基于侧向激光雷达的大气颗粒散射特性研究

发布时间：2018-11-16 09:14

【摘要】：本文针对激光雷达和大气颗粒散射性质做了以下研究:(1)对课题的研究背景做了简单的介绍,重点讲述了激光雷达的分类及特点,以及PM2.5监测方法及其相应的优势和探测大气气溶胶的发展历程和现状。(2)主要介绍了高斯光束的特点以及在真空中的传输特性,讲述了大气的组成成分,以及大气气溶胶与光子的相互作用,重点讲述了Mie散射理论,详细讲解了利用蒙特卡罗方法建立光传输的模型和CCD原理。(3)根据侧向散射激光雷达方程和Mie散射理论,建立了PM2.5浓度与侧向散射光强的关系模型,提出了一种基于CCD实时监测近地面PM2.5浓度的方法。设计了以波长为532nm的激光器为光源,CCD为接收器的侧向散射激光雷达装置,利用该装置测量了散射角在o o15~45之间侧向散射回波信号图。对比赛默飞世尔科技公司的PM2.5浓度测量仪SHARP测得的数据,拟合了PM2.5浓度与3个灰度等级光总能量模型,拟合度均在0.97以上。该装置具有操作便利,移动便捷,实时监测,成本较低的特点,在近地面比后向散射激光雷达具有更高的精度与实用性,有助于了解PM2.5的污染情况,建立PM2.5的运动趋势并进一步得到污染地图。(4)为反演大气侧向散射系数廓线,测量了散射角在o o33~145范围内的大气侧向散射光强。提出了一种有效降低实验噪声的新方法,并绘制了六种原始回波信号伪彩图,将空间散射角转化为平面散射角,从而找到了一种处理CCD像元与散射角对应关系的新方法,大大简化了计算。为研究激光探测水平方向大气气溶胶的多次散射问题,本文建立了基于蒙特卡罗的侧向散射激光雷达仿真模型,利用半解析的蒙特卡罗方法和严格的仿真参数,得到了光子检测器接收的光子总权重归一化值的空间分布规律,对比侧向散射激光雷达实验处理结果,两个具有相近的趋势并且吻合度较高,这能给借助激光雷达探测大气气溶胶提供了一定理论指导和预测作用。
[Abstract]:In this paper, the characteristics of lidar and atmospheric particle scattering are studied as follows: (1) the research background of the subject is introduced briefly, and the classification and characteristics of lidar are emphasized. The PM2.5 monitoring method and its relative advantages as well as the development and present situation of atmospheric aerosol detection are introduced. (2) the characteristics of Gao Si beam and its propagation in vacuum are introduced, and the composition of atmosphere is described. And the interaction between atmospheric aerosols and photons, the theory of Mie scattering is emphasized, and the model of light propagation using Monte Carlo method and the principle of CCD are explained in detail. (3) according to the Lidar equation of lateral scattering and the theory of Mie scattering, A model of the relationship between the concentration of PM2.5 and the intensity of lateral scattering light is established, and a method of real-time monitoring the concentration of PM2.5 near the ground based on CCD is proposed. A side scattering laser radar device with wavelength 532nm laser as light source and CCD as receiver is designed. The scattering angle between o 1545 and o 1545 is measured by this device. The data obtained from the PM2.5 concentration measuring instrument SHARP of Commevier Technology Company are fitted with the total energy models of PM2.5 concentration and three grayscale grades, and the fitting degree is above 0.97. The device has the advantages of convenient operation, convenient movement, real-time monitoring and low cost. It has higher accuracy and practicability than backscattering lidar near the ground, and is helpful to understand the pollution of PM2.5. The movement trend of PM2.5 is established and the pollution map is obtained. (4) in order to retrieve the profile of atmospheric lateral scattering coefficient, the intensity of atmospheric lateral scattering light with scattering angle in the range of o _ (33) ~ (145) is measured. In this paper, a new method for reducing experimental noise is proposed, and six original pseudo-color images of echo signal are drawn. The spatial scattering angle is transformed into plane scattering angle, and a new method to deal with the relation between CCD pixel and scattering angle is found. The calculation is greatly simplified. In order to study the problem of multiple scattering of atmospheric aerosols in horizontal direction by laser detection, a simulation model of Lidar based on Monte Carlo is established in this paper. The semi-analytical Monte Carlo method and strict simulation parameters are used. The spatial distribution of the normalized value of the total photon weight received by the photon detector is obtained. Compared with the experimental results of the Lidar, the two have similar trends and the degree of agreement is high. This can provide some theoretical guidance and prediction for atmospheric aerosol detection with lidar.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X831;TN958.98

【相似文献】