Submesoscale Fronts in the Antarctic Marginal Ice Zone and Their Response to Wind Forcing

• Published in: Geophysical Research Letters
• Main Authors: Swart, Sebastiaan, du Plessis, Marcel D., Thompson, Andrew F., Biddle, Louise C., Giddy, Isabelle, Linders, Torsten, Mohrmann, Martin, Nicholson, Sarahâ€Anne
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2020
• Subjects: submesoscales; mixedâ€layer; seaâ€ice; Southern Ocean; airâ€sea fluxes; gliders; Antarctic; Austral; Peddie; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1029/2019gl086649

Submesoscale flows in the ocean are energetic motions, O(1–10 km), that influence stratification and the distributions of properties, such as heat and carbon. They are believed to play an important role in seaâ€iceâ€impacted oceans by modulating airâ€seaâ€ice fluxes and seaâ€ice extent. The intensity of these flows and their response to wind forcing are unobserved in the seaâ€ice regions of the Southern Ocean. We present the first submesoscaleâ€resolving observations in the Antarctic marginal ice zone (MIZ) collected by surface and underwater autonomous vehicles, for >3 months in austral summer. We observe salinityâ€dominated lateral density fronts occurring at subâ€kilometer scales. Surface winds are shown to modify the magnitude of the mixedâ€layer density fronts, revealing strongly coupled atmosphereâ€ocean processes. We posture that these windâ€front interactions occur as a continuous interplay between front slumping and vertical mixing, which leads to the dispersion of submesoscale fronts. Such processes are expected to be ubiquitous in the Southern Ocean MIZ. © 2020 The Authors. This is an open access article under the terms of the Creative Commons Attributionâ€NonCommercialâ€NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is nonâ€commercial and no modifications or adaptations are made. Received 13 DEC 2019; Accepted 2 MAR 2020; Accepted article online 4 MAR 2020. This work was supported by the following grants: Wallenberg Academy Fellowship (WAF 2015.0186), Swedish Research Council (VR 2019â€04400), STINTâ€NRF Mobility Grant and NRFâ€SANAP (SNA170522231782), and AFT was supported by the Terrestrial Hazard Observations and Reporting (THOR) and ONR (N00014â€19â€1â€2421). We thank Sea Technology Services (STS), SANAP, the captain and crew of the S.A. Agulhas II for their fieldâ€work/technical assistance. We thank David Peddie of Offshore Sensing AS for assistance with the Sailbuoy. S.S. is grateful to Geoff Shilling and Craig ...