Arctic Lake Classification from NASA ABoVE Digital Color Infrared Airborne Imagery

The 2017 NASA Arctic-Boreal Vulnerability Experiment (ABoVE) aims to enhance understanding of Arctic ecologic and hydrologic processes using emerging NASA airborne remote sensing technologies. One such technology is AirSWOT, which aims to map surface water elevations in lake, wetland and river environments. The AirSWOT instrument suite includes a Ka-band experimental interferometric synthetic aperture radar and a NASA color infrared (CIR) Digital Camera System (DCS). In July and August 2017 NASA AirSWOT flew from southern Canada to Arctic Alaska, mapping >3,000 km² area including hundreds of lakes underlain by spatially varying geologic and permafrost conditions. This research aims to statistically assess the spatial variability of lake size and elevation changes to determine their sensitivity to broad-scale environmental gradients. To this end, we first map lakes from 1 m spatial resolution, 16-bit, multiband, CIR, orthomosaics using a probabilistic adaptive thresholding technique applied to a normalized difference water index (NDWI). Next, we validated the derived lake water mask using coincident in situ shoreline maps collected with GPS. Results will identify spatial variability in lake size and distribution across ~20 deg. of latitude. Findings should enhance understanding of changing Arctic hydrologic systems and associated environmental and geologic controls on surface water variability.