一种改进的辐射传输计算方法

精确、快速计算辐射传输一直是大气辐射学中的一个重要研究课题。我们在Knut Stamnes的离散纵标法（1988）1]的基础之上,提出了一种辐射传输四流近似计算方法。该算法可以得到一个解析解,并且通过作数值计算,可以看到本算法的计算精度是令人满意的。

Improved Four-stream Approximation Method for Solar Radiative Transfer

It is important to find a precise and fast algorithm for solar radiative transfer in the atmosphere . In this paper, we present, based on Stamnes's discrete-ordinate-method, an analytical four-stream approximation algorithm. In our algorithm, we separate out the singly scattered radiation and apply the normal four-stream approximation of Stamnes's discrete-ordinate-method to the multiply scattered radiation alone. The singly scattered irradiance is computed analytically without approximation, preserving more of the angular dependence in the radiance than other four-stream approximation solutions. Because of the analytical form of the derived solution, the computational time of our algorithm is less than that of the rigorous numerical algorithm. Numerical experiments show that the accuracy of the algorithm is satisfactory. Particularly in the case the absorption is dominant, the error of the algorithm is very small.