Lhardy, F, Bouttes, N, Roche, DM et al. (15 more authors) (2021) A First Intercomparison of the Simulated LGM Carbon Results Within PMIP-Carbon: Role of the Ocean Boundary Conditions. Paleoceanography and Paleoclimatology, 36 (10). e2021PA004302. ISSN 2572-4525
Abstract
Model intercomparison studies of coupled carbon-climate simulations have the potential to improve our understanding of the processes explaining the pCO₂ drawdown at the Last Glacial Maximum (LGM) and to identify related model biases. Models participating in the Paleoclimate Modeling Intercomparison Project (PMIP) now frequently include the carbon cycle. The ongoing PMIP-carbon project provides the first opportunity to conduct multimodel comparisons of simulated carbon content for the LGM time window. However, such a study remains challenging due to differing implementation of ocean boundary conditions (e.g., bathymetry and coastlines reflecting the low sea level) and to various associated adjustments of biogeochemical variables (i.e., alkalinity, nutrients, dissolved inorganic carbon). After assessing the ocean volume of PMIP models at the pre-industrial and LGM, we investigate the impact of these modeling choices on the simulated carbon at the global scale, using both PMIP-carbon model outputs and sensitivity tests with the iLOVECLIM model. We show that the carbon distribution in reservoirs is significantly affected by the choice of ocean boundary conditions in iLOVECLIM. In particular, our simulations demonstrate a ~ 250 GtC effect of an alkalinity adjustment on carbon sequestration in the ocean. Finally, we observe that PMIP-carbon models with a freely evolving CO₂ and no additional glacial mechanisms do not simulate the pCO₂ drawdown at the LGM (with concentrations as high as 313, 331, and 315 ppm), especially if they use a low ocean volume. Our findings suggest that great care should be taken on accounting for large bathymetry changes in models including the carbon cycle.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021. American Geophysical Union. All Rights Reserved. This is the peer reviewed version of the following article: Lhardy, F., Bouttes, N., Roche, D. M., Abe-Ouchi, A., Chase, Z., Crichton, K. A., et al. (2021). A first intercomparison of the simulated LGM carbon results within PMIP-carbon: Role of the ocean boundary conditions. Paleoceanography and Paleoclimatology, 36, e2021PA004302, which has been published in final form at https://doi.org/10.1029/2021PA004302. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | climate models; glacial-interglacial cycles; carbon cycle; atmospheric CO2; ocean volume; alkalinity |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC UNSPECIFIED NERC (Natural Environment Research Council) NE/K008536/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 30 Sep 2021 13:08 |
Last Modified: | 29 Mar 2022 00:38 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1029/2021pa004302 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:178629 |