三维辐射传输模型LESS原理及其应用

三维辐射传输模型能够准确地刻画太阳辐射与异质地表之间的相互作用，近年来已成为定量遥感建模与反演研究中的重要工具。LESS模型是基于光线追踪的三维真实冠层辐射传输模型，充分利用了光线追踪的前向追踪模式模拟能量平衡问题以及后向追踪模式模拟大尺度(公里级)遥感影像，从而实现在同一模型中多种遥感数据的模拟。目前，LESS模型可以模拟多角度反射率、多/高光谱影像、鱼眼相机、复杂地形区上下行短波辐射、冠层分层FPAR等数据，可以为验证物理模型、发展参数化模型以及训练神经网络模型等提供更为可靠的模拟数据集。本文主要介绍了LESS模型的基本原理和典型的应用。LESS模型可以从www.lessrt.org网站下载。

Principles and Applications of the 3D Radiative Transfer Model LESS

Three-dimensional (3D) radiative transfer model can accurately describe the interactions between solar radiation and heterogeneous land surfaces. Recently, it has become an important tool for quantitative remote sensing studies. LESS is a ray-tracing based 3D radiative transfer model, which take full advantage of the forward ray-tracing techniques for simulating radiative budget and backward ray-tracing for simulating large-scale images, which makes it possible to simulate various remote sensing data in a single model. Currently, LESS can simulate multi-angle Bidirectional Reflectance Factor (BRF), multi-spectral/high-spectral images, fish-eye cameras, upwelling/downwelling shortwave radiation in rugged terrains and layered FPAR, etc. This simulated dataset can be used for validating physical modes, developing parameterized models, as well as training neural networks. This paper presents the fundamentals of LESS and its applications. LESS can be downloaded from www.lessrt.org.