Storm-driven upwelling contributes to Beaufort Gyre intensification through rapid geostrophic adjustment and eddy-related freshwater redistribution

Abstract The Alaskan North Slope (ANS) is a region of recurrent wind-driven upwelling, but the extent to which these events influence Beaufort Gyre (BG) variability and Arctic freshwater redistribution remains uncertain. We combine ERA5 winds, mooring velocity and hydrography, satellite dynamic ocean topography, SODA reanalysis, and idealized MITgcm experiments. During 2008–2020, 380 mooring-observed upwelling events were identified; 377 (99.2%) occurred under upwelling-favorable winds, and event-integrated wind forcing was correlated with observed upwelling intensity ( r = 0.75). Monthly ANS upwelling activity was associated with enhanced DOT-derived BG strength during the Monthly ANS upwelling activity was significantly associated with enhanced DOT-derived BG strength during the event month after accounting for sea ice and the previous-month BG state; the lag-1 coefficient remained positive but was not statistically significant after accounting for sea ice. Upwelling also produced an immediate decrease in freshwater content on the shelf-ward side of the 1000-m isobath, while larger ANS freshwater losses preceded increased freshwater content in the adjacent southern-BG band after approximately 3–6 months. The observations and process model support a rapid geostrophic-adjustment pathway and a slower, spatially heterogeneous freshwater-redistribution pathway. In the passive-tracer experiment, 38.10% of the initially tagged shelf–slope halocline water crossed the 60-km slope-foot section within six days, and the velocity–tracer covariance accounted for 68.17% of the resolved cumulative transport. The result is interpreted as evidence for an eddy-related early-stage offshore pathway.