EGU22-12662
https://doi.org/10.5194/egusphere-egu22-12662
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Surface oxygen balance in the Subantarctic Mode Water Formation region.

Pablo Trucco-Pignata1, Peter Brown2, Dorothee Bakker3, Hugh Venables4, Alberto Naveira-Garabato1, Filipa Carvalho2, Katsia Pabortsava2, Maribel García-Ibáñez3, Sheri White5, Stephanie Henson2, and Adrian Martin1
Pablo Trucco-Pignata et al.
  • 1University of Southampton, National Oceanography Centre, Southampton, United Kingdom of Great Britain – England, Scotland, Wales (pntp1n18@soton.ac.uk)
  • 2National Oceanography Centre, Southampton, UK
  • 3Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
  • 4British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
  • 5Woods Hole Oceanographic Institution, Woods Hole, MA, United States

In the Subantarctic Zone (SAZ) of the southeast Pacific, the densest, coolest, and freshest Subantarctic Mode Water (SAMW) is formed. There, water masses reset their physicochemical characteristics interchanging properties with the atmosphere, and play a critical role in global climate through their impact on the overturning circulation and oceanic heat and carbon uptake. We estimate the magnitude, variability and uncertainty of the air-sea flux of oxygen from five years of hourly observations around the Observatories Initiative (OOI) Southern Ocean mooring.

The magnitude of oxygen fluxes depends greatly on the parameterization used, particularly for high wind events. Hence, there is a need for validation of the high wind speed regime at high latitudes. Surface waters remain undersaturated from autumn to mid-spring, when most of the annual oxygen uptake occurs. We calculate a total annual flux into the ocean of -12.6 ± 3.4 mol m-2 yr-1, with a thermal component of -10.3 ± 2.6 mol m-2 yr-1 and a non-thermal component of -1.0 ± 0.3 mol m-2 yr-1. These results provide the first estimate of oxygen fluxes for the region from high-frequency observations, surpassing previous estimates for the entire SAZ by one order of magnitude.

How to cite: Trucco-Pignata, P., Brown, P., Bakker, D., Venables, H., Naveira-Garabato, A., Carvalho, F., Pabortsava, K., García-Ibáñez, M., White, S., Henson, S., and Martin, A.: Surface oxygen balance in the Subantarctic Mode Water Formation region., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12662, https://doi.org/10.5194/egusphere-egu22-12662, 2022.