Oceanic conditions in the Barrow Coastal Polynya revealed by a 10-year mooring time series

•A wind-driven hybrid polynya recurs annually throughout the 10-year time period.•Pacific and Atlantic influences impact water mass formation in the region.•Upwelled Atlantic-origin warm water also delays freeze onset in some cases.•Significance of summer/autumn oceanic preconditions on winter processes.•Step increase in warming after 2016, likely originating from upstream Bering inflow.