The Coldest and Densest Overflow Branch Into the North Atlantic is Stable in Transport, But Warming

The overflow of cold water through the Faroe Bank Channel (FBC) is the densest water crossing the Greenland-Scotland Ridge and the densest source for the Atlantic Meridional Overturning Circulation (AMOC). Here, we show that the overflow volume transport remained stable from 1996 to 2022, but that t...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Larsen, Karin Margretha Húsgarð, Hansen, Bogi, Hátún, Egil Hjálmar, Johansen, Guðrið Eriksdóttir, Østerhus, Svein, Olsen, Steffen Malskær
Format: Article in Journal/Newspaper
Language:English
Published: 2024
Subjects:
Faroe Bank
Greenland
Greenland-Scotland Ridge
North Atlantic
Online Access:https://hdl.handle.net/11250/3151641
https://doi.org/10.1029/2024GL110097
Description
Summary:The overflow of cold water through the Faroe Bank Channel (FBC) is the densest water crossing the Greenland-Scotland Ridge and the densest source for the Atlantic Meridional Overturning Circulation (AMOC). Here, we show that the overflow volume transport remained stable from 1996 to 2022, but that the bottom water warmed at an average rate of 0.1°C per decade, mainly caused by warming of deep waters upstream. The salinity of the overflow water has increased as a lagged and reduced response to the salinity increase seen in the upper-layer source waters. Therefore, the potential density of the bottom water over the FBC sill shows no statistically significant trend. After entrainment of warmer ambient waters downstream of the FBC, the nonlinear density dependence upon temperature implies, however, that the overflow contributed water of reduced density to the local overturning and the deep limb of the AMOC. publishedVersion

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