蒙特卡罗模拟大气颗粒物粒子偏振特性研究

Polarization properties of atmospheric particulate matter based on Monte Carlo simulation

针对传统雾霾监测方法周期长,成本高的缺点,基于蒙特卡罗算法模拟了大气颗粒物粒子的偏振特性,进而来探索雾霾监测新方法。通过蒙特卡罗算法对大气颗粒物光散射过程进行模拟研究,首先采用Stokes参量和穆勒矩阵来构建光子传输与大气颗粒物介质偏振特性的模型,然后模拟研究入射光偏振态、波长以及粒子中值半径对偏振光在浑浊大气传输过程中的影响,最后统计不同角度的出射光子偏振信息。实验结果表明空气动力学直径在0.01μm-2.5μm(PM2.5)的大气可吸入颗粒物经过偏振光散射后出射光表现出明显偏振特性,且线偏振度随散射角出现驼峰型变化。基于这一模拟结果为后续利用偏振特性来监测雾霾污染提供了新的思路。

According to the long period and high cost of traditional method in monitoring the fog and haze, this paper explored a new method of haze monitoring with polarization characteristics of atmospheric particulate matter based on the Monte Carlo simulation. The method simulated the light scattering process of atmospheric particles by Monte Carlo algorithm. Firstly the Stokes parameters and the Muller matrix were used to construct polarization model with the photon propagation and atmospheric particulate matter medium. Then simulation study on the effect on the polarization state of incident light, the wavelength and the particle median radius of polarized light transmission in turbid atmosphere. Finally, the polarization information of the emitted photons at different angles was calculated. The experimental results show that the aerodynamic diameter of 0. 01μm-2. 5μm （PM2. 5 ） of atmospheric particulate matter after polarized light scattering has obvious polarization characteristics, and the degree of linear polarization undergo hump type change with the scattering angle. Based on the simulation results, it provides a new way to monitor the haze pollution by using polarization characteristics.