FN Archimer Export Format
PT J
TI Impact of oceanic processes on the carbon cycle during the last termination
BT 
AF BOUTTES, N.
   PAILLARD, D.
   ROCHE, D. M.
   WAELBROECK, C.
   KAGEYAMA, M.
   LOURANTOU, A.
   MICHEL, E.
   BOPP, L.
AS 1:1,2;2:1;3:1,3;4:1;5:1;6:4;7:1;8:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 IPSL CEA CNRS UVSQ, Ctr Etud Saclay, Lab Sci Climat & Environm, UMR8212, F-91191 Gif Sur Yvette, France.
   Univ Reading, Dept Meteorol, NCAS Climate, Reading RG6 6BB, Berks, England.
   Vrije Univ Amsterdam, Sect Climate Change & Landscape Dynam, Fac Earth & Life Sci, NL-1081 HV Amsterdam, Netherlands.
   Univ Paris 06, LOCEAN, Paris, France.
C2 IPSL, FRANCE
   UNIV READING, UK
   UNIV VRIJE AMSTERDAM, NETHERLANDS
   UNIV PARIS 06, FRANCE
IN DOAJ
IF 3.56
TC 25
UR https://archimer.ifremer.fr/doc/00214/32514/31004.pdf
LA English
DT Article
CR VT 90 / SOUC
BO Marion Dufresne
AB During the last termination (from similar to 18 000 years ago to similar to 9000 years ago), the climate significantly warmed and the ice sheets melted. Simultaneously, atmospheric CO2 increased from similar to 190 ppm to similar to 260 ppm. Although this CO2 rise plays an important role in the deglacial warming, the reasons for its evolution are difficult to explain. Only box models have been used to run transient simulations of this carbon cycle transition, but by forcing the model with data constrained scenarios of the evolution of temperature, sea level, sea ice, NADW formation, Southern Ocean vertical mixing and biological carbon pump. More complex models (including GCMs) have investigated some of these mechanisms but they have only been used to try and explain LGM versus present day steady-state climates. In this study we use a coupled climate-carbon model of intermediate complexity to explore the role of three oceanic processes in transient simulations: the sinking of brines, stratification-dependent diffusion and iron fertilization. Carbonate compensation is accounted for in these simulations. We show that neither iron fertilization nor the sinking of brines alone can account for the evolution of CO2, and that only the combination of the sinking of brines and interactive diffusion can simultaneously simulate the increase in deep Southern Ocean delta C-13. The scenario that agrees best with the data takes into account all mechanisms and favours a rapid cessation of the sinking of brines around 18 000 years ago, when the Antarctic ice sheet extent was at its maximum. In this scenario, we make the hypothesis that sea ice formation was then shifted to the open ocean where the salty water is quickly mixed with fresher water, which prevents deep sinking of salty water and therefore breaks down the deep stratification and releases carbon from the abyss. Based on this scenario, it is possible to simulate both the amplitude and timing of the long-term CO2 increase during the last termination in agreement with ice core data. The atmospheric delta C-13 appears to be highly sensitive to changes in the terrestrial biosphere, underlining the need to better constrain the vegetation evolution during the termination.
PY 2012
SO Climate Of The Past
SN 1814-9324
PU Copernicus Gesellschaft Mbh
VL 8
IS 1
UT 000300878100010
BP 149
EP 170
DI 10.5194/cp-8-149-2012
ID 32514
ER

EF