An Assessment of SAOCOM L-Band PolInSAR Capabilities for Canopy Height Estimation: A Case Study Over Managed Forests in Argentina

This work presents the first results of canopy height mapping with L-Band SAOCOM data by means of Polarimetric SAR Interferometry (PolInSAR). SAOCOM stands forSatélite Argentino de Observación con Microondasand it is operated by CONAE, the argentinean space agency. For this study case, a colocated temporal series of SAOCOM fully polarimetric images covering the year 2021 was acquired, with a temporal baseline of 8 to 16 days between each acquisition. The study area corresponds to managed forests in Corrientes, Argentina. which is one of the main forest production regions in the country. Field measurements provided by forest owners were available in order to validate the obtained results, along with canopy height measurements from the Global Ecosystem Dynamics Investigation (GEDI) mission. In this work a multi-baseline PolInSAR approach was adopted, following the methodology proposed by previous works. Field data measurements collected over the study periods were used to select the RVoG-inverted maps that best represented the different forest heights present in the study areas. The results show that this multi-baseline selection approach is more appropriate than a single-baseline one, given the high variability that SAOCOM presents in the spatial baseline between acquisitions, and the lack of orbital control over this parameter. Two forest fields were selected to validate this methodology: one for training and calibrating the model, and another for independent validation. The height maps from the latter yielded an averageR²of 0.72 and a mean$RMSE$of 2.35 m., in agreement with the figures obtained in similar studies. This study presents, for the first time, canopy height maps of 8 and 16-day temporal baselines, L-band, orbital interferograms. The conclusions yielded by this research represent a qualitative and quantitative evaluation of SAOCOM PolInSAR capabilities for forest height mapping. It is also relevant to assess the suitability of the RVoG model to characterize the structure of these forests with L-band data retrieved by the Argentinean constellation.