Does the Beaufort Gyre Freshwater Storage Directly Respond to Changes in Bering Strait Inflow? Insights From NEMO Modeling Experiments

The storage/release of freshwater in the Beaufort region has changed rapidly since the early 2000s. Using a suite of coupled ocean‐sea ice Nucleus for European Modeling of the Ocean (NEMO) model simulations with different configurations, resolutions, versions of sea ice module, and atmospheric and runoff forcings, we review hydrographic changes in the Beaufort region and examine model performance from 2004 to 2019. We find that the global configuration better reproduces the observed Beaufort freshwater content than the regional configuration, regardless of resolution or forcing. The global configuration also improves the vertical thermohaline structure with reduced upper ocean model biases, although deficiencies in the mixing scheme remain. The global simulation that best represents freshwater conditions shows that seasonal freshwater changes are mainly modulated by sea ice changes, whereas interannual variability is primarily driven by lateral freshwater fluxes. Comparisons with mooring observations near the Bering Strait reveal that global simulations underestimate volume transport and simulate fresher, warmer inflow than observed. In contrast, regional simulations better capture the Bering Strait inflow and more closely match the observed temperature and salinity. Thus, a more accurate representation of Bering Strait inflow does not necessarily mean a better representation of freshwater in the Beaufort Gyre. These results highlight the dominant role of regional Arctic processes, rather than gateway exchanges, in regulating Beaufort Gyre freshwater storage. Therefore, a future enhancement of the Bering Strait inflow fluxes (volume and freshwater) does not necessarily mean a fresher Beaufort Gyre.