Polarization Of Scattering Light In The Atmosphere

The sky is polarized due to sunlight's scattering by particles and air molecules in the atmosphere. The sky polarization patterns consisted of different polarized skylight present us with the most conspicuous polarization information which can be used as an external compass. The celestial skylight polarization pattern is mainly determined by atmosphere particles, the location of the Sun and weather conditions. In the paper we concentrate upon analyzing the scattering mechanism, modeling theoretical celestial polarization patterns and making comparison between measured results and theoretical models. The skylight polarization information can be used to simulate insect navigation strategy, to enhance remote sensing ability, and to explore atmosphere optics parameters etc.This dissertation includes the following contents:(1) Mathematic laws on light essence and polarization are explained in detail. The physical characters of atmosphere and inside particles are listed for use in following sections. With those characters the celestial light radiation intensity patterns are displayed in the zenith-centred coordinate system.(2) Scattering light radiation of atmosphere particles such as gaseous molecules, aerosol, dust and water droplets are analyzed on the basis of Rayleigh scattering and Mie scattering. The scattering light's radiation and polarization distributing laws are summarized.(3) Celestial skylight polarization patterns are caculated with real-time atmosphere parameters according to the Rayleigh and Monte Carlo modeling of light transport theories. An algorithm for representing the theoretic skylight polarization pattern without distortion on 2D plane is proposed. With the algorithm, the comparison between theoretical models and measured results becomes simply and accurately.(4) An imaging polarimeter is constructed for skylight polarization detection. The skylight polarization patterns near zenith areas and neutral point are measured in the experiments. The limitation of therotical models are dignosed carefully by making comparision with measured results.