Contemporary and Future Drivers of CO2 and Heat in the Southern Ocean

Abstract

The contemporary Southern Ocean mitigates the effects of anthropogenic climate change through its disproportional uptake of carbon and heat. However, it is not well understood how this role will evolve under different emission and mitigation scenarios. The Southern Ocean also remains the largest source of global ocean uncertainty in the global estimates of CO2 and heat fluxes. While much has been achieved globally and regionally in constraining the variability and some of the mechanisms that drive Southern Ocean CO2 and heat fluxes separately, we propose that a significant part of the challenge lies in the lack of research on CO2 and heat together to better understand the feedback and the mechanisms that drive those feedbacks. This project aims to examine the changing role of the Southern Ocean in global climate by looking at the two main drivers CO2 and heat, in an integrated way using an unprecedented 10-year high resolution glider dataset from the 2012-2022 SOSCEx experiments, including two new experiments planned for this proposal, in combination with an established eddy resolving model BIOPERIANT12. We aim to gain a better understanding of how the interaction of atmospheric synoptic cycles (storms) and fine-scale (0.1-100 km) ocean processes influence seasonal-decadal variability of CO2 and heat fluxes. This will include the extent to which they feedback on each other and ultimately contribute to a better understanding of the role of the Southern Ocean in the global carbon-climate system.

The expected three outcomes are 1. Improved observational constraints for the contemporary seasonal-interannual variability of CO2 and heat fluxes. 2. Understanding of how storms and their interaction with fine-scale dynamics influence the seasonal and interannual variability of CO2 and heat fluxes. 3. Identify the potential mechanisms that could explain the decadal anomaly in CO2 fluxes at the end of the 20th century.