
Winker, D. M.
中科院分区：
文献类型：
--
作者：
Alvarez, J. M.;Vaughan, M. A.;Winker, D. M.
事实证明，偏振敏感激光雷达在区分大气中的球形和非球形颗粒方面非常有效。这些激光雷达使用线性偏振激光器，并配备了一个接收器，可以分别测量平行和垂直于出射光束偏振的返回信号分量。在这项工作中，用于校准偏振敏感激光雷达的技术，最初是在美国宇航局的兰利研究中心（LaRC）开发的，并已在过去的15年中不断使用。该程序使用一个可旋转的半波片插入到激光雷达接收器的光路引入控制量的偏振串扰到一系列的大气后向散射测量。求解所得到的非线性方程组生成从激光雷达信号导出去偏振比的校准测量所需的系统校准常数（增益比和偏移角）。此外，该过程还确定了所分析的大气区域内的平均消偏振比。仿真和误差传播的研究表明，该方法是可靠的和良好的行为。该技术的操作细节说明使用测量获得的一部分，LaRC的参与第一次国际卫星云气候学项目区域实验。
Polarization-sensitive lidars have proven to be highly effective in discriminating between spherical and nonspherical particles in the atmosphere. These lidars use a linearly polarized laser and are equipped with a receiver that can separately measure the components of the return signal polarized parallel and perpendicular to the outgoing beam. In this work a technique for calibrating polarization-sensitive lidars is described that was originally developed at NASA's Langley Research Center (LaRC) and has been used continually over the past 15 yr. The procedure uses a rotatable half-wave plate inserted into the optical path of the lidar receiver to introduce controlled amounts of polarization cross talk into a sequence of atmospheric backscatter measurements. Solving the resulting system of nonlinear equations generates the system calibration constants (gain ratio and offset angle) required for deriving calibrated measurements of depolarization ratio from the lidar signals. In addition, this procedure also determines the mean depolarization ratio within the region of the atmosphere that is analyzed. Simulations and error propagation studies show the method to be both reliable and well behaved. Operational details of the technique are illustrated using measurements obtained as part of LaRC's participation in the First International Satellite Cloud Climatology Project Regional Experiment.