Century-long cooling trend in subpolar North Atlantic forced by atmosphere: an alternative explanation

Journal Article (Journal Article)

A well-known exception to rising sea surface temperatures (SST) across the globe is the subpolar North Atlantic, where SST has been declining at a rate of 0.39 (± 0.23) K century−1 during the 1900–2017 period. This cold blob has been hypothesized to result from a slowdown of the Atlantic Meridional Overturning Circulation (AMOC). Here, observation-based evidence is used to suggest that local atmospheric forcing can also contribute to the century-long cooling trend. Specifically, a 100-year SST trend simulated by an idealized ocean model forced by historical atmospheric forcing over the cold blob region matches 92% (± 77%) of the observed cooling trend. The data-driven simulations suggest that 54% (± 77%) of the observed cooling trend is the direct result of increased heat loss from the ocean induced by the overlying atmosphere, while the remaining 38% is due to strengthened local convection. An analysis of surface wind eddy kinetic energy suggests that the atmosphere-induced cooling may be linked to a northward migration of the jet stream, which exposes the subpolar North Atlantic to intensified storminess.

Full Text

Duke Authors

Cited Authors

  • Li, L; Lozier, MS; Li, F

Published Date

  • May 1, 2022

Published In

Volume / Issue

  • 58 / 9-10

Start / End Page

  • 2249 - 2267

Electronic International Standard Serial Number (EISSN)

  • 1432-0894

International Standard Serial Number (ISSN)

  • 0930-7575

Digital Object Identifier (DOI)

  • 10.1007/s00382-021-06003-4

Citation Source

  • Scopus