应用4-scale模型对人工针叶林郁闭度的反演  

Artificial Coniferous Forest Remote Sensing by Using Geometric Optical Model

作　　者：智献坡 李明泽[1] 于颖[2] 江蕾 Zhi Xianpo;Li Mingze;Yu Ying;Jiang Lei(Northeast Forestry University,Harbin 150040,P.R.China)

机构地区：[1]东北林业大学林学院,哈尔滨150040 [2]东北林业大学,哈尔滨150040

出　　处：《东北林业大学学报》2020年第12期5-11,共7页Journal of Northeast Forestry University

基　　金：国家重点研发计划课题(2017YFD0600902-5)。

摘　　要：利用4-scale模型模拟不同叶面积指数、不同样地树木结构参数下的背景可视概率、冠层反射率,建立查找表。利用遥感数据,以像元尺度ILA值作为控制变量,根据冠层反射率数据查找对应ILA下的背景可视概率,进而反演出冠层郁闭度。最后采用鱼眼相机与样点法实测的郁闭度做模型的检验。结果表明:4-scale模型能很好地反演人工针叶林冠层郁闭度,与其他3种测量郁闭度方法相比,4-scale模型反演郁闭度与鱼眼照片提取的冠层郁闭度有很好的线性关系,决定系数R^2=0.628、均方根误差ERMS=0.0476,与样点法、样线法计算的郁闭度R^2与ERMS分别为0.5591、0.0518和0.5395、0.0529。考虑树干对鱼眼照片提取冠层郁闭度的影响后R^2为0.6847;对于人工落叶松林,R^2由0.4226提升到0.6153;对于人工油松林,R^2由0.7646变为0.7561。4-scale模型针能很好的反演人工针叶林冠层郁闭度,同时也证明4-scale模型反演冠层郁闭度与鱼眼照片提取的冠层郁闭度之间存在良好的关系。Taking the artificial coniferous forest in Wangyedian Experimental Forest Farm,Chifeng City,Inner Mongolia as the study area,the effective method of obtaining canopy density by 4-scale model combined with remote sensing image was discussed,which provided reference and basis for retrieving canopy density by mechanism model.The 4-scale model was used to simulate the background visual probability and canopy reflectance under different leaf area index and different tree structure parameters,and a lookup table was established.With remote sensing data and pixel-scale I LA values as control variables,the background visibility probability under corresponding I LA was found according to canopy reflectance data,and then forest canopy density was retrieved.Finally,the canopy density measured by fish-eye camera and sample point method is used to test the model.The canopy density of artificial coniferous forest could be retrieved well by 4-scale model.Compared with the other three canopy density measurement methods,the canopy density retrieved by 4-scale model had a good linear relationship with the canopy density extracted from fish-eye photos,with decision coefficient R^2=0.628,root mean square error ERMS=0.0476.The canopy densities R^2 and E RMS calculated by point method and line method were 0.5591,0.0518 and 0.5395,0.0529,respectively.Considering the influence of tree trunk on the canopy density of fish-eye photograph,R^2 was 0.6847.For artificial larch forest,R^2 increased from 0.4226 to 0.6153.For artificial Pinustabulaeformis forest,R 2 changed from 0.7646 to 0.7561.The canopy density of artificial coniferous forest can be retrieved by 4-scale model,and the relationship between canopy density retrieved by 4-scale model and canopy density extracted from fish-eye photographs is also proved.

关 键 词：人工针叶林 冠层郁闭度 样点法 样线法 鱼眼照片 4-scale模型 

分 类 号：S758.1[农业科学—森林经理学]