batch_auto_20260713 202607131256465730 BOEM ESP geoESPIS ESPIS@boem.gov Bureau of Ocean Energy Management Landfast Ice in the Beaufort and Chukchi Seas and Under Ice Circulation Processes on the Beaufort Sea Shelf University of Alaska Fairbanks University of Alaska Fairbanks In this study, we have created a 27-year climatology of landfast ice extent in the Arctic Outer Continental Shelf (OCS), which we refer to as the EM2024 dataset. This record shows there are significant trends toward a shorter duration and reduced extent of landfast ice across the region. In-situ field observations of landfast ice that suggests landfast ice may be less susceptible to basal melting in spring as long as it remains landfast. We also investigated the specific role that storms may play in destabilizing landfast ice and found that a significant number of breakout events are associated with the occurrence of storms in the southern Bering Sea, which is consistent with previous suggestions that storm-triggered shelf waves may destabilize landfast ice. Lastly, we simulated 25 years of past landfast ice extent within the Arctic OCS by implementing a basal shear stress parameterization in a modular ocean model 6-sea ice simulator 2 (MOM6-SIS2) coupled ice-ocean model. In doing so, we demonstrate that the Alaska Arctic OCS is an ideal test ground for refining model parameter choices and the EM2024 dataset represents a valuable benchmark for quantifying model performance. 1699293 U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program https://doi.org/10.13039/100012475 M19AC00021 10.67297/9A1E33 https://boem.gov/awardpages/100275