EGU22-115
https://doi.org/10.5194/egusphere-egu22-115
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Glider observed surface buoyancy forcing from an atmospheric river in the Weddell Sea during austral summer 2019

Johan Edholm1, Sebastiaan Swart1,2, Marcel du Plessis1,3, and Sarah-Anne Nicholson3
Johan Edholm et al.
  • 1Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
  • 2Department of Oceanography, University of Cape Town, Rondebosch, South Africa
  • 3Southern Ocean Carbon‐Climate Observatory (SOCCO), CSIR, Cape Town, South Africa

Atmospheric rivers (ARs) dominate moisture transport globally, accounting for 90% of poleward atmospheric freshwater transport in the mid-to-high latitudes while only covering 10% of the surface. Yet, it is unknown what impact ARs have on the surface ocean buoyancy in the high latitudes. This is explored using high-resolution surface observations from a Wave glider deployed at a site in the Southern Ocean (54°S, 0°E) during austral summer. During this time (19 December 2018 - 12 February 2019, 55 days) we show that when ARs combine with storms over this area, the associated precipitation is enhanced significantly (162%). AR-induced precipitation events provided a major source of surface ocean buoyancy equivalent to the input of surface heat fluxes on a daily timescale. Cumulatively, ARs account for 44% of the summer precipitation equating to 9% of surface buoyancy gain. These results show that AR variability is a previously unaccounted driver of Southern Ocean surface buoyancy that may ultimately impact upper ocean water mass transformation and the dynamics of the ocean surface boundary layer.

How to cite: Edholm, J., Swart, S., du Plessis, M., and Nicholson, S.-A.: Glider observed surface buoyancy forcing from an atmospheric river in the Weddell Sea during austral summer 2019, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-115, https://doi.org/10.5194/egusphere-egu22-115, 2022.