大气折射对可见近红外波段辐射传输的影响分析  

Analysis on Impact of Atmospheric Refraction on Radiative Transfer Process at Visible and Infrared Band

作　　者：胡帅[1] 高太长[1] 李浩[1] 程天际 刘磊[1] 张婷[1] 黄威[1] 江诗阳 代中华[1] 

机构地区：[1]解放军理工大学气象海洋学院,江苏南京211101

出　　处：《光学学报》2016年第6期37-53,共17页Acta Optica Sinica

基　　金：国家自然科学基金(41575025;41575024)

摘　　要：为定量分析大气折射对辐射传输的影响,建立了矢量辐射传输模型(VSPART),讨论了大气折射对漫射光Stokes矢量及辐射通量密度的影响。在模型中,采用射线追踪法实现了大气折射过程的参数化,基于矩阵算法实现了辐射传输方程的求解;将VSPART模拟结果与文献值及SPDISORT、DISORT、RT3/PolRadtran和MYSTIC的模拟结果进行了对比,验证了模型间的一致性;在纯瑞利散射大气及含气溶胶大气条件下,分析了大气折射对地面下行辐射和天顶上行辐射漫射光Stokes矢量的影响,讨论了大气折射效应随太阳天顶角的变化。结果表明,太阳天顶角为86°时,在瑞利散射条件下,由大气折射造成的漫射光(波长0.35μm)I、Q和U分量的相对偏差可达9.2%、10.2%和11.3%,辐射通量密度的相对偏差可达5.3%。对于地面下行辐射,大气折射的影响总体随天顶角增大而增强,天顶上行辐射则反之。大气折射对地面下行漫射辐射的影响强于天顶上行辐射。随着气溶胶光学厚度的增加,大气折射效应显著增强;煤烟气溶胶条件下,大气折射的影响强于矿质型及海盐型气溶胶情形。当太阳天顶角大于70°时,大气折射的影响迅速增强,此时有必要在辐射传输模拟过程中考虑大气折射效应。In order to quantitatively discuss the influence of atmospheric refraction on radiative transfer process,a vector radiative transfer model（VSPART）is established and the atmospheric refraction impact on diffuse light＇s Stokes vectors and radiative flux density is discussed.In this model,the atmospheric refraction parametric process is simulated by using the ray-tracing method,and the radiative transfer equation is solved by using the matrix algorithm.The simulated results of VSPART agrees with literature results and classical radiative models such as SPDISORT（spherical discrete ordinate method）,DISORT（discrete ordinate method）,RT3/PolRadtran and MYSTIC（Monte Carlo code for the physically correct tracing of photons in cloudy atmospheres）.The impact of atmospheric refraction on the Stokes vectors of down-welling diffuse light at surface（DLS）and up-welling diffuse light at the top of atmosphere（ULT）is analyzed for Rayleigh scattering atmosphere and atmosphere with aerosol.Besides,the variation of the atmospheric refraction effect with the solar zenith angle is analyzed as well.Simulation results show that the relative deviations of the diffuse light＇s I,Q and U components due to refraction achieve9.2%,10.2%and 11.3%,and the relative deviation of radiant flux density approaches 5.3% when the solar zenith angle is 86°in the Rayleigh scattering atmosphere.For DLS,the impact of refraction is enhanced with the increasing of observing zenith angle,while for ULT,the fact is opposite.On the whole,the influence of atmospheric refraction on DLS is stronger than that on ULT.With the increase of aerosol optical thickness,the atmospheric refraction effect is gradually enhanced,and the influence of the atmospheric refraction for soot aerosol is much stronger than that for mineral dust and sea salt.When the solar zenith angle is larger than 70°,the impact of atmospheric refraction increases rapidly,and it is necessary to consider the atmospheric refraction process when simulating the radiative transfer

关 键 词：大气光学 折射效应 Stokes矢量 射线追踪法 矢量辐射传输 

分 类 号：P426.31[天文地球—大气科学及气象学]