植被二向性反射统一模型研究

项目名称： 植被二向性反射统一模型研究

项目编号： No.41271346

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 范闻捷

作者单位： 北京大学

项目金额： 80万元

中文摘要： 面对全球变化的严峻挑战，就千差万别的植被类型而言，只有建立了可靠的植被BRDF统一模型，才有可能找到可行的反演方法，提供全球意义上的可靠的植被参数产品。本研究将抛弃连续植被-辐射传输模型，离散植被-几何光学模型的传统BRDF建模观念，将离散植被特性视为叶簇在不同尺度下群聚方式，由此将各类植被统一起来。基于不同植被二向性反射特性的共性，从理论分析着手，建立一个有明确物理意义，具有解析形式的BRDF统一模型。同时建立能准确描述土壤-冠层间多次散射的，且易于反演的多次散射模型。力图使复杂的二向性反射的表达变得简单明了，并以LAI和聚集指数反演为例研究不同植被生物参数的反演策略与方法，以适应全球植被生物参数监测之需要。

中文关键词： 植被BRDF；统一模型；聚集指数；太阳直射与天空漫射辐照度比例；再碰撞概率

英文摘要： Faced with severe challenges from global changes, only establishing reliable vegetation BRDF unified models, can we find feasible retrieval methods and provide reliable global products of vegetation parameters for different vegetation types. In this study, we abandon the traditional modeling ideas of radiative transfer models for continuous vegetation and geometry optical model for discrete vegetation. Therefore, different types of vegetation are unified, considering discrete vegetation as clumped leaf clusters at different scales . Based on the common character of bidirectional reflectance of different canopies, we start from the theories and analysis and establish a BRDF unified model with definite physical meaning and analytical form. At the same time, a multiple scattering model is set up, which can accurately describe the multiple scattering between soil and canopies and is easy for retrieval. Our purpose is making complex bidirectional reflectance simple and clear. Then taking LAI and clumping index retrieval as an example，retrieval strategies and methods of different vegetation parameters will be studied. The scaling effects of remote sensed vegetation parameters can also be re-analyzed to adapt the needs of the global vegetation biological parameters monitoring.

英文关键词： vegetation BRDF；unified model；Clumping Index；proportion of direct solar radiation and diffuse；recollision probability