World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Impact of Oceanic Processes on the Carbon Cycle During the Last Termination : Volume 8, Issue 1 (20/01/2012)

By Bouttes, N.

Click here to view

Book Id: WPLBN0004006366
Format Type: PDF Article :
File Size: Pages 22
Reproduction Date: 2015

Title: Impact of Oceanic Processes on the Carbon Cycle During the Last Termination : Volume 8, Issue 1 (20/01/2012)  
Author: Bouttes, N.
Volume: Vol. 8, Issue 1
Language: English
Subject: Science, Climate, Past
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2012
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Paillard, D., Lourantou, A., Waelbroeck, C., Roche, D. M., Michel, E., Kageyama, M.,...Bopp, L. (2012). Impact of Oceanic Processes on the Carbon Cycle During the Last Termination : Volume 8, Issue 1 (20/01/2012). Retrieved from http://worldebooklibrary.org/


Description
Description: Laboratoire des Sciences du Climat et de l'Environnement, UMR8212, IPSL-CEA-CNRS-UVSQ, Centre d'Etudes de Saclay, Orme des Merisiers bat. 701, 91191 Gif Sur Yvette, France. During the last termination (from ~18 000 years ago to ~9000 years ago), the climate significantly warmed and the ice sheets melted. Simultaneously, atmospheric CO2 increased from ~190 ppm 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 Δ13C. 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 Δ13C appears to be highly sensitive to changes in the terrestrial biosphere, underlining the need to better constrain the vegetation evolution during the termination.


Summary
Impact of oceanic processes on the carbon cycle during the last termination

Excerpt
Anderson, J. B., Shipp, S. S., Lowe, A. L., Wellner, J. S., and Mosola, A. B.: The Antarctic Ice Sheet during the Last Glacial Maximum and its subsequent retreat history: a review, Quaternary Sci. Rev., 21, 49–70, doi:10.1016/S0277-3791(01)00083-X, 2002.; Archer, D.: Modeling the {C}alcite {L}ysocline, J. Geophys. Res., 96, 17037–17050, 1991.; Archer, D., Winguth, A., Lea, D., and Mahowald, N.: What caused the glacial/interglacial pCO2 cycles?, Rev. Geophys., 38, 159–189, 2000.; Berger, A. L.: Long-term variations of daily insolation and {Q}uaternary climatic changes, J. Atmos. Sci., 35, 2362–2368, 1978.; Archer, D. E., Martin, P. A., Milovich, J., Brovkin, V., Plattner, G.-K., and Ashendel, C.: Model sensitivity in the effect of {A}ntarctic sea ice and stratification on atmospheric pCO2, Paleoceanography, 18, 1012, doi:10.1029/2002PA000760, 2003.; Barker, S., Diz, P., Vautravers, M. J., Pike, J., Knorr, G., Hall, I. R., and Broecker, W. S.: Interhemispheric {A}tlantic seesaw response during the last deglaciation, Nature, 457, 1097–1102, doi:10.1038/nature07770, 2009.; Berger, A., Loutre, M. F., and Gallée, H.: Sensitivity of the LLN climate model to the astronomical and CO2 forcings over the last 200 ky, Clim. Dynam., 14, 615–629, doi:10.1007/s003820050245, 1998.; Berger, W. H.: Increase of carbon dioxide in the atmosphere during {D}eglaciation: the coral reef hypothesis, Naturwissenschaften, 69, 87–88, 1982.; Bird, M. I., Lloyd, J., and Farquhar, G. D.: Terrestrial carbon storage at the LGM, Nature, 371, 566, 1994.; Bopp, L., Kohfeld, K. E., Quéré, C. L., and Aumont, O.: Dust impact on marine biota and atmospheric {CO}2 during glacial periods, Paleoceanography, 18, 1046, doi:10.1029/2002PA000810, 2003.; Bouttes, N., Roche, D. M., and Paillard, D.: Impact of strong deep ocean stratification on the carbon cycle, Paleoceanography, 24, PA3203, doi:10.1029/2008PA001707, 2009.; Bouttes, N., Paillard, D., and Roche, D. M.: Impact of brine-induced stratification on the glacial carbon cycle, Clim. Past, 6, 575–589, doi:10.5194/cp-6-575-2010, 2010.; Bouttes, N., Paillard, D., Roche, D. M., Brovkin, V., and Bopp, L.: Last Glacial Maximum CO}2 and δ13{C successfully reconciled, Geophys. Res. Lett., 38, L02705, doi:10.1029/2010GL044499, 2011.; Broecker, W. S. and Peng, T.-H.: Tracers in the Sea, Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York, 1982.; Broecker, W. S. and Peng, T.-H.: The Role of {C}a{CO}3 Compensation in the {G}lacial to {I}nterglacial Atmospheric {CO}2 Change, Global Biogeochem. Cy., 1, 15–29, 1987.; Brovkin, V., Bendtsen, J., Claussen, M., Ganopolski, A., Kubatzki, C., Petoukhov, V., and Andreev, A.: Carbon cycle, vegetation, and climate dynamics in the {H}olocene: {E}xperiments with the {CLIMBER}-2 model, Global Biogeochem. Cy., 16, 1139, doi:10.1029/2001GB001662, 2002a.; Brovkin, V., Hofmann, M., Bendtsen, J., and Ganopolski, A.: Ocean biology could control atmospheric δ13{C} during glacial-i

 

Click To View

Additional Books


  • Ice Thinning, Upstream Advection, and No... (by )
  • Changing Correlation Structures of the N... (by )
  • A Millennial Multi-proxy Reconstruction ... (by )
  • Technical Note: Correcting for Signal At... (by )
  • Radiative Forcings for 28 Potential Arch... (by )
  • Monsoonal Response to Mid-holocene Orbit... (by )
  • Climatic Changes Between 20Th Century an... (by )
  • Predicting Pleistocene Climate from Vege... (by )
  • Glacier Response to North Atlantic Clima... (by )
  • The Extra-tropical NH Temperature in the... (by )
  • Pliocene to Pleistocene Climate and Envi... (by )
  • Climate and Vegetation Changes Around th... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.