无盲区CCD激光雷达的边界层气溶胶高分辨垂直廓线探测方法研究

At present，haze events occurr frequently. It is very important for human health and climate change that measurement on aerosol with high vertical resolution in the boundary layer. Affected by blind area and overlapped region, the results of conventional mono-static aerosol Mie lidar are usually not correct. A new detection method is proposed in this project, which high vertical resolution of aerosol would be measured in the lower boundary layer, using CCD lidar with no blind area. Researchs presented in this application will focus on several aspects. Firstly, The theoretical model will be set up for high vertical resolution distribution of aerosol in the lower boundary layer using a CCD lidar equation. Sensitivity analysis of aerosol scattering phrase function to aerosol extinction vertical profile retrieving will be developed. Solution to a CCD lidar equation will also be looked for. Secondly, method study and experimental detection will be focused on retrieval of aerosol scattering phrase function from CCD lidar images. Accurate results of scattering phrase function including 0-180 degree can be achived. Finally, Using CCD liar experiments will carried out for high vertical resolution distribution of aerosol in the lower boundary layer, with a most resolution of 1meter. Under different weather conditions, aerosol vertical fine distribution and its temporal-spatial variations will be observed between near ground to several hundreds of meters. Reliable data service will be gived for for the study of climate change.

灰霾事件频发的今天，边界层底部气溶胶的分布探测对人类健康和气候变化的研究具有重要意义。受限于系统盲区和几何因子的影响,常规单端米散射激光雷达的近端测量结果通常存在误差.为此，本项目提出利用CCD激光雷达无盲区的探测边界层底部气溶胶的垂直分布的新方法。 本项目拟从理论分析和数值仿真着手，基于CCD激光雷达方程建立近地面层气溶胶垂直廓线分布反演的理论模型，开展散射相函数对大气消光系数反演的敏感性分析，寻找CCD激光雷达反演气溶胶垂直廓线的约束解；开展CCD激光雷达反演散射相函数的方法研究和实验探测，精确获得散射相函数的全角度（0-180度）的分布；最后利用CCD激光雷达开展边界层底部气溶胶高分辨垂直廓线分布的实验研究,最高空间分辨率预计达1米，选择不同天气条件下长期实验结果，分析近地面至几百米高度范围大气气溶胶分布的精细结构及时空间变化规律，为气候环境变化的研究提供可靠的数据服务。

近地面层大气气溶胶廓线分布与人类健康和环境保护息息相关，激光雷达可以较为准确的探测大气成分的廓线分布，但由于系统盲区和几何因子的存在，致使雷达近端测量结果存在较大误差，探空气球等可以获得大气参数廓线分布，但空间分辨率低而且不能连续进行探测，为此本课题开展了基于CCD侧向激光雷达的近地面大气气溶胶高分辨垂直廓线探测研究。.首先，推导了CCD侧向激光雷达方程以及由此反演气溶胶消光系数的理论公式，利用大气分子和气溶胶消光系数分布模式，仿真计算了CCD侧向激光雷达的回波信号分布，分析给出了CCD像素与实际垂直距离及距离分辨率的对应关系，结果表明CCD侧向激光雷达在近地面探测中具有米散射激光雷达不可比拟的高空间分辨率的优势。.其次，对实验室现有CCD侧向激光雷达探测系统进行了技术上的升级改造，实现了白天强背景条件下，近地面气溶胶消光系数的CCD激光雷达实验探测，采用移位相减法和高斯拟合算法对图像信号进行提取使得反演得到的气溶胶消光系数的测量结果更加精确。.再次，利用米散射激光雷达同时测量的结果验证了CCD激光雷达测量结果的可靠性，而与前者相比，CCD激光雷达具有不受几何因子和盲区限制的优势。开展了近地面气溶胶昼夜时空间分布的探测研究，结果表明近地面气溶胶消光系数廓线变化比较复杂，受人类活动等影响大。.最后，分析了 CCD侧向激光雷达测量大气退偏振度和散射相函数的方法并初步开展了实验探测，为近地面大气多参数综合分布测量提供了可能。CCD侧向激光雷达技术的发展为环保部门获得近地面颗粒物随时空的分布规律提供数据支撑，进一步防控近地面空气污染提供科学依据。