Tracking changes in inundation extent of a boreal wetland in Alaska using L-band SAR

The NASA Arctic Boreal Vulnerability Experiment (ABoVE) [1] has been collecting extensive spaceborne, airborne, and field-based measurements in the boreal regions of western North America to develop a better understanding of the vulnerability and resilience of these ecosystems. Now half-way through this ambitious 10-year experiment, unique time series measurements of various kinds (airborne sensor, in situ field measurements) are now available. The NASA-ISRO Synthetic Aperture Radar (NISAR) mission [3] has a requirement to measure inundation extent in wetland areas from the L-band SAR data that it will be collecting worldwide at 12-day intervals, after it is launched in 2022. The NISAR project is evaluating Cal/Val sites for validating its science requirements, including the wetlands in the Tanana River floodplain in the Bonanza Creek Experimental Forest (BCEF), 20 km southwest of Fairbanks [2]. This area includes a long-term research project funded by NSF and USGS (the Alaska Peatland Experiment - APEX) where measurements have been collected since 2004 to study processes controlling carbon storage in this moderately rich fen. In this paper, we examine the L-band UAVSAR airborne SAR data that has been acquired over wetlands in this region since 2017, compare these data against in situ estimates of inundation extent for this area, and classify the UAVSAR data into inundation-related classes