热带人工林SAR散射组成及对遥感估测叶面积指数的影响

The Composition of Tropical Plantation Forest Microwave Backscattering and Its Impact on Estimating Leaf Area Index

基于RADARSATSAR数据,利用MIMICS(Michigan Microwave Canopy Scattering)模型模拟森林组分(冠层、树干层、地表)雷达后向散射,模拟研究表明在稀疏的人工林地区,地表层与森林冠层的直接散射是影响森林总的后向散射中最重要的两个因素。在同样的地表条件与森林环境假设下,阔叶林的模拟结果与影像的一致性要优于针叶林,针叶林由于受到地形起伏的影响,难以利用模型模拟森林的散射情况。同时,研究发现,利用森林郁闭度可以定量的表示森林冠层直接散射与总散射的相关关系,因而在一定的条件下得到冠层直接散射。最后,对该方法进行了简单的验证。

The study simulated microwave backscattering from all components of forests using MIMICS（ Michigan Microwave Canopy Scattering）Model and RADARSAT SAR data, including crown ,trunk and soil layer. The study concluded that, in sparse plantation forest area, the backscattering from direct crown and direct soil are both the most significant factors, and in the same premise, the consistence between the simulated data and the measured data of broadleaf forest was much better than that of conifer forest. For conifer forest, it was largely influenced by rugged terrain and it was difficult to simulate its microwave backscattering. Meanwhile, It was found that by using the forest closure parameter, the relationship between total and direct crown layer forest microwave backscattering could be determined and direct crown layer microwave backscattering could be quantitatively obtained. In the end, the paper validated the method.