非球形火星沙尘粒子的光谱散射特性研究

Spectral Scattering Characteristic of Non-spherical Mars Dust Particles

针对复杂的火星大气环境,基于T-matrix理论,对三种非球形火星沙尘粒子的散射特性进行了研究,计算了服从对数正态分布的非球形火星沙尘粒子的散射特性,分别在有沙尘暴和无沙尘暴两种条件下,分析非球形火星沙尘粒子的传输衰减和透射率随粒子数浓度、波长以及高度的变化趋势,并与球形粒子进行对比.结果表明:非球形与球形粒子的消光效率因子和散射效率因子存在较大差异,两者之间的最大差值分别为1.7868和1.7619,而切比雪夫粒子的散射特性与球形粒子最接近;当入射波长为0.55μm时,火星上沙尘粒子群整体的散射主要集中在前向40°以内,且非球形与球形粒子在前向60°以内散射强度基本相等,大于60°时非球形的散射强度比球形粒子高;非球形火星沙尘粒子的传输衰减和透射率(随波长、粒子数浓度和高度)的变化趋势与球形的基本一致,且其尺寸的比值越接近于1,传输衰减和透射率越接近于球形粒子的值.

Aiming at the complex atmosphere environment on Mars,using the T-matrix theory,the scattering characteristics of three kinds of Mars dust particles with non-spherical shape were studied.Then the scattering characteristics of non-spherical Mars dust particles with lognormal distribution were calculated,and under the conditions of sandstorm and no sandstorm,the variation trend of attenuation coefficient and transmittance of non-spherical Mars dust particles with particle number concentration,wavelength and height was analyzed,and compared with spherical particles.The results show that the extinction efficiency factor and scattering efficiency factor of non-spherical and spherical particles are quite different,and the difference between them is as large as 1.7868 and 1.7619.The scattering characteristic of chebyshev particles is the closest to that of spherical particles.When the incident wavelength is 0.55μm,the overall scattering of dust particle swarm on Mars is mainly concentrated within 40°forward direction,and the scattering intensity of non-spherical and spherical particles are basically equal within 60°forward direction.When the scattering intensity is larger than 60°,the non-spherical particles have higher scattering intensity than spherical particles.The attenuation coefficient and transmission of non-spherical Mars dust particles(with wavelength,particle concentration,and height)are basically consistent with the spherical particles,and when the size ratio is closer to 1,its attenuation coefficient and transmission coefficient are closer to the value of spherical particles.