Research On Atmospheric Polarization Pattern And Its Influencing Factors Of Different Weather Conditions

Sunlight is non-polarized natural light before it enters the Earth’s atmosphere. After entering the atmosphere, it becomes partially polarized light caused by scattering of atmospheric molecules、cloud、aerosol and surface reflection, which constitutes the skylight polarization mode. The distribution of skylight polarization pattern is of great importance in remote sensing, polarization navigation, and many other areas. In this paper, the method of modeling the atmospheric polarization pattern and its influencing factors are presented. The content of this paper is conducive for the application of polarized light in actual atmosphere.First, we analysis the reasons for the formation of the skylight polarization mode and its influencing factors on the basis of the theory of the atmospheric scattering. We focus on the atmospheric radiation vector transmission, and choose the adding-doubling method to solve the vector radiative transfer equation. The method of modeling skylight polarization pattern based on RT3is presented combined with the actual atmospheric and aerosol model.Secondly, by the skylight polarization data processing software, we simulate the skylight polarization mode respectively under Rayleigh scattering atmosphere and actual atmospheric. The former can verify the correctness of the method of modeling skylight polarization at this article, the latter can analysis the distribution of skylight polarization under the weather conditions of sunny, cloudy and haze.Finally, using the skylight polarization measuring system set up by ourselves, a lot of experiments were done under different weather conditions. At last, we acquire the impact of different wavelengths and different aerosol optical depth on skylight polarization.The results show that:As the increase of aerosol optical depth, the degree of polarization (DOP) will decrease, especially more significantly reduction for the longer wavelength; The DOP decreases with the increase of surface albedo, and the surface albedo has no influence on the distribution of skylight polarization pattern; As the wavelength increase, the DOP increases at sunny day, but the DOP decrease at cloudy or haze, so the longer wavelength should be chose at sunny day, but shorter wavelength at cloudy for polarized light testing and research.