森林冠层BRF分布模拟

BRF distribution of forest canopy

森林的组成、结构及其动态变化一直是林业遥感研究的一个热点,森林冠层结构对太阳辐射能量分布以及植被冠层的生物物理参数有非常重要的影响.针对计算机模拟模型难以用于大尺度的森林场景模拟和森林参数反演等问题,基于针叶枝简化的方法,分析了利用辐射度模型(RGM)进行森林冠反射特性研究,将森林生长模型(ZELIG)和L-系统结合进行三维虚拟森林场景建模,进而利用RGM模型模拟它们在可见光和近红外波段的双向反射率因子(BRF),并将模拟光谱和长白山研究区的多角度CHRIS(the compact high resolution imaging spectrometer)数据进行了比较.结果表明:模型模拟的5个角度光谱和图像光谱基本吻合.这将对利用RGM模型和多角度CHRIS数据进行森林冠层结构参数的反演具有重要的参考价值.

The study of forest composition,structure and dynamic changes in the forestry remote sensing has been a hot issue.Forest canopy structure has an important effect on the energy distribution of solar radiation and the biophysical parameters of vegetation canopies.It is difficult for the computer simulation method to study radiation regime and estimate the structural parameters of forest canopies at large-scale.Simplified coniferous model,Radiosity-graphics combined model（RGM） was applied to investigate the radiance distribution of forest canopy in this study.Combined the forest growth model ZELIG and L-systems to render 3D forest scenarios,and the RGM model was used to calculate bidirectional reflectance factor（BRF） at visible and near-infrared regions.Finally,the spectra was compared between the simulated by RGM model and multi-angle the compact high resolution imaging spectrometer（CHRIS） data in the experimental field of Changbai mountain.The results show that they were both agreed well.It has an important value for inversion of the structure parameters of forest canopy with RGM model and multi-angle CHRIS data.