The Northeast Water Polynya, Greenland: Climatology, Atmospheric Forcing and Ocean Response

The Northeast Water Polynya is a significant annually recurring summertime Arctic polynya, located off the coast of Northeast Greenland. It is important for marine wildlife and affects local atmospheric and oceanic processes. In this study, over 40 years of observational and reanalysis products (ERA5 and ORAS5) are analyzed to characterize the polynya's climatology and ascertain forcing mechanisms. The Northeast Water Polynya has high spatiotemporal variability; its location, size and structure vary interannually, and the period for which it is open is changing. We show this variability is largely driven by atmospheric forcing. The polynya extent is determined by the direction of the near-surface flow regime, and the relative locations of high and low sea-level pressure centers over the region. The surface conditions also impact the oceanic water column, which has a strong seasonal cycle in potential temperature and salinity, the amplitude of which decreases with depth. The ocean reanalyses also show a significant warming trend at all depths and a freshening near the surface consistent with greater ice melt, but salinification at lower depths (similar to 200 m). As the Arctic region changes due to anthropogenic forcing, the sea-ice edge is migrating northwards and the Northeast Water Polynya is generally opening earlier and closing later in the year. This could have significant implications for both the atmosphere and ocean in this complex and rapidly changing environment. Polynya's are areas of open water surrounded by sea ice. These features are important for marine wildlife and can impact how the atmosphere and ocean interact. The Northeast Water Polynya is one example from the Arctic. Each summer, it appears off the coast of Northeast Greenland. In this research we use data from the last 40 years to study this polynya. We find that its location, size and structure varies from year to year. The period for which it is open each year also changes. We conclude that these differences are due to changes in the wind direction near the surface. Winds that flow from south to north over the region are linked to a larger polynya. Winds that flow from north to south are linked to a smaller polynya. With climate change, the Northeast Water Polynya is opening earlier and closing later in the year. In the future, this polynya may no longer form as it does now, which will impact the local environment and wildlife. A climatological study of the Northeast Water Polynya reveals spatial, interannual and decadal variability The summertime polynya extent closely correlates to near-surface winds, largely dictated by the orientation of the pressure gradient across Fram Strait Between 1980 and 2022, the duration of the Northeast Water Polynya, and associated oceanic warming, increased