The effects of temporal decorrelation and topographic slope on forest height retrieval using airborne repeat-pass L-band polarimetric SAR interferometry

We have explored the effects of temporal baseline and terrain slope on forest height estimation using L-band repeat-pass polarimetric synthetic aperture radar interferometry. Data were collected using NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar instrument over a study area exhibiting high slope topography in the Laurentides Wildlife Reserve of Québec, Canada. We used lidar-derived canopy height and terrain slope maps to quantify the decorrelation effects that distort the observed coherences compared to the random volume over ground forest model. We derived forest height maps for a number of different temporal baselines using both fixed model parameters and model parameters that varied with slope, and compared the results. Use of a look-up table for the terrain slope effects improved the estimated forest heights, but further work is necessary to see if slope corrections derived from lidar data for this study area can be applied to other study areas, or generalized to a theoretical model.