Evaluation of Height Metrics and Above-Ground Biomass Density from GEDI and ICESat-2 Over Indian Tropical Dry Forests using Airborne LiDAR Data.

Autor: Rodda, Suraj Reddy, Nidamanuri, Rama Rao, Fararoda, Rakesh, Mayamanikandan, T., Rajashekar, Gopalakrishnan
Zdroj: Journal of the Indian Society of Remote Sensing; Apr2024, Vol. 52 Issue 4, p841-856, 16p
Abstrakt: The new-era space-borne LiDAR systems, viz. ICESat-2 and GEDI, offer new possibilities for mapping terrain and canopy heights through geophysical data products, viz ATL08 (ICESat-2) and L2A (GEDI). Additionally, GEDI provides an above-ground biomass density (AGBD) product (L4A) derived through parametric calibration of L2A metrics. Detailed comparisons of these data products among different forest types and other influencing factors (viz. acquisition parameters and ground conditions) are essential for continued improvement and broader use. In this study, we perform a detailed accuracy assessment of these data products over tropical dry deciduous forests in the Central Indian region during leaf-off and leaf-on seasons with the reference airborne LiDAR data. The GEDI L4A (AGBD) product is validated against the reference AGBD map derived from the field AGBD estimates and canopy height model from airborne LiDAR. Our results suggest that regardless of leaf condition, strong or power beams during nights from both systems (GEDI and ICESat-2) are highly capable of retrieving terrain height with RMSE 2.8–3.8 m and low bias of − 0.2 m to + 1.4 m. Nevertheless, GEDI canopy height retrievals were strongly linked to leaf availability with significant underestimations (bias > − 5.8 m) during the leaf-off season against a bias of ± 1 m during the leaf-on season. In contrast, strong night beams from ICESat-2 were found to retrieve canopy heights accurately with a bias of − 0.4 m and RMSE of 3.5 m during the leaf-off season. The GEDI-AGBD estimates were found to be substantially mismatched with the reference AGBD map with an overall RMSE of 46%. The atmospheric conditions and topographic slope strongly influenced the accuracy of both systems. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
Externí odkaz: