海洋气溶胶多光谱偏振特性研究

为提高海洋气溶胶的反演精度，定量研究了气溶胶在可见近红外波段的多光谱偏振辐射特性。首先建立了合理的海洋气溶胶及海面模型，基于逐次散射法准确模拟了光在气溶胶中及大气—海洋交界面处的矢量辐射传输过程，接着从光谱角度定量分析了典型波段处的反射率和偏振反射率，在此基础上提出了海洋气溶胶偏振辐射的光谱分布模型，并用卫星数据对模型进行验证，最后研究了气溶胶光学厚度、观测角度、海水叶绿素a浓度和海面风速对气溶胶多光谱偏振辐射的影响。研究表明，在可见近红外波段不考虑大气吸收和耀斑效应时，气溶胶偏振辐射的光谱变化符合幂函数模型;在不同波段处，海洋气溶胶的偏振辐射受海水叶绿素a浓度和海面风速的影响不同;海洋气溶胶的多光谱偏振辐射信息有效体现了气溶胶的自身特性，且与反射率相比，偏振反射率随各因素的变化存在更明显的谱段差异性。因此，可以运用气溶胶的多光谱偏振信息反演海洋气溶胶参数，多光谱探测的加入对提高气溶胶反演精度具有重要意义。

Multi-Spectral Polarized Properties of Ocean Aerosol

In order to improve the retrieval accuracy of ocean aerosol ,quantitative study was carried out in terms of the multi-spectral polarized properties of the aerosol in visible and near-infrared wavebands.Firstly,an aerosol model and a sea surface model were built.And the vector radiative transfer procedure of light in aerosol and atmosphere-ocean interface was simulated
accurately based on the successive order of scattering method.Then from the perspective of the spectrum,the reflectance and polarized reflectance at the top of atmosphere in typical wavebands were quantitatively analyzed.Based on this,the spectrum dis-tribution model of ocean aerosol polarized radiation was presented.And the model was validated with satellite data.Lastly,the influences of aerosol optical depth,viewing angle,chlorophyll a concentration and wind speed on multi-spectral polarized radia-tion of ocean aerosol were studied.The study shows that the changes of aerosol multi-spectral polarized radiation with wave-length can be best described with power function model when ignoring the absorbtion of atmosphere and solar flare effect in visi-ble and near-infrared wavebands.This phenomenon can be caused by Rayleigh scattering and Mie scattering.The influences of chlorophyll a concentration and wind speed on multi-spectral polarized radiation of ocean aerosol emerge as very different in dif-ferent wavebands.Specifically,the influences of chlorophyll a concentration on reflectance and polarized reflectance both can be neglected in near-infrared waveband.But in visible waveband,the influence on the reflectance must not be neglected any longer. Due to the increasement of the wind speed,the reflectance and the polarized reflectance increased significantly.But there are differences in the increases in different wavebands.The multi-spectral polarized radiative information of ocean aerosol can embod-y its own charactersitics effectively.And furthermore,the change of polarized reflectance with each factor has more obvious differences in different wavebands compared with reflectance.As a result,the multi-spectral polarized information of ocean aero-sol can be used to retrieve the parameters of the aerosol over the ocean.The achievement of multi-spectral information has great significance for improving the retrieval accuracy of the ocean aerosol.