Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic

N. Penny Holliday, Manfred Bersch, Barbara Berx, Léon Chafik, Stuart Cunningham, Cristian Florindo-López, Hjálmar Hátún, William Johns, Simon A. Josey, Karin Margretha H. Larsen, Sandrine Mulet, Marilena Oltmanns, Gilles Reverdin, Tom Rossby, Virginie Thierry, Hedinn Valdimarsson, Igor Yashayaev

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Abstract

The Atlantic Ocean overturning circulation is important to the climate system because it carries heat and carbon northward, and from the surface to the deep ocean. The high salinity of the subpolar North Atlantic is a prerequisite for overturning circulation, and strong freshening could herald a slowdown. We show that the eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of measurements. The cause was unusual winter wind patterns driving major changes in ocean circulation, including slowing of the North Atlantic Current and diversion of Arctic freshwater from the western boundary into the eastern basins. We find that wind-driven routing of Arctic-origin freshwater intimately links conditions on the North West Atlantic shelf and slope region with the eastern subpolar basins. This reveals the importance of atmospheric forcing of intra-basin circulation in determining the salinity of the subpolar North Atlantic.

Original languageEnglish (US)
Article number585
JournalNature communications
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2020

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Holliday, N. P., Bersch, M., Berx, B., Chafik, L., Cunningham, S., Florindo-López, C., Hátún, H., Johns, W., Josey, S. A., Larsen, K. M. H., Mulet, S., Oltmanns, M., Reverdin, G., Rossby, T., Thierry, V., Valdimarsson, H., & Yashayaev, I. (2020). Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic. Nature communications, 11(1), [585]. https://doi.org/10.1038/s41467-020-14474-y