FN Archimer Export Format
PT J
TI Observation‐based estimates of Eulerian‐mean boundary downwelling in the western subpolar North Atlantic
BT 
AF Liu, Yingjie
   Desbruyères, Damien
   Mercier, Herle
   Spall, M. A.
AS 1:1;2:1;3:3;4:2;
FF 1:PDG-ODE-LOPS-OH;2:PDG-ODE-LOPS-OH;3:;4:;
C1 University of Brest CNRS Ifremer IRD Laboratoire d'Océanographie Physique et Spatiale ,UMR6523 IUEM Ifremer centre de Brest 29280 PLOUZANE, France
   Woods Hole Oceanographic Institution ,Woods Hole MA, USA
   University of Brest CNRS Ifremer IRD Laboratoire d'Océanographie Physique et Spatiale ,UMR6523 IUEM Ifremer centre de Brest 29280 PLOUZANE, France
C2 IFREMER, FRANCE
   WHOI, USA
   CNRS, FRANCE
SI BREST
SE PDG-ODE-LOPS-OH
UM LOPS
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
   copubli-int-hors-europe
IF 5.2
TC 2
UR https://archimer.ifremer.fr/doc/00765/87665/93161.pdf
   https://archimer.ifremer.fr/doc/00765/87665/93162.pdf
LA English
DT Article
CR OVIDE
   OVIDE 2018
BO Thalassa
DE ;AMOC;subpolar North Atlantic;downwelling;observations
AB A significant fraction of the Eulerian-mean downwelling feeding the lower limb of the Atlantic Meridional Overturning Circulation (AMOC) occurs along the subpolar North Atlantic continental slopes and is maintained by along-boundary densification and large-scale geostrophic balance. We here use Argo and shipboard hydrography data to map the 2002-2015 long-term mean density field along the boundary via a dedicated optimal interpolation tool. The overall downstream densification implies an Eulerian-mean downwelling of 2.12 ± 0.43 Sv at 1100 m depth between Denmark Strait and Flemish Cap. A clear regional pattern emerges with downwelling in the Irminger Sea and western Labrador Sea and upwelling along Greenland western continental slope. Comparisons with independent cross-basin estimates confirm that vertical overturning transport across the marginal seas of the subpolar North Atlantic mainly occurs along the continental slopes, and suggest the usefulness of hydrographic data in providing quantitative information about the sinking branch of the AMOC. Plain Language Summary The Atlantic Meridional Overturning Circulation (AMOC), a critical component of the Earth's climate system due to its role in redistributing heat and freshwater between low and high latitudes, is anticipated to decline over the next century. The downwelling of surface waters in the subpolar North Atlantic that feeds the lower limb of AMOC is a vital yet vulnerable process. As revealed by previous theoretical and modelling work, the overall downstream densification along the boundary results in a significant boundary downwelling. Here, the density along the western boundary between Denmark Strait and Flemish Cap is reconstructed to provide a first observation-based description of the regional and seasonal distribution of this boundary-focused downwelling in the subpolar North Atlantic. This study not only provides valuable insights into how to improve existing ocean circulation theories of overturning but also contributes to a solid benchmark for evaluating how climate models simulate the sinking branch of the AMOC. 
PY 2022
PD APR
SO Geophysical Research Letters
SN 0094-8276
PU American Geophysical Union (AGU)
VL 49
IS 8
UT 000783186500001
DI 10.1029/2021GL097243
ID 87665
ER

EF