激光雷达探测大气气溶胶雷达比和退偏比相关性分析及仿真研究

发布时间：2019-03-29 18:27

【摘要】：激光雷达是探测大气气溶胶光散射特性的有力工具。雷达比和退偏比是激光雷达探测气溶胶时的两个重要参量,二者存在着一定的相关关系。然而目前关于于雷达比和退偏比的研究多是独立进行,缺乏必要的交叉,限制了气溶胶光散射特性的深入研究。本文采用离散偶极子近似法研究了非球形气溶胶粒子的光散射特性,并通过相关性分析和数据拟合获得了雷达比和退偏比的相关关系。研究结果对气溶胶精细分类、气溶胶光学特性精细反演等均具有重要意义。论文首先采用离散偶极子近似法计算了不同形状、粒子取向和复折射率的单颗粒非球形气溶胶粒子的光散射特性,分析了各参数对雷达比和退偏比的影响。在此基础上研究了轴比对群体椭球气溶胶雷达比和退偏比的影响。当轴比增加时,沙尘气溶胶的雷达比先增大而后趋于稳定,其退偏比先增大后减小而后趋于稳定。煤烟粒子的雷达比和退偏比基本不受轴比影响,二者均随波长增加而减小。水溶型气溶胶的雷达比随轴比增大小幅度增大,退偏比随轴比增大先增大后趋于稳定,雷达比和退偏比均随波长增加而减小。不可溶型气溶胶个波长波长下的雷达比和退偏比基本一致,雷达比随轴比增大而增大,退偏比与轴比间的变化规律不明显。最后,研究了气溶胶组分对大陆型和沙漠气溶胶雷达比和退偏比的影响,利用皮尔逊相关系数分析了雷达比和退偏比间的相关性,并采用数据拟合建立了二者的相关性模型、研研结果表明大陆型气溶胶的雷达比和退偏比负相关,二次多项式拟合模型可精细描述二者的相关性。沙漠气溶胶的雷达比和退偏比呈负相关,线性拟合模型可以精细描述二者的相关性。
[Abstract]:Lidar is a powerful tool for detecting the characteristics of atmospheric aerosol light scattering. Radar ratio and depolarization ratio are two important parameters in detecting aerosol by lidar. There is a certain correlation between the two parameters. At present, however, most of the studies on radar ratio and depolarization ratio are independent and lack of necessary crossover, which limits the in-depth study of the scattering characteristics of aerosol light. In this paper, the light scattering characteristics of non-spherical aerosol particles are studied by using the discrete dipole approximation method. The correlation between radar ratio and depolarization ratio is obtained by correlation analysis and data fitting. The results are of great significance for fine classification of aerosols and fine inversion of aerosol optical properties. Firstly, the light scattering characteristics of single-particle non-spherical aerosol particles with different shape, particle orientation and complex refractive index are calculated by using the discrete dipole approximation method, and the effects of each parameter on radar ratio and depolarization ratio are analyzed. On this basis, the influence of axial ratio on the radar ratio and depolarization ratio of population ellipsoidal aerosol is studied. When the axial ratio is increased, the radar ratio of the dust aerosol increases first and then tends to stabilize, and the depolarization ratio increases first and then decreases, then tends to stabilize. The radar ratio and depolarization ratio of soot particles are almost independent of axial ratio, and both of them decrease with the increase of wavelength. The radar ratio of water soluble aerosol increases by a small extent with the increase of axial ratio, and the depolarization ratio increases at first and then tends to stabilize with the increase of axial ratio, while the radar ratio and depolarization ratio decrease with the increase of wavelength. The radar ratio and depolarization ratio of the insoluble aerosol at different wavelengths are basically the same. The radar ratio increases with the increase of the axial ratio, and the variation law between the depolarization ratio and the axis ratio is not obvious. Finally, the effects of aerosol composition on radar ratio and depolarization ratio of continental and desert aerosol are studied. The correlation between radar ratio and depolarization ratio is analyzed by Pearson correlation coefficient, and their correlation models are established by data fitting. The results show that the radar ratio and depolarization ratio of continental aerosol are negatively correlated and the quadratic polynomial fitting model can accurately describe the correlation between them. The radar ratio and depolarization ratio of desert aerosol are negatively correlated, and the linear fitting model can describe the correlation between them.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X831;TN958.98

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