Pan-Atlantic decadal climate oscillation linked to ocean circulation

• Published in: Communications Earth & Environment
• Main Authors: Nnamchi, Hyacinth C., Farneti, Ricardo, Keenlyside, Noel S., Kucharski, Fred, Latif, Mojib, Reintges, Annika, Martin, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2023
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: https://oceanrep.geomar.de/id/eprint/58197/; https://oceanrep.geomar.de/id/eprint/58197/1/s43247-023-00781-x.pdf; https://www.nature.com/articles/s43247-023-00781-x; https://doi.org/10.1038/s43247-023-00781-x

Atlantic climate displays an oscillatory mode at a period of 10–15 years described as pan-Atlantic decadal oscillation. Prevailing theories on the mode are based on thermodynamic air-sea interactions and the role of ocean circulation remains uncertain. Here we uncover ocean circulation variability associated with the pan-Atlantic decadal oscillation using observational datasets from 1900–2009. Specifically, a sea level-derived index of ocean circulation also exhibits 10-15 year periodicity and leads the surface climate oscillation. The underlying ocean circulation links the extratropical and tropical Atlantic, where the maximum variance in surface-ocean temperature feeds back on the North Atlantic Oscillation (the leading mode of atmospheric variability over the North Atlantic region). Our findings imply that, rather than a passive role postulated by the thermodynamic paradigm, ocean circulation across the Atlantic plays an active role for the pan-Atlantic decadal climate oscillation.