FN Archimer Export Format
PT J
TI Early Eocene vigorous ocean overturning and its contribution to a warm Southern Ocean
BT 
AF Zhang, Yurui
   Huck, Thierry
   Lique, Camille
   Donnadieu, Yannick
   Ladant, Jean-Baptiste
   Rabineau, Marina
   Aslanian, Daniel
AS 1:1;2:7;3:1;4:2,3;5:4;6:5;7:6;
FF 1:PDG-ODE-LOPS-OH;2:;3:PDG-ODE-LOPS-OH;4:;5:;6:;7:PDG-REM-GM-LGS;
C1 Univ Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Brest, France
   Laboratoire des Sciences du Climat et de l’Environnement, LSCE-IPSL, CEA/CNRS/UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
   Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France
   Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
   CNRS, Univ Brest, Univ Bretagne Sud, Laboratoire Géosciences Océan (LGO, UMR6538), IUEM, Plouzané, France
   Ifremer, Unité de Recherche Géosciences Marines, Centre de Bretagne, Plouzané, France
   Univ Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Brest, France
C2 IFREMER, FRANCE
   CNRS, FRANCE
   UNIV AIX MARSEILLE, FRANCE
   UNIV MICHIGAN, USA
   CNRS, FRANCE
   IFREMER, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-ODE-LOPS-OH
   PDG-REM-GM-LGS
UM LOPS
   LGO
IN WOS Ifremer UPR
   WOS Ifremer UMR
   WOS Cotutelle UMR
   DOAJ
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
IF 4.295
TC 13
UR https://archimer.ifremer.fr/doc/00643/75529/76436.pdf
   https://archimer.ifremer.fr/doc/00643/75529/76437.pdf
   https://archimer.ifremer.fr/doc/00643/75529/76438.pdf
   https://archimer.ifremer.fr/doc/00643/75529/76439.pdf
LA English
DT Article
AB The early Eocene (∼55 Ma) was the warmest period of the Cenozoic and was most likely characterized by extremely high atmospheric CO2 concentrations. Here, we analyze simulations of the early Eocene performed with the IPSL-CM5A2 Earth system model, set up with paleogeographic reconstructions of this period from the DeepMIP project and with different levels of atmospheric CO2. When compared with proxy-based reconstructions, the simulations reasonably capture both the reconstructed amplitude and pattern of early Eocene sea surface temperature. A comparison with simulations of modern conditions allows us to explore the changes in ocean circulation and the resulting ocean meridional heat transport. At a CO2 level of 840 ppm, the early Eocene simulation is characterized by a strong abyssal overturning circulation in the Southern Hemisphere (40 Sv at 60∘ S), fed by deepwater formation in the three sectors of the Southern Ocean. Deep convection in the Southern Ocean is favored by the closed Drake and Tasmanian passages, which provide western boundaries for the buildup of strong subpolar gyres in the Weddell and Ross seas, in the middle of which convection develops. The strong overturning circulation, associated with subpolar gyres, sustains the poleward advection of saline subtropical water to the convective regions in the Southern Ocean, thereby maintaining deepwater formation. This salt–advection feedback mechanism is akin to that responsible for the present-day North Atlantic overturning circulation. The strong abyssal overturning circulation in the 55 Ma simulations primarily results in an enhanced poleward ocean heat transport by 0.3–0.7 PW in the Southern Hemisphere compared to modern conditions, reaching 1.7 PW southward at 20∘ S, and contributes to keeping the Southern Ocean and Antarctica warm in the Eocene. Simulations with different atmospheric CO2 levels show that ocean circulation and heat transport are relatively insensitive to CO2 doubling. 
PY 2020
PD JUN
SO Climate Of The Past
SN 1814-9324
PU Copernicus GmbH
VL 16
IS 4
UT 000551527500001
BP 1263
EP 1283
DI 10.5194/cp-16-1263-2020
ID 75529
ER

EF