【作者】 钟山；

【导师】 易帆；

【作者基本信息】 武汉大学 ， 空间物理学， 2012， 博士

【摘要】 大气是由多种气体和漂浮在其中的一些固态、液态物质颗粒所组成。颗粒物质有尘埃、烟雾、水珠、冰晶、花粉等。在大气科学中,通常把含有悬浮固态、液态粒子的大气称为大气气溶胶,而这些粒子则称为大气气溶胶粒子,简称气溶胶(王永生等,1987)。大气气溶胶吸收和散射太阳对大地的辐射,它作为凝结核与大气温度共同影响云、雨、雾、雪的形成,从而影响着地-气系统的辐射收支,对局地、区域乃至全球气候有着重要影响。利用大气分子的纯转动信号反演大气温度,被证明是一种精度很高的方法,目前已得到广泛的应用并在世界各地建立起多台纯转动拉曼激光雷达。全部的纯转动拉曼谱线之和是不依赖于温度的,利用这个特性,可以不需要任何的假设,反演大气气溶胶的消光。本文介绍了一种新的探测大气气溶胶的方法,首次提出通过提取纯转动单支谱(J=4和14),加上Rayleigh&Mie通道的激光雷达方程,不需要附加任何假设,我们导出了气溶胶后向散射系数的数学表达式,并且做了误差分析。分析表明,在8km处,光子计数为1600的情况下,大气后向散射系数的总误差应小于11.4%；4kmm以下的误差小于6.7%。为了提取纯转动拉曼散射的单支谱,需要采用F-P标准具和干涉滤光片组合的方式。本文介绍了F-P的温度特性、压强特性和角度对F-P标准具透过率函数的影响。还有生产工艺中的各种缺陷,对F-P标准具性能的影响。最后,比较了基于碘分子滤波器和F-P标准具的几种测风激光雷达性能。结果表明,基于双边缘碘分子吸收技术(de-IVF)的测风激光雷达和基于大气分子Rayleigh散射和F-P标准具组合(UV-FPI)的测风激光雷达能够兼顾气溶胶含量较多的低空探测和气溶胶含量较少的高空探测,适合做成具备高低空一体化测风能力的激光雷达。更多还原

【Abstract】 The atmosphere is composed of a variety of gases and floating in some of the solid and liquid particulate matter. These particulate matter include dust, smoke, water droplets, ice crystals, pollen and so on. In atmospheric science, the atmosphere containing suspended solid, liquid particles is usually known as the atmospheric aerosol, while these particles are called atmospheric aerosol particles. Atmospheric aerosol is the condensation nuclei of clouds, rain, fog, snow, which significantly influence the magnitude of radiative fluxes on the earth’s surface and within the atmosphere through the scattering and absorption of incoming solar and outgoing thermal radiation. Accordingly, aerosol have an important impact on local, regional and even global climate.It has been proved to be a high precision method to use pure rotational Raman signal of atmospheric molecules to inverse atmospheric temperature and many pure rotational Raman lidars have been established around the world. The addition of all pure rotation Raman spectrum is not dependent on the temperature. Using this feature, we can inverse aerosol extinction without any assumptions. This paper presents a new method of aerosol detection, extraction of pure rotational spectrum of a single branch (J=4and14), coupled with Rayleigh&Mie channel lidar equation, without any requirement of the additional assumptions. We derive the mathematical description of the aerosol backscatter coefficient. Furthermore, we do the error analysis, which shows the total error of atmospheric backscattering coefficient should be less than11.4%with1,600photons counting at8km and less than6.7%below4km.In order to extract the single branch spectrum of the pure rotational Raman scattering, we use the combination of the Interference Filter (IF) and F-P etalon. This article describes the temperature, the pressure and the incidence angle characteristics of the F-P etalon transmittance function. There are also a variety of defects in the production process which influence the performances of F-P etalon significantly.At the end, we compare two wind measurement methods, using iodine vapor filter and Fabry-Perot interferometer, respectively. The results show that, lidar based on double-edge of iodine vapor filter(de-IVF) and the combination of atmospheric molecular Rayleigh scattering and F-P etalon(UV-FPI) can take into account the more content of aerosol at low-altitude detection and less content of aerosol at upper-altitude detection. They are suitable to be made of both high and low altitude wind detection lidar.更多还原