Skill assessment of three earth system models with common marine biogeochemistry
Skill assessment of three earth system models with common marine biogeochemistry
We have assessed the ability of a common ocean biogeochemical model, PISCES, to match relevant modern data fields across a range of ocean circulation fields from three distinct Earth system models: IPSL-CM4-LOOP, IPSL-CM5A-LR and CNRM-CM5.1. The first of these Earth system models has contributed to the IPCC 4th assessment report, while the latter two are contributing to the ongoing IPCC 5th assessment report. These models differ with respect to their atmospheric component, ocean subgrid-scale physics and resolution. The simulated vertical distribution of biogeochemical tracers suffer from biases in ocean circulation and a poor representation of the sinking fluxes of matter. Nevertheless, differences between upper and deep ocean model skills significantly point to changes in the underlying model representations of ocean circulation. IPSL-CM5A-LR and CNRM-CM5.1 poorly represent deep-ocean circulation compared to IPSL-CM4-LOOP degrading the vertical distribution of biogeochemical tracers. However, their representations of surface wind, wind stress, mixed-layer depth and geostrophic circulations (e.g., Antarctic Circumpolar Current) have been improved compared to IPSL-CM4-LOOP. These improvements result in a better representation of large-scale structure of biogeochemical fields in the upper ocean. In particular, a deepening of 20–40 m of the summer mixed-layer depth allows to capture the 0–0.5 ?gChl L?1 concentrations class of surface chlorophyll in the Southern Ocean. Further improvements in the representation of the ocean mixed-layer and deep-ocean ventilation are needed for the next generations of models development to better simulate marine biogeochemistry. In order to better constrain ocean dynamics, we suggest that biogeochemical or passive tracer modules should be used routinely for both model development and model intercomparisons.
2549-2573
Séférian, Roland
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Bopp, Laurent
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Gehlen, Marion
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Orr, James C.
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Ethé, Christian
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Cadule, Patricia
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Aumont, Olivier
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Salas y Mélia, David
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Voldoire, Aurore
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Madec, Gurvan
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May 2013
Séférian, Roland
281466a7-fa1a-4b24-82cf-ee34e801792a
Bopp, Laurent
771de655-3caf-42ba-8231-40f17d4addc4
Gehlen, Marion
e4883d9b-b726-46b9-abcd-c2915e5cee51
Orr, James C.
46a466b9-a3e6-4f5d-82a1-0dbd848536fb
Ethé, Christian
1dad00c0-48fe-4ea4-839b-6b4fc2d3bcf2
Cadule, Patricia
1f254547-6f7b-48a6-ac71-13d23f7317eb
Aumont, Olivier
6ea5af9d-4c27-42d9-9ba7-749729efa72f
Salas y Mélia, David
4a745792-3881-4132-a854-01d9b9fe5a8a
Voldoire, Aurore
32854fb3-d7bd-4ba6-a07a-149991b57f27
Madec, Gurvan
ffb28deb-4bbd-4a4c-914f-492f813e4864
Séférian, Roland, Bopp, Laurent, Gehlen, Marion, Orr, James C., Ethé, Christian, Cadule, Patricia, Aumont, Olivier, Salas y Mélia, David, Voldoire, Aurore and Madec, Gurvan
(2013)
Skill assessment of three earth system models with common marine biogeochemistry.
Climate Dynamics, 40 (9-10), .
(doi:10.1007/s00382-012-1362-8).
Abstract
We have assessed the ability of a common ocean biogeochemical model, PISCES, to match relevant modern data fields across a range of ocean circulation fields from three distinct Earth system models: IPSL-CM4-LOOP, IPSL-CM5A-LR and CNRM-CM5.1. The first of these Earth system models has contributed to the IPCC 4th assessment report, while the latter two are contributing to the ongoing IPCC 5th assessment report. These models differ with respect to their atmospheric component, ocean subgrid-scale physics and resolution. The simulated vertical distribution of biogeochemical tracers suffer from biases in ocean circulation and a poor representation of the sinking fluxes of matter. Nevertheless, differences between upper and deep ocean model skills significantly point to changes in the underlying model representations of ocean circulation. IPSL-CM5A-LR and CNRM-CM5.1 poorly represent deep-ocean circulation compared to IPSL-CM4-LOOP degrading the vertical distribution of biogeochemical tracers. However, their representations of surface wind, wind stress, mixed-layer depth and geostrophic circulations (e.g., Antarctic Circumpolar Current) have been improved compared to IPSL-CM4-LOOP. These improvements result in a better representation of large-scale structure of biogeochemical fields in the upper ocean. In particular, a deepening of 20–40 m of the summer mixed-layer depth allows to capture the 0–0.5 ?gChl L?1 concentrations class of surface chlorophyll in the Southern Ocean. Further improvements in the representation of the ocean mixed-layer and deep-ocean ventilation are needed for the next generations of models development to better simulate marine biogeochemistry. In order to better constrain ocean dynamics, we suggest that biogeochemical or passive tracer modules should be used routinely for both model development and model intercomparisons.
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Published date: May 2013
Organisations:
Marine Systems Modelling
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Local EPrints ID: 362987
URI: http://eprints.soton.ac.uk/id/eprint/362987
ISSN: 0930-7575
PURE UUID: 8a852df7-0bb8-427f-a73f-1dea81560bc8
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Date deposited: 10 Mar 2014 15:23
Last modified: 14 Mar 2024 16:17
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Contributors
Author:
Roland Séférian
Author:
Laurent Bopp
Author:
Marion Gehlen
Author:
James C. Orr
Author:
Christian Ethé
Author:
Patricia Cadule
Author:
Olivier Aumont
Author:
David Salas y Mélia
Author:
Aurore Voldoire
Author:
Gurvan Madec
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