非球形气溶胶对近红外偏振辐射传输的影响及等效球形误差分析
Received:March 14, 2016  Revised:October 08, 2016  点此下载全文
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Author NameAffiliationE-mail
HU Shuai College of Meteorology and Oceanography, PLA University of Science and Technology hushuai2012@hotmail.com 
GAO Tai-Chang College of Meteorology and Oceanography, PLA University of Science and Technology gaotaichang2014@163.com 
LI Hao College of Meteorology and Oceanography, PLA University of Science and Technology lihao_pla@163.com 
CHENG Tian-Ji College of Meteorology and Oceanography, PLA University of Science and Technology  
CHEN Ming College of Meteorology and Oceanography, PLA University of Science and Technology 731225270@qq.com 
LIU Lei College of Meteorology and Oceanography, PLA University of Science and Technology  
ZHANG Ting College of Meteorology and Oceanography, PLA University of Science and Technology  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:气溶胶非球形性是影响气溶胶遥感及气候模拟精度的重要因素。为定量评估非球形气溶胶对偏振辐射传输的影响,基于T矩阵模型及自主开发的矢量辐射传输模式MACAR_VSPART,讨论了漫射光辐亮度及偏振辐亮度对粒子形状的敏感性,分析了气溶胶球形假设造成的漫射光模拟偏差,探讨了粒子形状对辐射通量密度的影响。结果表明,不同方向漫射光的辐亮度及偏振辐亮度对形状的敏感性不一致,且其形状敏感强度的空间分布呈现特定特征,该特征可为气溶胶遥感过程中有效观测数据的选取提供依据。等效球形假设可造成较大的漫射光模拟偏差,其中偏振辐亮度尤为显著,最大误差可达341.3%;天顶上行漫射光对粒子形状的敏感性远强于地面下行漫射光。等效球形假设造成的辐射通量密度模拟误差随有效半径增大而增加;当太阳入射角较小时,球形假设可能低估天顶上行辐射通量密度而高估地面下行辐射通量密度,随着太阳入射角增大,该特征正好相反。
中文关键词:非球形气溶胶  偏振辐射传输  形状敏感系数  等效Mie散射误差
 
An analysis on the impact of non-spherical aerosol on polarized radiative transfer in near-infrared band and its equivalent-sphere errors
Abstract:Abstract: Non-spherical aerosol is an important factor influencing aerosol remote sensing and climate simulation. In order to estimate the impact of non-spherical aerosol on polarized radiative transfer quantitatively, the sensitivity of radiance and polarized radiance to aerosol shape is analyzed for different particle effective radiuses, Aerosol Optical Depth (AOD) and solar zenith angles. In addition, the simulation errors due to the approximation that taking the non-spherical particles as sphere ones (called “equivalent Mie scattering errors”) are discussed. Considering the importance of fluxes for climate research, the influence of non-spherical aerosol on fluxes is analyzed as well. The simulation results show that, for radiance and polarized radiance, shape sensitivities are different at different directions, and the angular distributions of shape sensitivity coefficient are typical for specified solar zenith angles, which is helpful for the data selection of remote sensing process to avoid the influence of aerosol shape. Obvious simulation errors are caused by taking the non-spherical aerosol particles as sphere ones, especially for polarized radiance, where its maximum simulation error can reach 341.3%. The impact of shape on upwelling diffuse light at the top of atmosphere is much stronger than down-welling diffuse light at surface. The simulation error of fluxes due to spherical hypothesis becomes larger with increasing the effective radius. The up-welling fluxes tend to be underestimated by spherical hypothesis for small solar zenith angles, while the down-welling fluxes tend to be overestimated, the result is opposite for large solar zenith angles.
keywords:non-spherical aerosol, polarized radiative transfer, sensitivity coefficient of shape, equivalent Mie scattering error
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Copyright:《Journal of Infrared And Millimeter Waves》