为解决目前临边遥感大气辐射传输模型存在计算光谱窄和计算速度慢等问题,基于HITRAN2008数据库、带模式算法和临边辐射传输方程建立了0.2—20 μm波段大气临边辐射传输的宽光谱快速计算模型FALTRAN.建立了含有散射辐射和热辐射的临边辐射传输方程,并依据临边几何特征提出了一种基于有限差分的半球辐射累加HRA解算方法.利用FALTRAN计算分析了几个常用的遥感波段内典型大气条件和切向高度时大气的临边辐射特性,并定量分析了左、右半球辐射对总辐射的贡献情况.模型校验结果表明,FALTRAN与CDI模型的计算结果相对差异在2%以内,并与MIPAS的测量结果符合很好,验证了FALTRAN在临边遥感中大气传输计算的可靠性.

We proposed a wide spectrum and rapid calculation model FALTRAN (Fast Atmospheric Limb TRANsmission), to solve the problems of current radiative transfer model in limb remote sensing. In FALTRAN: (1) Band model algorithm was employed and the molecular spectroscopy database was based on HITRAN2008. (2) Limb radiative transfer equation consists of scattering and thermal radiation was established, and according to the limb geometry characteristic, a Hemisphere Radiation Adding (HRA) approach based on finite difference method was proposed to solve it. We investigated the atmospheric limb radiations under typical atmospheric modes in several commonly used remote sensing bands. Moreover, radiation contribution by two hemispheres was quantitative analyzed as well. Validation results show that the relative differences between FALTRAN and Combining Differential-Integral (CDI) model are within 2%, and calculation results by FALTRAN have good agreement with Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements. FALTRAN is proven to be reliable in the limb radiative transfer calculation.