摘要
太阳光入射与地表、大气相互作用,会在天空中出现较为稳定的天空偏振模式图,即以太阳为中心,天空中的偏振信号呈现一定的规律分布。影响天空偏振模式图的强度及形态主要由地表反射性质、空气分子散射性质及气溶胶光学性质共同影响。本研究利用矢量辐射传输模型,以海洋下垫面为例,在获取沙尘非球形与煤烟非球型气溶胶单次散射性质的基础上,模拟了不同气溶胶光学厚度情况下的全天空偏振模式图。结果表明,天空以太阳入射方向为中心呈现一个较为稳定的天空偏振模式图。沙尘型散射气溶胶光学厚度的增大会减弱该模式图的强度,而煤烟型吸收气溶胶光学厚度的增大会增大该模式图的强度。利用双模态(沙尘型与煤烟型混合)气溶胶模型,系统分析不同气溶胶比例情况下的天空偏振模式图,结果表明全天空偏振模式图的基本模态依旧存在,但是其强度受气溶胶模型与光学厚度双重影响。因此在利用全天空偏振模式图进行气溶胶光学性质反演时需要注意气溶胶模态信息的选择。
This paper discusses the status of full sky polarization pattern and the major factors affecting its strength. These factors are Aerosol Optical Depth （AOD） and aerosol models （described by the single scattering properties of aerosol particles）. The different results of AOD and aerosol models are demonstrated. A relatively stable and regular sky polarization pattern is suggested to exist in the sky centering the position of the sun through the comprehensive results of incident solar light with underlying surface and atmosphere. This complex process can be described and calculated by vector radiative transfer models with the output of polarization components. The full sky polarization signals exhibit a certain regular distribution in the sky. The strength and pattern of full sky polarization are affected by the combination of surface reflective properties （including polarized reflectance and bidirectional reflectance）, atmosphere molecule-scattering properties, and aerosol optical properties. This study simulated different full sky polarization patterns under various AOD conditions based on vector radiative transfer models. For example, the underlying surface is assumed to be an ocean surface. The land surface is omitted in this study because its basic pattern is similar to that of the ocean surface. The single scattering properties of dust nonspherical and soot nonspherical aerosol particles were calculated using a TMatrix-Geo model. Phase functions and other single scattering properties were then obtained as the basic inputs of vector radiative transfer model. Results demonstrated a relatively stable sky polarization pattern centering the direction of incident solar light. However, different effects were observed between dust and soot aerosol on full sky polarization pattern. The increase in dust-scattering AOD weakens the pattern of sky polarization from a maximum degree of polarization of 50% to less than 30%. Meanwhile, an increase in soot-absorbing AOD strengthens the pattern of sky polarizatio
作者
陈伟
李延飞
吴太夏
关桂霞
CHEN Wei;LI Yanfei;WU Taixia;GUAN Guixia(College of Geoscience and Surveying Engineering,China University of Mining ＆Technology（Beijing）Beijing 100083,China;Beijing Key Laboratory of Spatial Information Itegration and 3S Application,Peking University,Beijing 100871,China;Institute of Remote Sensing and GIS,Peking University,Beijing 100871,China;School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China;Information Engineering College,Capital Normal University,Beijing 100048,China)
出处
《遥感学报》
EI
CSCD
北大核心
2018年第6期989-995,共7页
NATIONAL REMOTE SENSING BULLETIN
基金
国家自然科学基金(编号：41701391)
国家高技术研究发展计划(编号：2008AA121806)
关键词
偏振
偏振场
气溶胶
偏振模式图
polarization
polarization field
aerosol
sky polarization pattern
