Labrador Sea subsurface density as a precursor of multidecadal variability in the North Atlantic: a multi-model study
Year: 2021
Type: article
Abstract: . The Subpolar North Atlantic (SPNA) is a region with prominent decadal variability that has experienced remarkable warming and cooling trends in the last few decades. These observed trends have been preceded by slow-paced increases and decreases in the Labrador Sea density (LSD), which are thought to be a precursor of large scale ocean circulation changes. This article analyses the inter-relationships between the LSD and the wider North Atlantic across an ensemble of coupled climate model simulations. In particular, it analyses the link between subsurface density and the deep boundary density, the Atlantic Meridional Overturning Circulation (AMOC), the Subpolar Gyre (SPG) circulation, and the upper ocean temperature in the eastern SPNA. All simulations exhibit considerable multidecadal variability in the LSD and the ocean circulation indices, which are found to be interrelated. LSD is strongly linked with the strength of subpolar AMOC and gyre circulation, and is also linked with the subtropical AMOC, although the strength of this relationship is model dependent. The connectivity of LSD with the subtropics is found to be sensitive to different model features, including: the mean density stratification in the Labrador Sea; the strength and depth of the AMOC; and the depth at which the LSD propagates southward along the western boundary. Several of these quantities can also be computed from observations, and comparison with these observation-based quantities suggests that models representing a weaker link with the subtropical AMOC may be more realistic. This would imply that RAPID AMOC measurements might not be adequate to represent decadal to multidecadal changes in the subpolar overturning circulation.
Source: Earth System Dynamics
Institutions: Barcelona Supercomputing Center, National Centre for Atmospheric Science, University of Reading, Sorbonne Université, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques, National Oceanography Centre, Met Office, NSF National Center for Atmospheric Research
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,585
Awards: G1623654645, NSFGEO-NERC: Wider Impacts of Subpolar nortH atlantic decadal variaBility on the OceaN and atmospherE (WISHBONE), G2382347013, The North Atlantic Climate System Integrated Study, The North Atlantic Climate System Integrated Study, DYNamics and predictability of the Atlantic Meridional Overturning and Climate (DYNAMOC), G3279936179, G3394399528, G4227455053, Wider Impacts of Subpolar nortH atlantic decadal variaBility on the OceaN and atmospherE' (WISHBONE), Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS), The North Atlantic Climate System Integrated Study (ACSIS) - 1 year extension, DYNamics and predictability of the Atlantic Meridional Overturning and Climate (DYNAMOC), G8585165044, The North Atlantic Climate System Integrated Study (ACSIS) - 1 year extension, Wider impacts of Subpolar North Atlantic decadal variability on the ocean and atmosphere (WISHBONE)
OpenAlex ID: W3095801002