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Title: Response of a Strongly Eddying Global Ocean to North Atlantic Freshwater Perturbations

Journal Article · · Journal of Physical Oceanography
 [1];  [1];  [2];  [2];  [2];  [3]
  1. Univ. of Utrecht (Netherlands). Dept. of Physics and Astronomy, and Inst. for Marine and Atmospheric Research Utrecht
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of New South Wales, Sydney, NSW (Australia). Climate Change Research Centre, and ARC Centre of Excellence for Climate System Science

The strongly eddying version of the Parallel Ocean Program (POP) is used in two 45-yr simulations to investigate the response of the Atlantic meridional overturning circulation (AMOC) to strongly enhanced freshwater input due to Greenland melting, with an integrated flux of 0.5 Sverdrups (Sv; 1 Sv ≡ 106 m3 s-1). For comparison, a similar set of experiments is performed using a noneddying version of POP. The aim is to identify the signature of the salt advection feedback in the two configurations. For this reason, surface salinity is not restored in these experiments. The freshwater input leads to a quantitatively comparable reduction of the overturning strength in the two models. To examine the importance of transient effects in the relation between AMOC strength and density distribution, the results of the eddy-resolving model are related to water mass transformation theory. The freshwater forcing leads to a reduction of the rate of light to dense water conversion in the North Atlantic, but there is no change in dense to light transformation elsewhere, implying that high density layers are continuously deflating. The main focus of the paper is on the effect of the AMOC reduction on the basinwide advection of freshwater. The low-resolution model results show a change of the net freshwater advection that is consistent with the salt advection feedback. However, for the eddy-resolving model, the net freshwater advection into the Atlantic basin appears to be unaffected, despite the significant change in the large-scale velocity structure.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
OSTI ID:
1565242
Journal Information:
Journal of Physical Oceanography, Vol. 44, Issue 2; ISSN 0022-3670
Publisher:
American Meteorological SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 25 works
Citation information provided by
Web of Science

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Cited By (9)

Observable, low-order dynamical controls on thresholds of the Atlantic meridional overturning circulation journal September 2019
Effects of Drake Passage on a strongly eddying global ocean: DRAKE PASSAGE IN AN EDDYING GLOBAL OCEAN journal May 2016
Emerging impact of Greenland meltwater on deepwater formation in the North Atlantic Ocean journal June 2016
Impact of climate variability on the tidal oceanic magnetic signal-A model-based sensitivity study: OCEAN TIDE MAGNETIC SIGNAL VARIABILITY journal August 2016
Recent progress in understanding climate thresholds: Ice sheets, the Atlantic meridional overturning circulation, tropical forests and responses to ocean acidification journal February 2018
Impacts of Basin-Scale Climate Modes on Coastal Sea Level: a Review journal August 2019
A realistic freshwater forcing protocol for ocean-coupled climate models journal September 2014
Resolution dependency of sinking Lagrangian particles in ocean general circulation models journal September 2020
Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic meridional overturning circulation journal November 2014

Figures / Tables (12)


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