采用PROSAIL辐射传输模型建立毛竹林叶面积指数(LAI)-冠层反射率查找表,并结合Landsat TM卫星遥感数据,实现了毛竹林LAI的定量反演.结果表明:PROSAIL模型各输入参数的敏感性由高到低依次为LAI〉叶绿素含量(Cab)〉叶片结构参数(N)〉平均叶倾角(ALA)〉等效水厚度(Cw)〉干物质含量(Cm),并以LAI、Cab两个主要敏感因子用于构建毛竹林LAI-冠层反射率查找表;基于PROSAIL模型的毛竹林LAI遥感反演结果与实测LAI具有很好的一致性,二者相关系数为0.90,均方根误差和相关的均方根误差也较小,分别为0.58和13.0%,但也存在反演LAI平均值高于实际值的问题.
The PROSAIL canopy radiative transfer model was used to establish leaf area index (LAI) and canopy reflectance lookup-table for Moso bamboo forest. The combination of Landsat Thematic Mapper (TM) image and this model was then used to retrieve LAI. The results demonstrated that the sensitivity of the input parameters in the PROSAIL model decreased in order of LAIchlorophyll content (Cab) leaf structure parameters (N) mean leaf angle (ALA) equivalent water thickness (Cw) dry matter content (Cm). The most sensitive factors LAI and Cab were then used to construct the LAI-canopy reflectance lookup-table. The LAI estimates from the PROSAIL model had good agreement with the reference data, with the coefficient of determination (R2) reached 0.90. The root mean square error (RMSE) and relative RMSE were 0.58 and 13.0%, respectively. However, the mean LAI estimate was higher than the observed value.