A finite-volume solution with a bidirectional upwind difference scheme for the three-dimensional radiative transfer equation

作     者：Ishida, Haruma Asano, Shoji 

作者机构：Tohoku Univ Grad Sch Sci Ctr Atmospher & Ocean Studies Sendai Miyagi 980 Japan 

出 版 物：《JOURNAL OF THE ATMOSPHERIC SCIENCES》 (大气科学杂志)

年 卷 期：2007年第64卷第11期

页      面：4098-4112页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

主　　题：CLOUD HORIZONTAL INHOMOGENEITY SHAPED OPTICAL MEDIA MARINE STRATOCUMULUS ATMOSPHERES CLIMATE FLUX Regenerative Turboprop Engine RADIATION FIELD Marine Stratocumulus difference scheme Bidirectional Climate computational scheme atmosphere Linear equation finite volume method transfer equation radiance Monte Carlo technique Radiative transfer equation 

摘      要：A new calculation scheme is proposed for the explicitly discretized solution of the three-dimensional (3D) radiation transfer equation (RTE) for inhomogeneous atmospheres. To separate the independent variables involved in the 3D RTE approach, the spherical harmonic series expansion was used to discretize the terms, depending on the direction of the radiance, and the finite-volume method was applied to discretize the terms, depending on the spatial coordinates. A bidirectional upwind difference scheme, which is a specialized scheme for the discretization of the partial differential terms in the spherical harmonic-transformed RTE, was developed to make the equation determinate. The 3D RTE can be formulated as a simultaneous linear equation, which is expressed in the form of a vector-matrix equation with a sparse matrix. The successive overrelaxation method was applied to solve this equation. Radiative transfer calculations of the solar radiation in two-dimensional cloud models have shown that this method can properly simulate the radiation field in inhomogeneous clouds. A comparison of the results obtained using this method with those using the Monte Carlo method shows reasonable agreement for the upward flux, the total downward flux, and the intensities of radiance.