An oceanic heat transport pathway to the Amundsen Sea Embayment

Abstract

AbstractThe Amundsen Sea Embayment (ASE) on the West Antarctic coastline has been identified as a region of accelerated glacial melting. A Southern Ocean State Estimate (SOSE) is analyzed over the 2005–2010 time period in the Amundsen Sea region. The SOSE oceanic heat budget reveals that the contribution of parameterized small‐scale mixing to the heat content of the ASE waters is small compared to advection and local air‐sea heat flux, both of which contribute significantly to the heat content of the ASE waters. Above the permanent pycnocline, the local air‐sea flux dominates the heat budget and is controlled by seasonal changes in sea ice coverage. Overall, between 2005 and 2010, the model shows a net heating in the surface above the pycnocline within the ASE. Sea water below the permanent pycnocline is isolated from the influence of air‐sea heat fluxes, and thus, the divergence of heat advection is the major contributor to increased oceanic heat content of these waters. Oceanic transport of mass and heat into the ASE is dominated by the cross‐shelf input and is primarily geostrophic below the permanent pycnocline. Diagnosis of the time‐mean SOSE vorticity budget along the continental shelf slope indicates that the cross‐shelf transport is sustained by vorticity input from the localized wind‐stress curl over the shelf break.