Large-scale product of forest height using a new approach from spacborne repeat-pass sar interferometry and lidar

摘要

Spaceborne SAR interferometry (InSAR) has the potential of mapping the forest height on a global scale and a monthly/weekly basis, which can improve our understanding of the global carbon dynamics. In previous work, repeat-pass SAR interferometry from spaceborne sensors is utilized to create large-scale forest height maps based on a newly developed approach. This paper thus serves as a summary paper and also sheds light on the future directions with improved results. In particular, it will be shown that repeat-pass SAR interferometry is able to create a large-scale (11.6 million hectares) forest height mosaic product with RMSE ≤ 4 m for forest stands on the order of 6 hectares over both the flat and mountainous areas in New England, US through using the past and current spaceborne repeat-pass InSAR observations (i.e. JAXA's ALOS-1 and ALOS-2) combined with sparse airborne lidar training samples (44,000 hectares). Moreover, the results and performance of this approach can be remarkably improved with several enhancement techniques that can be easily satisfied with the use of future spaceborne repeat-pass InSAR and lidar missions (e.g. NASA-ISRO's NISAR and NASA's GEDI). The methodology described in this paper can be considered as a complimentary tool to the existing PolInSAR technique when single-pass full/dual-pol data are not available and/or the underlying topography is complicated.