Canadian Forest Service Publications

Mapping Forest Height from TanDEM-X Interferometric Coherence Data in Northwest Territories, Canada. 2019. Chen, H; Beaudoin, A.; Hill, D.A.; Cloude, S.R.; Skakun, R.S; Marchand, M. Canadian Journal of Remote Sensing, 45:3-4, 290-307.

Year: 2019

Issued by: Pacific Forestry Centre

Catalog ID: 40128

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1080/07038992.2019.1604119

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Abstract

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.

Plain Language Summary

In this paper, we assess the potential of using spaceborne radar interferometric coherence data from the German TanDEM-X system for the challenging estimation of forest canopy height of the sparse, short and slow-growing boreal forests at the northern extent of treed areas in Northwest Territories (NWT) of Canada. The study was carried out over a representative pilot region near Fort Simpson in NWT. Our algorithm locally estimates forest canopy heights by combining the radar interferometric coherence amplitude with a reference digital elevation model (DEM). The accuracy assessment of the derived TanDEM-X canopy height product was performed against the stand height measurements from a network of independent ground plots, as well as from the stand height measurements derived from an airborne LIDAR canopy height model (CHM). Our study results demonstrated that the TanDEM-X interferometric coherence data worked well for the estimation of the forest canopy heights over the high latitude sparse and low boreal forests in this pilot region, which could be used to provide an important baseline reference product for future space-borne LIDAR/radar height measurement campaigns in NWT.