大气气溶胶粒子数密度谱和折射率虚部的测量

介绍一种综合利用光学粒子计数器和能见度仪测量大气气溶胶折射率虚部的新方法。首先，使用光学粒子计数器测量出大气气溶胶粒子的数密度谱(待订正)，用能见度仪同步测量出水平能见度。然后，根据球形粒子的米氏(Mie)散射理论，通过分析气溶胶粒子的折射率虚部、分档半径、粒子数密度谱、消光系数和能见度之间的关系，对分档半径进行订正，得到折射率虚部和能见度之间的对应关系。结合同步测量的能见度，反演出大气气溶胶粒子的折射率虚部。最后，利用折射率虚部对光学粒子计数器数据进行订正，得到大气气溶胶粒子的数密度谱。

Measurements of Number Density Distribution and Imaginary Part of Refractive Index of Aerosol Particles

A new method is proposed for the measurement of imaginary part of refractive index n i of aerosol by using an optical particle counter (OPC) and a visibility meter (VM). The number density distribution of aerosol particle is measured by an OPC with nominal radii, and visibility is measured simultaneously with a VM. According to the Mie scattering theory, the different distributions can be obtained with different n i for the same set of data measured by OPC. Then, a curve of extinction coefficient can be calculated with n i from these distributions. Actual value of n i can be decided with the real extinction coefficient provided by visibility measurement. Finally, the actual number density distribution of aerosol particles is obtained from the OPC data and the decided n i.