Characterizing the Interannual Variability of North Atlantic Subpolar Overturning
Abstract Variability of the Atlantic Meridional Overturning Circulation (MOC) has drawn extensive attention due to its impact on the global redistribution of heat and freshwater. Here we present the latest time series (2014–2022) of the Overturning in the Subpolar North Atlantic Program and characterize MOC interannual variability. We find that any single boundary current captures ∼30% of subpolar MOC interannual variability. However, to fully resolve MOC variability, a wide swath across the eastern subpolar basin is needed; in the Labrador Sea both boundaries are needed. Through a volume budget analysis for the subpolar basins' lower limbs, we estimate the magnitude of unresolved processes (e.g., diapycnal mixing) required to close the mean budget (∼2 Sv). We find that in the eastern subpolar basin surface‐forced transformation variability is linked to lower limb volume variability, which translates to MOC changes within the same year. In contrast, this linkage is weak in the Labrador Sea.
Authors
- Fiammetta Straneo (ORCID: https://orcid.org/0000-0002-1735-2366)
- Frédéric Cyr (ORCID: https://orcid.org/0000-0002-1581-7502)
- N. Penny Holliday (ORCID: https://orcid.org/0000-0002-9733-8002)
- Igor Yashayaev (ORCID: https://orcid.org/0000-0002-6976-7803)
- Yao Fu (ORCID: https://orcid.org/0000-0003-2227-3694)
- M. Susan Lozier (ORCID: https://orcid.org/0000-0003-4129-6349)
- Neil Fraser (ORCID: https://orcid.org/0000-0002-2171-9060)
- Johannes Karstensen (ORCID: https://orcid.org/0000-0001-5044-7079)
- Stuart A. Cunningham (ORCID: https://orcid.org/0000-0001-9439-5442)
- Tiago Carrilho Biló (ORCID: https://orcid.org/0000-0002-4007-5862)
- Robert S. Pickart (ORCID: https://orcid.org/0000-0002-7826-911X)
- Ahmad Fehmi Dilmahamod (ORCID: https://orcid.org/0000-0003-1110-940X)
- Kristin Burmeister (ORCID: https://orcid.org/0000-0003-3881-0298)
- William E. Johns (ORCID: https://orcid.org/0000-0002-1093-7871)
- Amy S. Bower (ORCID: https://orcid.org/0000-0003-0902-4984)
- Brad deYoung (ORCID: https://orcid.org/0000-0002-4145-2623)
- M. Femke de Jong (ORCID: https://orcid.org/0000-0001-5683-0570)
- Nora Fried (ORCID: https://orcid.org/0000-0001-5457-1026)
- Feili Li (ORCID: https://orcid.org/0000-0002-3073-9813)
Institutions
- Memorial University of Newfoundland (CA)
- Georgia Institute of Technology (US)
- Fisheries and Oceans Canada (CA)
- University of Miami (US)
- Xiamen University (CN)
- National Oceanography Centre (GB)
- Bedford Institute of Oceanography (CA)
- Harvard University Press (US)
- GEOMAR Helmholtz Centre for Ocean Research Kiel (DE)
- Institute of Landscape Ecology of the Slovak Academy of Sciences (SK)
- Royal Netherlands Institute for Sea Research (NL)
- NOAA National Marine Fisheries Service Northwest Fisheries Science Center (US)
- Woods Hole Oceanographic Institution (US)
- University of South Florida St. Petersburg (US)
- University of Maine (US)
- Scottish Association For Marine Science (GB)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2025-09-27
- DOI
- https://doi.org/10.1029/2025gl114672
- Citations
- 3
- Primary Topic
- Meteorological Phenomena and Simulations
- Type
- article
- Field-Weighted Citation Impact
- 3.90