FN Archimer Export Format
PT J
TI Significance of Diapycnal Mixing Within the Atlantic Meridional Overturning Circulation
BT 
AF Cimoli, Laura
   Mashayek, Ali
   Johnson, Helen L.
   Marshall, David P.
   Naveira Garabato, Alberto C.
   Whalen, Caitlin B.
   Vic, Clement
   de Lavergne, Casimir
   Alford, Matthew H.
   MacKinnon, Jennifer A.
   Talley, Lynne D.
AS 1:1,2,3;2:4;3:5;4:3;5:6;6:7;7:8;8:9;9:2;10:2;11:2;
FF 1:;2:;3:;4:;5:;6:;7:PDG-ODE-LOPS-OH;8:;9:;10:;11:;
C1 Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge, UK
   Scripps Institution of Oceanography University of California San Diego CA La Jolla, USA
   Department of Physics University of Oxford Oxford, UK
   Department of Earth Sciences University of Cambridge Cambridge,UK
   Department of Earth Sciences University of Oxford Oxford, UK
   School of Ocean and Earth Science University of Southampton Southampton ,UK
   Applied Physics Laboratory University of Washington WA Seattle, USA
   Laboratoire d’Océanographie Physique et Spatiale University of Brest CNRS IRD Ifremer Plouzané ,France
   LOCEAN Laboratory Sorbonne Université‐CNRS‐IRD‐MNHN Paris ,France
C2 UNIV CAMBRIDGE, UK
   UNIV CALIF SAN DIEGO, USA
   UNIV OXFORD, UK
   UNIV CAMBRIDGE, UK
   UNIV OXFORD, UK
   UNIV SOUTHAMPTON, UK
   UNIV WASHINGTON, USA
   IFREMER, FRANCE
   UNIV SORBONNE, FRANCE
SI BREST
SE PDG-ODE-LOPS-OH
UM LOPS
IN WOS Ifremer UMR
   DOAJ
   copubli-france
   copubli-europe
   copubli-univ-france
   copubli-int-hors-europe
IF 8.4
TC 5
UR https://archimer.ifremer.fr/doc/00825/93663/100441.pdf
   https://archimer.ifremer.fr/doc/00825/93663/100442.pdf
   https://archimer.ifremer.fr/doc/00825/93663/100443.pdf
   https://archimer.ifremer.fr/doc/00825/93663/100444.pdf
   https://archimer.ifremer.fr/doc/00825/93663/100445.pdf
LA English
DT Article
DE ;diapycnal mixing;Atlantic Ocean;tracer ventilation
AB Diapycnal mixing shapes the distribution of climatically important tracers, such as heat and carbon, as these are carried by dense water masses in the ocean interior. Here, we analyze a suite of observation-based estimates of diapycnal mixing to assess its role within the Atlantic Meridional Overturning Circulation (AMOC). The rate of water mass transformation in the Atlantic Ocean's interior shows that there is a robust buoyancy increase in the North Atlantic Deep Water (NADW, neutral density γn ≃ 27.6–28.15), with a diapycnal circulation of 0.5–8 Sv between 48°N and 32°S in the Atlantic Ocean. Moreover, tracers within the southward-flowing NADW may undergo a substantial diapycnal transfer, equivalent to a vertical displacement of hundreds of meters in the vertical. This result, confirmed with a zonally averaged numerical model of the AMOC, indicates that mixing can alter where tracers upwell in the Southern Ocean, ultimately affecting their global pathways and ventilation timescales. These results point to the need for a realistic mixing representation in climate models in order to understand and credibly project the ongoing climate change. Key Points The cross-density mixing of water and tracers is quantified from observation-based estimates and numerical simulations in the Atlantic Ocean A net 0.5–8 Sv of North Atlantic Deep Water upwells diapycnally in the Atlantic Ocean (48°N–32°S), comprised of larger regional up/downwelling fluxes Tracer mixing in the deep Atlantic Ocean can significantly modify pathways and ventilation rates of tracers upwelling in the Southern Ocean Plain Language Summary The Atlantic Ocean meridional overturning circulation plays a key role in regulating the global heat and carbon budgets by inter-hemispheric transport of anthropogenic and natural tracers as well as water masses. While most of this transport occurs along nearly horizontal density surfaces in the ocean interior, vertical transport across density levels is key to bringing deep waters back to the surface. Such cross-density transport is facilitated mainly by the internal waves breaking into turbulence and near boundary processes. This work employs a host of observation-based estimates of turbulence in the Atlantic Ocean to (a) better quantify the contribution of cross-density mixing to the inter-hemispheric Atlantic circulation, and (b) discuss the potential implications for pathways and residence times of tracers carried from the North Atlantic to the Southern Ocean. This work calls for a more careful representation of turbulence-induced vertical mixing within the Atlantic Ocean in climate models to better understand and project the ongoing climate change. 
PY 2023
PD APR
SO Agu Advances
SN 2576-604X
PU American Geophysical Union (AGU)
VL 4
IS 2
UT 000947335500001
DI 10.1029/2022AV000800
ID 93663
ER

EF