Is Only the Wind Field Controlling the Maximum Sea Ice Area in the Bering Sea?

Abstract

Over the past four decades, temporal variability in March sea ice area (SIA) within the Bering Sea occasionally contradicts prevailing northeasterly wind, raising doubt about the primary regulatory role of wind speed in governing maximum SIA. We argue that at least two spatial modes, extracted through the Empirical Orthogonal Function analysis, are necessary to explain the variations in the maximum SIA in the Bering Sea. Wind field emerges as the primary regulator of EOF1, governing both the direct influence of wind divergence (WD) and the indirect influence of meridional heat transport on sea ice. EOF2 is directly governed by ocean heat transport (OHT). Considering only the direct impact on sea ice, the OHT is directly responsible for the maximum SIA changes in 1995–2007, while in 2008–2014, the wind field is the largest driver. Since 2015, historically low SIA is attributed to significantly enhanced wind convergence and reduced zonal heat transport in the Gulf of Anadyr. Wind field directly controls the maximum SIA for less than half of the observation time, with OHT driving the rest. Declining trends observed in both WD and OHT suggests a future distribution pattern for the maximum SIA in the Bering Sea, characterized by an increase in the east and a decrease in the west. Long‐term retreat of sea ice on the western side of the Bering Sea is anticipated to exert significant impacts on local ecosystems, commercial activities, and even indigenous communities.