Internal and forced variability along a section between Greenland and Portugal in the CLIPPER Atlantic model

Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv o...

Full description

Bibliographic Details
Published in:Ocean Dynamics
Main Authors: Treguier, Anne-marie, Gourcuff, Claire, Lherminier, Pascale, Mercier, Herle, Barnier, Bernard, Madec, Gurvan, Molines, Jean-marc, Penduff, Thierry, Czeschel, Lars, Boning, Claus
Format: Article in Journal/Newspaper
Language:English
Published: Springer 2006
Subjects:
Ocean model
Thermohaline circulation
North Atlantic
Climate variability
Oceanography
Greenland
East Greenland
east greenland current
north atlantic current
Online Access:https://archimer.ifremer.fr/doc/2006/publication-2199.pdf
https://doi.org/10.1007/s10236-006-0069-y
https://archimer.ifremer.fr/doc/00000/2199/
Description
Summary:Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of the z-coordinate overturning reveals model-data discrepancies: the vertical structure in the models does not change as much as the observed one. The East Greenland current variability is mainly wind-forced in the ATL6 model, while fluctuations due to eddies and instabilities explain a large part of the North Atlantic Current variability. The time-residual transport of dense water and heat due to eddy correlations between currents and properties is small across this section, which is normal to the direction of the main current.

Similar Items