Mean full-depth summer circulation and transports at the northern periphery of the Atlantic Ocean in the 2000s

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Sarafanov, A., Falina, A., Mercier, H., Sokov, A., Lherminier, P., Gourcuff, C., Gladyshev, S., Gaillard, F., Daniault, Nathalie
• Other Authors: P.P. Shirshov Institute of Oceanology (SIO), Russian Academy of Sciences Moscow (RAS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Greenland; Reykjanes; Irminger Sea; Cape Farewell; Greenland-Scotland Ridge; Iceland; Nordic Seas; north atlantic current; North Atlantic
• Online Access: https://hal.science/hal-00691375; https://doi.org/10.1029/2011JC007572

International audience A mean state of the full-depth summer circulation in the Atlantic Ocean in the region in between Cape Farewell (Greenland), Scotland and the Greenland-Scotland Ridge (GSR) is assessed by combining 2002-2008 yearly hydrographic measurements at 59.5°N, mean dynamic topography, satellite altimetry data and available estimates of the Atlantic-Nordic Seas exchange. The mean absolute transports by the upper-ocean, mid-depth and deep currents and the Meridional Overturning Circulation (MOCσ = 16.5 ± 2.2 Sv, at σ0 = 27.55) at 59.5°N are quantified in the density space. Inter-basin and diapycnal volume fluxes in between the 59.5°N section and the GSR are then estimated from a box model. The dominant components of the meridional exchange across 59.5°N are the North Atlantic Current (NAC, 15.5 ± 0.8 Sv, σ0 < 27.55) east of the Reykjanes Ridge, the northward Irminger Current (IC, 12.0 ± 3.0 Sv) and southward Western Boundary Current (WBC, 32.1 ± 5.9 Sv) in the Irminger Sea and the deep water export from the northern Iceland Basin (3.7 ± 0.8 Sv, σ0 > 27.80). About 60% (12.7 ± 1.4 Sv) of waters carried in the MOCσ upper limb (σ0 < 27.55) by the NAC/IC across 59.5°N (21.1 ± 1.0 Sv) recirculates westward south of the GSR and feeds the WBC. 80% (10.2 ± 1.7 Sv) of the recirculating NAC/IC-derived upper-ocean waters gains density of σ0 > 27.55 and contributes to the MOCσ lower limb. Accordingly, the contribution of light-to-dense water conversion south of the GSR (∼10 Sv) to the MOCσ lower limb at 59.5°N is one and a half times larger than the contribution of dense water production in the Nordic Seas (∼6 Sv).