FN Archimer Export Format PT J TI Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 BT AF MERCIER, Herle LHERMINIER, Pascale SARAFANOV, Artem GAILLARD, Fabienne DANIAULT, Nathalie DESBRUYERES, Damien FALINA, Anastasia FERRON, Bruno GOURCUFF, Claire HUCK, Thierry THIERRY, Virginie AS 1:1;2:2;3:3;4:2;5:4;6:1;7:3;8:1;9:1;10:1;11:2; FF 1:;2:PDG-ODE-LPO;3:;4:PDG-ODE-LPO;5:;6:;7:;8:;9:;10:;11:PDG-ODE-LPO; C1 CNRS, UBO, Ifremer IRD, Ifremer Ctr Brest,Lab Phys Oceans,UMR 6523, F-29280 Plouzane, France. IFREMER, IRD, UBO, Ifremer Ctr Brest,Lab Phys Oceans,UMR 6523, F-29280 Plouzane, France. PP Shirshov Oceanol Inst, Moscow, Russia. UBO, CNRS, Ifremer IRD, Lab Phys Oceans,UMR 6523, F-29285 Brest, France. C2 CNRS, FRANCE IFREMER, FRANCE PP SHIRSHOV OCEANOL INST, RUSSIA UBO, FRANCE SI BREST SE PDG-ODE-LPO UM LOPS IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france copubli-int-hors-europe IF 3.512 TC 100 UR https://archimer.ifremer.fr/doc/00165/27583/25742.pdf LA English DT Article CR OVIDE 1 OVIDE 2 OVIDE 3 OVIDE 4 OVIDE 5 BO Thalassa Maria S. Merian AB The meridional overturning circulation (MOC) in the North Atlantic transports heat from the subtropics to high latitudes and hence plays an important role in the Earth’s climate. A region crucial for the MOC is the northern North Atlantic and the adjacent Nordic Seas, where waters transported northward in the MOC upper limb progressively cool, gain density and eventually sink. Here we discuss the variability of the gyre circulation, the MOC and heat flux as quantified from a joint analysis of hydrographic and velocity data from six repeats of the Greenland to Portugal OVIDE section (1997–2010), satellite altimetry and Argo float measurements. For each repeat of the OVIDE section, the full-depth absolute circulation and transports were assessed using an inverse model constrained by ship-mounted Acoustic Doppler Current Profiler data and by an overall mass balance. The obtained circulation patterns revealed remarkable transport changes in the whole water column and evidenced large variations (up to 50% of the lowest value) in the magnitude of the MOC computed in density coordinates (MOCσ). The extent and time scales of the MOCσ variability in 1993–2010 were then evaluated using a monthly MOCσ index built upon altimetry and Argo. The MOCσ index, validated by the good agreement with the estimates from repeat hydrographic surveys, shows a large variability of the MOCσ at OVIDE on monthly to decadal time scales. The intra-annual variability is dominated by the seasonal component with peak-to-peak amplitude of 4.3 Sv (1 Sv = 106 m3 s–1). On longer time scales, the MOCσ index varies from less than 15 Sv to about 25 Sv. It averages to 18.1 ± 1.4 Sv and shows an overall decline of 2.5 ± 1.4 Sv (95% confidence interval) between 1993 and 2010. The heat flux estimates from repeat hydrographic surveys, which vary between 0.29 and 0.70 ± 0.05 PW, indicate that the heat flux across the OVIDE section is linearly related to the MOCσ intensity (0.054Sv/PW). Regional terms: North Atlantic Ocean; Subpolar gyre; Irminger Sea; Iceland Basin; West European Basin; Iberian Abyssal Plain PY 2015 PD MAR SO Progress In Oceanography SN 0079-6611 PU Pergamon-elsevier Science Ltd VL 132 UT 000352038700010 BP 250 EP 261 DI 10.1016/j.pocean.2013.11.001 ID 27583 ER EF