A direct estimate of poleward volume, heat, and freshwater fluxes at 59.5°N between Greenland and Scotland

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Rossby, T., Reverdin, Gilles, Chafik, Léon, Søiland, Henrik
• Other Authors: Graduate School of Oceanography Narragansett, University of Rhode Island (URI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: currents; MOC; heat flux; freshwater flux; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Greenland; Irminger Sea; Rockall Trough; North Atlantic
• Online Access: https://hal.science/hal-01630799; https://hal.science/hal-01630799/document; https://hal.science/hal-01630799/file/JGR%20Oceans%20-%202017%20-%20Rossby%20-%20A%20direct%20estimate%20of%20poleward%20volume%20heat%20and%20freshwater%20fluxes%20at%2059%205%20N%20between%20Greenland.pdf; https://doi.org/10.1002/2017JC012835

International audience The meridional overturning circulation (MOC) in the North Atlantic plays a major role in the transport of heat from low to high latitudes. In this study, we combine recent measurements of currents from the surface to >700 m from a shipboard acoustic Doppler current profiler with Argo profiles (to 2000 m) to estimate poleward volume, heat, and freshwater flux at 59.5°N between Greenland and Scotland. This is made possible thanks to the vessel Nuka Arctica that operates on a 3 week schedule between Greenland and Denmark. For the period late 2012 to early 2016, the deseasoned mean meridional overturning circulation reaches a 18.4 ± 3.4 Sv maximum at the σθ = 27.55 kg m -3 isopycnal, which varies in depth from near the surface in the western Irminger Sea to 1000 m in Rockall Trough. The total heat and freshwater fluxes across 59.5°N = 399 ± 74 TW and −0.20 ± 0.04 Sv, where the uncertainties are principally due to that of the MOC. Analysis of altimetric sea surface height variations along exactly the same route reveals a somewhat stronger geostrophic flow north during this period compared to the 23 year mean suggesting that for a long-term mean the above flux estimates should be reduced slightly to 17.4 Sv, 377 TW, and −0.19 Sv, respectively, with the same estimate uncertainties. The ADCP program is ongoing.