Long-term evolution of ocean eddy activity in a warming world

• Published in: Nature Climate Change
• Main Authors: Beech, Nathan, Rackow, Thomas, Semmler, Tido, Danilov, Sergey, Wang, Qiang, Jung, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Zenodo 2022
• Subjects: Ocean Eddies; Measurements; Earth System Modeling; Antarc*; Antarctic
• Online Access: https://doi.org/10.1038/s41558-022-01478-3

Abstract Mesoscale ocean eddies, an important element of the climate system, impact ocean circulation, heat uptake, gas exchange, carbon sequestration and nutrient transport. Much of what is known about ongoing changes in ocean eddy activity is based on satellite altimetry; however, the length of the altimetry record is limited, making it difficult to distinguish anthropogenic change from natural variability. Using a climate model that exploits a variable-resolution unstructured mesh in the ocean component to enhance grid resolution in eddy-rich regions, we investigate the long-term response of ocean eddy activity to anthropogenic climate change. Eddy kinetic energy is projected to shift poleward in most eddy-rich regions, to intensify in the Kuroshio Current, Brazil and Malvinas currents and Antarctic Circumpolar Current and to decrease in the Gulf Stream. Modelled changes are linked to elements of the broader climate including Atlantic meridional overturning circulation decline, intensifying Agulhas leakage and shifting Southern Hemisphere westerlies. Data Availability Geostrophic velocity anomalies derived from satellite altimetry anomalies are publicly available at https://doi.org/10.48670/moi-00148 . Model output from AWI-CM-1-1-MR in the CMIP6 framework, including ocean velocity and surface wind is publicly available at https://doi.org/10.22033/ESGF/CMIP6.359 (ref. 35). Daily sea surface height data used in this study is archived at the World Data Center for Climate at the DKRZ. Code Availability The code used to calculate geostrophic velocities and eddy kinetic energy according to the methods described in this paper and to produce the main analysis figures is available on Github GitHub - n-beech/awicm-cmip6-eke at v1.1 or can alternatively also be accessed via n-beech/awicm-cmip6-eke: 09-09-22 | Zenodo --- Acknowledgements The work described in this paper has received funding from the Helmholtz Association through the project 'Advanced Earth System Model Capacity' (project leader: T.J., support code: ...