Sea ice effects on stratification in Barrow Strait: a potential energy anomaly framework

Abstract Using a one-dimensional potential energy anomaly (PEA) framework we examine the development and erosion of density stratification in Barrow Strait within the Canadian Arctic Archipelago. PEA is the amount of work per unit volume required to completely mix the water column given a particular density profile. Many processes modify PEA, including surface buoyancy fluxes such as heating and cooling, ice melt and growth, precipitation and evaporation, and vertical mixing processes driven by the tides, winds, and ice drift. Using full-depth mooring data from Barrow Strait, augmented by reanalysis products, we quantify the one-dimensional surface fluxes and vertical mixing processes that affect PEA in this seasonally ice-covered region. Significant seasonality in PEA was observed, with high interannual variability. The PEA analysis shows that sea ice melt and growth played a major role in setting stratification year-round. Mixing by drifting sea ice and wind became seasonally important during summer periods, as did surface heating and cooling and precipitation and evaporation, though to a lesser extent. Other common shallow shelf sea processes like tidal mixing generally contributed the least. Our analysis also indicates that mechanisms, such as advection, influence water mass properties at this site. Despite the acknowledged caveats and assumptions made in our approach, the findings suggest that Barrow Strait stratification is shaped not only by local processes mediated by sea ice, but also by upstream changes, underscoring the region’s sensitivity to broader Arctic dynamics.