利用Landsat TM遥感影像和同期的叶面积指数(LAI)观测数据生成了江西省泰和县30 m LAI图。据此比较了基于4-尺度几何光学模型反演的LAI和MODIS LAI的质量。结果表明,基于4-尺度几何光学模型反演的LAI和MODIS LAI存在着明显的差异,两者相关的R2为0.312 5,在1 km尺度两者的平均值比TM LAI的平均值分别偏低14.0%和11.7%;在LAI低值区,MODIS LAI偏高,基于4-尺度几何光学模型反演的LAI偏低,而在LAI的高值区(LAI〉6.0),MODIS LAI和基于4-尺度几何光学模型反演的LAI都偏低,MODIS LAI的偏低尤为明显,达31.4%。
Based on field measurements of forest leaf area index(LAI) and concurrent landsat TM data,a high resolution map of forest LAI for Taihe County,Jiangxi Province was produced.Based on this map,the quality of LAI inversed using the method based on 4-scale geometrical optical model and MODIS LAI was assessed.It was found that noticeable difference exists between MODIS LAI and LAI inversed using the method based on the 4-scale model,with a R2 value of 0.312 5.The means of LAI inversed using the method based on the 4-scale model and MODIS LAI are 14.0% and 11.7% lower than that of TM LAI at 1 km resolution,respectively.In areas with low LAI values,MODIS LAI is higher than TM LAI while LAI inversed using the method based on the 4-scale model is lower than TM LAI.In areas with high LAI values(LAI6.0),both MODIS LAI and LAI inversed using the method based on the 4-scale model are lower than TM LAI.Especially,MODIS LAI is 34.1% lower compared with TM LAI.