天空偏振光时域分布稳定性的实验研究

Experimental Research on the Stability of Skylight Polarization Pattern in Time Domain

太阳光在穿过大气层时与大气粒子发生散射作用,形成了稳定的偏振光分布模式,与太阳的位置、观测地点的位置以及不同的大气介质等因素有关。瑞利散射模型描述了偏振光在大气中的分布模式,被广泛的用于研究偏振光与太阳的信息传递关系。本文研究基于瑞利散射模型的天空偏振光时域分布稳定性,设计了一个由偏振图像采集系统和方位对准系统组成的实验平台,实现对天空偏振光分布的长时间测量,解算各时刻的太阳方位角和太阳高度角。以天文学年历计算值为基准,得到太阳方位角误差1.34°(1σ)和太阳高度角误差-2.28°(1σ)作为稳定性参数,结果表明天空偏振光时域分布具有较强的稳定性。本实验拓展学生对天空偏振光和大气散射的认识,激发学生兴趣和创新的精神。

Plenty of polarized light emerges from scattering by particles and air molecules during the process of atmospheric transmission of sunlight,forming a stable skylight polarization pattern,which is mainly determined by the solar position,the observation site and the atmosphere particles.Rayleigh scattering model represents the relationship polarized light distribution in the sky with the solar position.The stability of skylight polarization pattern in time domain based on Rayleigh scattering model is studied.An experimental platform consists of polarizing image acquisition system and azimuth alignment system is designed to measure the skylight polarization pattern.Then the solar azimuth and the solar elevation angle are calculated using polarizing images.Compared to the calculated values of the astronomical almanac,the solar azimuth error is 1.34°（1 σ ）and the solar elevation angle error is -2.28°（1 σ ）and the two errors are used as the stability parameters.The results indicate that the skylight polarization pattern in time domain has a strong stability.This experiment not only increase students’ understanding of sky polarized light and atmospheric scattering,but also stimulate interest and innovation.