Enhanced Ventilation in Energetic Regions of the Antarctic Circumpolar Current

• Main Authors: Dove, Lilian A., Balwada, Dhruv, Thompson, Andrew F., Gray, Alison R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2022
• Subjects: General Earth and Planetary Sciences; Geophysics; Antarctic; Southern Ocean; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1029/2021gl097574

Flow-topography interactions along the path of the Antarctic Circumpolar Current generate standing meanders, create regions of enhanced eddy kinetic energy (EKE), and modify frontal structure. We consider the impact of standing meanders on ventilation based on oxygen measurements from Argo floats and the patterns of apparent oxygen utilization (AOU). Regions of high-EKE have relatively reduced AOU values at depths 200–700 m below the base of the mixed layer and larger AOU variance, suggesting enhanced ventilation due to both along-isopycnal stirring and enhanced exchange across the base of the mixed layer. Vertical exchange is inferred from finite-size Lyapunov exponents, a proxy for the magnitude of surface lateral density gradients, which suggest that submesoscale vertical velocities may contribute to ventilation. The shaping of ventilation by standing meanders has implications for the temporal and spatial variability of air‒sea exchange. © 2022. American Geophysical Union. Issue Online: 06 July 2022. Version of Record online: 06 July 2022. Accepted manuscript online: 25 June 2022. Manuscript accepted: 16 June 2022. Manuscript revised: 13 June 2022. Manuscript received: 22 December 2021. L. A. Dove and A. F. Thompson acknowledge funding from National Science Foundation (NSF) award OCE-1756956, the David and Lucille Packard Foundation, and the Resnick Sustainability Institute. L. A. Dove was additionally supported by an NSF Graduate Research Fellowship. D. Balwada and A. R. Gray were supported by NSF Award OCE-1756882. A. R. Gray acknowledges additional funding through National Oceanic and Atmospheric Administration Award NA20OAR4320271 and through NSF's Southern Ocean Carbon and Climate Observations and Modeling Project under Awards PLR-1425989 and OPP-1936222. The authors are grateful for the comments of three anonymous reviewers, which led to the improvement of this manuscript. Data Availability Statement. The float data were collected and made freely available by the International Argo Program and ...