Mapping Large-Scale Forest Height by Integrating Tandem-X and Multi-Source Remote Sensing Data: a Case Study of Spain

Acquiring high-resolution and accurate forest height is essential for estimating terrestrial carbon storage and detecting changes. Since 2010, TanDEM-X has obtained an unprecedented global interferometric SAR dataset and has been widely used to estimate forest height. However, its accuracy is limited due to insufficient observational information. Since September 2018, NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) has acquired global discrete surface elevation and forest canopy height, providing an excellent opportunity to improve the performance of TanDEM-X forest height estimation. Based on our previous research, this paper proposes some methods to estimate highresolution and large-scale forest height using these two missions combined with optical remote sensing data, and estimates forest height in Spain. As validated against LiDAR data, the RMSE of the estimated optimal average forest height ranges from 1.83 m to 3.70 m, at the resolution of onehectare forest stands.