CONTRASTS (PS149) Contrasts of sea ice regimes in the Arctic Ocean during melt season The Polarstern expedition CONTRASTS (2 July to 1 September 2025, also named PS149, ArcWatch-3) investigates the causes [...] The aircraft campaign IceBird summer 2025 complements with regional surveys. Sea ice station with Polarstern (example from MOSAiC 2020). The vessel is moored to the ice floe. Measurements are performed and [...] autonomous devices. (Graphic: Alfred-Wegener-Institut) On-route measurements and regional surveys With Polarstern, the helicopters and also the aircrafts on the IceBird summer expedition (from Station Nord), we