Mapping Forest Height from TanDEM-X Interferometric Coherence Data in Northwest Territories, Canada

• Published in: Canadian Journal of Remote Sensing
• Main Authors: Hao Chen, André Beaudoin, David A. Hill, Shane R. Cloude, Rob S. Skakun, Maryse Marchand
• Format: Article in Journal/Newspaper
• Language: English; French
• Published: Taylor & Francis Group 2019
• Subjects: Environmental sciences; GE1-350; Technology; T; Canada; Fort Simpson; Northwest Territories
• Online Access: https://doi.org/10.1080/07038992.2019.1604119; https://doaj.org/article/6b0dee4016ee4cc3bab071c2e03fdcad

In this paper, we demonstrate the feasibility of using TanDEM-X (TX) interferometric coherence data for mapping forest height with 25-m pixels across a study area near Fort Simpson, Northwest Territories (NWT), Canada. Our simplified RVOG model locally estimates forest height by combining an optimized estimation of TX interferometric coherence amplitude with the 20-m resolution Canadian Digital Elevation Model (CDEM) accounting for local slope variations. The initial map of TX height estimates provided R2 values of 0.78 and 0.88, mean errors (ME) of 1.66 m and 1.90 m, and root-mean-square errors (RMSE) of 2.7 m and 2.9 m when compared to independent height estimates derived from field plots and airborne LiDAR, respectively. We corrected the bias of TX height estimates using two variants of a LiDAR-based linear model. An application of three cover-specific linear adjustments provided the final TX height map with absolute ME ≤0.05 m and RMSE ≤2.09 m. The approach was tailored to poorly inventoried northern boreal regions through the use of archived TX data, the CDEM, a land cover map and airborne LiDAR transects. Our encouraging results support the perspective of wall-to-wall mapping of forest height across northern boreal forests in the NWT and beyond.