Lessons learned from UAV surveys over drifting sea ice at high latitudes

Abstract. In this study, we provide an overview of the challenges encountered when operating consumer grade Unmanned Aerial Vehicles (UAVs) or drones over high-latitude Arctic pack ice. A major obstacle in generating void-free orthomosaics and Digital Elevation Models (DEMs) of ice floes is their drift speed, which can easily exceed 0.5 m s^-1 in the central Arctic Ocean. Furthermore, there is no commercial solution for operating UAV grid flight missions north of 85° N latitude. To address these issues, we tested and present a novel approach for flying autonomous grid missions at high latitudes including a pre- and post-flight drift correction scheme. Using the resulting data, we generated drift-corrected orthomosaics and DEMs for all ice floes visited during the ArcWatch-2 cruise in August/September 2024. In addition to the UAV camera system we tested a drone based laser scanner and incorporated measurements from drifting Global Navigation Satellite System (GNSS) stations for referencing and validation. Finally, we demonstrate the potential of drone acquired data for deriving ice thickness estimates, surface type classifications and melt pond depth retrievals. Our results offer the potential to upscale in situ measurements and can contribute to better mass balance estimates and meltwater quantification.