Wide area forest height mapping using Tandem-X standard mode data

In this paper we report results of a study aimed at assessing the potential for using the standard mode of TanDEM-X (single polarization HH, single baseline and single-pass radar interferometry) to estimate forest canopy heights over two Canadian forest test sites, where supporting LIDAR data is available for validation. We first apply two coherence correction factors to TanDEM-X data, one for signal-to-noise ratio (SNR) based on noise statistics from TanDEM-X metadata and the other on a system correction based on bare surface reference scattering. We then use coherence amplitude of the interferogram and interferometric wavenumber k_z to estimate forest canopy heights. The radar heights are validated against a LIDAR CHM (Canopy Height Model) reference. A simple linear scaling of the TanDEM-X height products based on a relatively small LIDAR calibration patch is used to extend the canopy height products over a mosaic of multiple swaths for very wide area forest height mapping using radar coherence.