Helicopter-borne RGB orthomosaics and photogrammetric Digital Elevation Models from the MOSAiC Expedition

The Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition took place between October 2019 and September 2020 giving the rare opportunity to monitor sea ice properties over a full annual cycle. Here we present 24 high resolution orthomosaics and photogrammetric Digital Elevation Models (DEMs) representing the ice surface around the German icebreaker Polarstern between March 2020 and September 2020. The dataset is based on >34.000 images acquired by a helicopter-borne optical camera system covering areas between 1.8 km^2 and 96.5 km^2 around the ship. Depending on the flight pattern and altitude of the helicopter ground resolutions of the orthomosaics range between 3 cm and 50 cm. By combining the photogrammetric products with contemporaneously acquired Airborne Laser Scanner (ALS) reflectance measurements selected orthomosaics could be corrected for cloud shadows which is important for employing sea ice classification algorithms. The presented dataset is a valuable data source for the interdisciplinary MOSAiC community building a temporal and spatially resolved baseline to accompany various remote sensing and field work related projects