讨论使用蒙特卡罗方法模拟非同温水平均匀冠层热辐射的方向性特征。模拟中,水平均匀冠层用叶面积指数、叶倾角分布函数和叶面积指数廓线描述,设土壤和叶片均为朗伯体,蒙特卡罗模拟基于光子在非同温冠层中的传输过程,并且考虑了光子在冠层内的多次散射。现有的计算机模拟结果验证了李小文等提出的非同温地表有效比辐射率概念模型。

A model for thermal IR exitance of a plant canopy based on Monte Carlo simulation of photon transport isdeveloped. The canopy is defined by leaf area index, leaf angle distribution, and leaf area profile. Canopy is dividedinto some layers by layer density. Every layer can have itself leaf area index and leaf angle distribution. Soil and leaf areassumed as Lambertian source, and they also do Lambertian response for photon scattering. The Monte Carlosimulation included mutli-scattering of photon. The LSF conceptual model of effective emissivity for non-isothermalsurface is validated. Simulation showed that the multi-scattering between components and component temperaturedifferences of a canopy are two key factors for directional thermal emission of the canopy. Component temperaturedifferences influence effective emissivity weakly, thus the effect can be ignored.