Sea ice conditions during POLARSTERN cruise PS138 (ArcWatch-1)

This dataset contains observations of sea-ice, snow, and meteorological conditions collected during the ArcWatch-1 expedition PS138 to the Central Arctic in August and September 2023. Hourly observations were conducted by cruise participants whenever the ship was cruising, following the ASSIST protocol (https://cryo.met.no/en/icewatch). Observations include sea-ice concentration and thickness, snow thickness, melt pond coverage and depth, visibility, cloud type and height, as well as three photographs per observation. These observations are part of a larger initiative to document sea-ice conditions using vessels operating in the Arctic and Antarctic (https://www.cen.uni-hamburg.de/en/icdc/data/cryosphere/seaiceparameter-shipobs.html).