Forest Height Estimation Using a Single-Pass Airborne L-Band Polarimetric and Interferometric SAR System and Tomographic Techniques

Yue Huang,Qiaoping Zhang,Laurent Ferro-Famil

doi:10.3390/rs13030487

Abstract

This paper addresses forest height estimation for boreal forests at the test site of Edson in Alberta, Canada, using dual-baseline PolInSAR dataset measured by Intermap’s single-pass system. This particular dataset is acquired by using both ping-pong and non-ping-pong modes, which permit forming a dual-baseline TomoSAR configuration, i.e., an extreme configuration for tomographic processing. A tomographic approach, based on polarimetric Capon and MUSIC estimators, is proposed to estimate the elevation of tree top and of underlying ground, and hence forest height is estimated. The resulting forest DTM and DSM over the test site are validated against LiDAR-derived estimates, demonstrating the undeniable capability of the single-pass L-band PolInSAR system for forest monitoring.

Highlights

Forests play a crucial role in Earth’s carbon cycle by absorbing carbon from the atmosphere and storing it in its biomass
This paper aims to evaluate the performance of forest height estimation using this dual-baseline TomoSAR configuration
The acquisition system used in this study offers the possibility to acquire MultiBaseline Polarimetric Interferometric SAR (MB-PolInSAR) data during a single pass of the airborne platform

Summary

Introduction

Forests play a crucial role in Earth’s carbon cycle by absorbing carbon from the atmosphere and storing it in its biomass. Forest characterization and monitoring are very important for tracking climate change and quantifying the global carbon cycle in the form of above-ground-biomass mapping. SAR remote sensing techniques that guarantee under-foliage penetration are able to provide reliable estimation of forest parameters on a global scale [1], with a suitable temporal and spatial resolution. Among the SAR-extracted forest parameters, forest height is a key descriptor, commonly used for the estimation of forest volume and above-ground biomass. Polarimetric SAR Interferometry (PolInSAR), together with an appropriate inversion model such as the Random Volume Over Ground (RVOG) [2,3,4], has demonstrated a significant success for the recovery of canopy height and of the underlying ground elevation. Forest height estimation has been successfully achieved via some well-known repeat-pass L-band

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Discussion

Conclusion