Sea ice distribution in the Fram Strait during the Dansgaard-Oeschger events

We reconstructed sea ice conditions during the Dansgaard-Oeschger events in the eastern Fram Strait, covering a stadial and a following interstadial. This reconstruction is based on multiproxy analysis of marine sediment cores MD99-2304 and MD99-2303. Previous studies highlighted the importance of sea ice in the Nordic Seas because of its role in abrupt climate oscillations. However, how much the sea ice varied across the Nordic Seas has not been fully investigated. Our results, provided in an unprecedented detail, reveal that an extended sea ice cover occurred in the eastern Fram Strait with polynya activities during Greenland Stadial 9. The polynyas are also seen in model runs from the Norwegian Earth System Model (NorESM). A nearly perennial sea ice cover was observed in the research area around the Stadial-Interstadial transition, and seasonal openings gradually emerged at the catchment area of MD99-2304. During Greenland Interstadial 8, sea ice retreated north, forming a summer/fall ice edge in the eastern Fram Strait. The seasonal sea ice edge developed into a seasonal opening that extended even farther north than the research area in the later part during Greenland Interstadial 8. These discoveries can further contribute to a more complete understanding of the ocean-ice-atmosphere interactions during the abrupt climate change events.