How understanding storms reduces Southern Ocean heat and CO2 uptake uncertainty
Short description
Human emissions of greenhouse gases have significantly increased atmospheric concentrations of heat and COâ‚‚. The global ocean absorbs a substantial amount of this excess heat (93%) and COâ‚‚ (22%), mitigating severe climate warming. However, the mechanisms, especially in the Southern Ocean, are not fully understood, and climate models show large uncertainties.
This project aims to reduce these uncertainties and enhance understanding of small-scale ocean dynamics and storms on air-sea interactions, refining air-sea flux formulas for better climate model accuracy.
Novel field techniques will be employed to directly measure these fluxes in the sea-ice impacted region as part of the Swedish Polar Research Secretariat Pulse of the Weddell Sea Expedition.
Project members
Marcel du Plessis, Department of Marine 91̽»¨s

Sebastiaan Swart, Department of Marine 91̽»¨s
Bastien Queste, Department of Marine 91̽»¨s
Partners
Brian Ward, AirSea Laboratory and Ryan Institute, National University of Ireland

Sarah Nicholson, Council for Scientific and Industrial Research, South Africa

Carol-Anne Clayson, Woods Hole Oceanographic Institution, USA
John Prytherch, Uppsala University
Background
The Southern Ocean plays a crucial role in absorbing excess atmospheric heat (93%) and CO2 (22%), which helps mitigate climate warming. However, the mechanisms behind these processes, particularly the complex interactions between air and sea, and the influence of storms, remain unclear.
This lack of understanding leads to uncertainties in climate models, as current air-sea flux formulas may not accurately represent the unique conditions of the Southern Ocean.
Project goals
The project’s goals are to investigate how storms modulate ocean heat and CO2 uptake, uncover how storms interact with sub-grid scale ocean dynamics to influence air-sea exchange in sea ice regions, and improve bulk air-sea heat and CO2 flux formulas for sea ice regions and unique current and wave characteristics.
Ultimately, the overarching aim is to refine air-sea flux formulas for more accurate climate projections. The project plans involve a multi-pronged collaborative approach, integrating existing data with new field observations.
Project in three parts
First part: Observations
Existing observations of air-sea heat and CO2 exchange from the only standing Southern Ocean Flux mooring will be used to determine the role of storms in the seasonal to interannual trends of air-sea heat and CO2 uptake. This will reveal key storm characteristics and their relationship with air-sea fluxes and climate drivers.
Second part: Major fieldwork using state-of-the-art robotic instruments
The project will undergo a major fieldwork component as part of the supported by the Swedish Polar Research Secretariat
The expedition will leverage support from key collaborators to deploy an array of autonomous instruments, including Wave Gliders, Sailbuoys, an expendable spar buoy, and ocean profiling gliders, along with ship-based measurements, to observe air-sea heat and CO2 fluxes and upper ocean dynamics in the sea-ice impacted region.
Combining all these state-of-the-art robotic instruments with novel ultra high-resolution satellite observations of ocean flow and sea ice distribution from the Surface Water Ocean Topography (SWOT) mission will be key to understanding the feedback between storms, small-scale scale ocean dynamics, and air-sea exchange.
Third part: Reduce uncertainty in climate models
Using the new data provided in this project, the algorithms that are used to understand and model the heat and CO2 exchange between the ocean and atmosphere will be tested and refined with the goal to reduce uncertainty in modelled ocean warming and carbon uptake.
Impact
The project aims to enhance observational understanding of air-sea exchange in the Southern Ocean, providing key constraints for climate models. It will demonstrate the utility of autonomous instruments and improve flux uncertainty in weather and climate models.
The project contributes to UN Sustainable Development Goals 9, 13, and 14, contributing to international efforts like SOCAT and the IPCC.
Ultimately, the project will inform political decisions on climate change.
