Estimation of leaf area index for Dendrocalamus giganteus based on sequential Gaussian conditional simulation
Leaf area index(LAI)is a crucial parameter in forest ecosystem studies that serves as a key indicator for assessing ecosystem development.This study utilized data from the ice,cloud,and land elevation satellite(ICESat-2)equipped with an advanced topographic laser altimeter system(ATLAS)in conjunction with Landsat 9 satellite imagery and terrain characteristics data.Data from 51 measured plots were incorporated,and the sequential Gaussian conditional simulation(SGCS)method was applied in tandem with machine learning models,including random forest(RF),gradient boosting regression tree(GBRT),support vector machine(SVM),and K-nearest neighbor(KNN),to estimate the LAI of Dendrocalamus giganteus on a regional scale.We found the following:(1)Pearson correlation analysis of the 46 extracted ICESat-2/ATLAS spot parameters revealed significant correlations of four specific parameters—best-fit segmented terrain height,interpolated terrain surface height,absolute mean canopy height,and solar altitude angle—with the measured LAI.(2)LAI estimated using the RF model,which integrated multi-source remote sensing data,demonstrated superior performance among the RF,GBRT,SVM,and KNN models,with a coefficient of determination(R2)of 0.901,a root mean square error(Erms)of 0.352,and a mean absolute error(Ema)of 0.289.(3)LAI within the study area derived from combined SGCS and RF models ranged from 2.089 to 2.493,with a mean value of 2.291.Regional-scale LAI estimation using ICESat-2/ATLAS high-density light spots offers distinct advantages.Incorporating auxiliary data,such as optical imagery and terrain factors,can significantly enhance model accuracy,and represents an efficient and cost-effective approach for regional-scale LAI estimations.We also introduce novel concepts for integrating ICESat-2/ATLAS data with other remote sensing imagery to estimate additional forest structural parameters.
ICESat-2/ATLASLandsat 9sequential Gaussian conditional simulationleaf area indexestimate
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