A direct estimate of poleward volume, heat, and freshwater fluxes at 59.5°N between Greenland and Scotland
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...
Published in: | Journal of Geophysical Research: Oceans |
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Main Authors: | , , , |
Other Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2017
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-01630799 https://hal.archives-ouvertes.fr/hal-01630799/document https://hal.archives-ouvertes.fr/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 |
Summary: | 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. |
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