典型地区大气气溶胶谱分布和折射率特征研究

发布时间：2018-01-14 08:04

本文关键词：典型地区大气气溶胶谱分布和折射率特征研究　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：大气气溶胶由于其复杂的影响机制和在气候中的重要作用,已成为目前的研究热点之一。大气气溶胶粒子谱分布和复折射率m(m=nr-ini,nr是折射率实部,ni是折射率虚部)是气溶胶的重要物理参量,特别是其复折射率是模拟气溶胶辐射效应必须知道的物理参量。我国疆域辽阔,地形与气候复杂多样,不同区域气溶胶源差异很大,因此研究典型地区气溶胶的光学参数特征尤其是气溶胶复折射率特征是很有意义的。本文利用Mie散射理论结合OPC-06光学粒子计数器、黑碳仪、积分浊度仪和能见度仪等仪器近地面测量的气溶胶微物理和光学特性,反演出新疆、天津、厦门和合肥四个典型地区的大气气溶胶复折射率,并分析了这四个典型地区的吸收和散射系数以及气溶胶粒子数浓度谱分布。此外本文还重点利用OPC-06光学粒子计数器测量出的气溶胶粒子数浓度谱,利用对数正态分布拟合城市型、乡村型、沙漠型和海洋型四种类型气溶胶粒子的数浓度谱分布。主要结论如下:(1)天津地区、厦门地区和合肥地区的气溶胶谱分布由Junge分布和对数正态分布共同描述,其中间模态均为对数正态分布,峰值中心分别在0.80、0.86和0.54 μm,符合城市气溶胶的特征;而新疆地区的气溶胶谱分布则由Junge分布来描述。(2)新疆地区、天津地区、厦门地区及合肥地区的大气气溶胶折射率实部nr都在1.50左右,折射率虚部ni分别为0.010、0.017、0.008和0.016。(3)天津地区、合肥地区和厦门地区的消光系数和吸收系数随波长的变化趋势一致,在长波波段几乎不变化;在新疆地区,短波波段消光作用明显,而在长波波段则是吸收作用明显。(4)城市型气溶胶、乡村型气溶胶、沙漠型气溶胶和海洋型气溶胶的数浓度谱分布基本上都上由三段对数正态分布拟合叠加而成。城市型气溶胶中间模的模半径在1μm附近。乡村型气溶胶和沙漠气溶胶则主要有两个细粒模,其中乡村型气溶胶的粒子浓度较低。海洋型气溶胶的中间模的半径同样在1μm附近,不过主要是由于海盐飞沫。太平洋海域没有粗粒模,沙漠型气溶胶夏季时粗粒模的浓度最大。
[Abstract]:Atmospheric aerosol has become one of the research hotspots in recent years because of its complex influence mechanism and important role in climate. Atmospheric aerosol particle spectrum distribution and complex refractive index mnr-ini have become one of the hotspots. Nr is an important physical parameter of aerosol, especially its complex refractive index is the physical parameter which must be known to simulate aerosol radiation effect. Our country has a vast territory. The topography and climate are complex and diverse, and the aerosol sources vary greatly in different regions. Therefore, it is significant to study the characteristics of aerosol optical parameters, especially the complex refractive index of aerosols in typical areas. In this paper, we use Mie scattering theory combined with OPC-06 optical particle counter, black carbon meter. The microphysical and optical properties of aerosol measured near the ground by means of integrated turbidimeter and visibility instrument are used to reverse the atmospheric aerosol complex refractive index in four typical regions of Xinjiang, Tianjin, Xiamen and Hefei. The absorption and scattering coefficients of the four typical regions and the distribution of aerosol particle number concentration spectrum are analyzed. In addition, the aerosol particle number concentration spectrum measured by OPC-06 optical particle counter is also emphasized in this paper. The distribution of the number concentration spectrum of aerosol particles of urban, rural, desert and marine types is fitted by logarithmic normal distribution. The main conclusions are as follows: 1) Tianjin. The aerosol spectrum distribution in Xiamen area and Hefei area is described by Junge distribution and logarithmic normal distribution. The intermediate modes are lognormal distribution and the peak value center is 0.80. 0.86 渭 m and 0.54 渭 m, which accord with the characteristics of urban aerosol. The aerosol spectrum distribution in Xinjiang is described by Junge distribution.) in Xinjiang, Tianjin, Xiamen and Hefei, the real atmospheric aerosol refractive index (nr) is about 1.50. The imaginary part of refractive index is 0.010 0. 017 0. 008 and 0. 016. 3 respectively) in Tianjin area. The change trend of extinction coefficient and absorption coefficient with wavelength is the same in Hefei region and Xiamen area, but almost no change in long wave band. In Xinjiang region, the short-wave band extinction effect is obvious, but in the long-wave band is the absorption effect is obvious. 4) the city type aerosol, the countryside type aerosol. The distribution of numerical concentration spectrum of desert aerosol and marine aerosol is basically superposed by three-stage logarithmic normal distribution. The model radius of the intermediate model of urban aerosol is about 1 渭 m. Aerosols mainly have two fine-grained models. The radius of the intermediate model of marine aerosol is also around 1 渭 m, but mainly due to sea salt droplets. There is no coarse grain model in the Pacific Ocean. In summer, the concentration of coarse model is the highest in desert aerosol.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

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