Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0
Models from phase 5 of the Coupled Model Inter-comparison Project (CMIP5) show substantial biases in the deep ocean that are larger than the level of natural variability and the response to enhanced greenhouse gas concentrations. Here, we analyze the influence of horizontal resolution in a hierarchy...
Published in: | Geoscientific Model Development |
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2019
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Online Access: | https://epic.awi.de/id/eprint/49950/ https://epic.awi.de/id/eprint/49950/1/gmd-12-2635-2019-4.pdf https://doi.org/10.5194/gmd-12-2635-2019 https://hdl.handle.net/10013/epic.60ba31c2-007e-47f9-ad75-644597b95e58 https://hdl.handle.net/ |
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ftawi:oai:epic.awi.de:49950 2023-05-15T17:36:42+02:00 Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 Rackow, Thomas Sein, Dmitry V. Semmler, Tido Danilov, Sergey Koldunov, Nikolay V. Sidorenko, Dmitry Wang, Qiang Jung, Thomas 2019-07-05 application/pdf https://epic.awi.de/id/eprint/49950/ https://epic.awi.de/id/eprint/49950/1/gmd-12-2635-2019-4.pdf https://doi.org/10.5194/gmd-12-2635-2019 https://hdl.handle.net/10013/epic.60ba31c2-007e-47f9-ad75-644597b95e58 https://hdl.handle.net/ unknown Copernicus Publications https://epic.awi.de/id/eprint/49950/1/gmd-12-2635-2019-4.pdf https://hdl.handle.net/ Rackow, T. orcid:0000-0002-5468-575X , Sein, D. V. orcid:0000-0002-1190-3622 , Semmler, T. orcid:0000-0002-2254-4901 , Danilov, S. orcid:0000-0001-8098-182X , Koldunov, N. V. orcid:0000-0002-3365-8146 , Sidorenko, D. orcid:0000-0001-8579-6068 , Wang, Q. orcid:0000-0002-2704-5394 and Jung, T. orcid:0000-0002-2651-1293 (2019) Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 , Geoscientific Model Development, 12 (7), pp. 2635-2656 . doi:10.5194/gmd-12-2635-2019 <https://doi.org/10.5194/gmd-12-2635-2019> , hdl:10013/epic.60ba31c2-007e-47f9-ad75-644597b95e58 info:eu-repo/semantics/openAccess EPIC3Geoscientific Model Development, Copernicus Publications, 12(7), pp. 2635-2656, ISSN: 1991-9603 Article isiRev info:eu-repo/semantics/article 2019 ftawi https://doi.org/10.5194/gmd-12-2635-2019 2021-12-24T15:44:50Z Models from phase 5 of the Coupled Model Inter-comparison Project (CMIP5) show substantial biases in the deep ocean that are larger than the level of natural variability and the response to enhanced greenhouse gas concentrations. Here, we analyze the influence of horizontal resolution in a hierarchy of five multi-resolution simulations with the AWI Climate Model (AWI-CM), the climate model used at the Al-fred Wegener Institute, Helmholtz Centre for Polar and Ma-rine Research, which employs a sea ice–ocean model com-ponent formulated on unstructured meshes. The ocean grid sizes considered range from a nominal resolution of ∼ 1◦ (CMIP5 type) up to locally eddy resolving. We show that increasing ocean resolution locally to resolve ocean eddies leads to reductions in deep ocean biases, although these im-provements are not strictly monotonic for the five different ocean grids. A detailed diagnosis of the simulations allows to identify the origins of the biases. We find that two key re-gions at the surface are responsible for the development of the deep bias in the Atlantic Ocean: the northeastern North Atlantic and the region adjacent to the Strait of Gibraltar. Furthermore, the Southern Ocean density structure is equally improved with locally explicitly resolved eddies compared to parameterized eddies. Part of the bias reduction can be traced back towards improved surface biases over outcrop-ping regions, which are in contact with deeper ocean layers along isopycnal surfaces. Our prototype simulations provide guidance for the optimal choice of ocean grids for AWI-CM to be used in the final runs for phase 6 of CMIP (CMIP6) and for the related flagship simulations in the High Resolution Model Intercomparison Project (HighResMIP). Quite remarkably, retaining resolution only in areas of high eddy activity along with excellent scalability characteristics of the unstructured-mesh sea ice–ocean model enables us to per-form the multi-centennial climate simulations needed in a CMIP context at (locally) eddy-resolving resolution with a throughput of 5–6 simulated years per day. Article in Journal/Newspaper North Atlantic Sea ice Southern Ocean Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Southern Ocean Geoscientific Model Development 12 7 2635 2656 |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Models from phase 5 of the Coupled Model Inter-comparison Project (CMIP5) show substantial biases in the deep ocean that are larger than the level of natural variability and the response to enhanced greenhouse gas concentrations. Here, we analyze the influence of horizontal resolution in a hierarchy of five multi-resolution simulations with the AWI Climate Model (AWI-CM), the climate model used at the Al-fred Wegener Institute, Helmholtz Centre for Polar and Ma-rine Research, which employs a sea ice–ocean model com-ponent formulated on unstructured meshes. The ocean grid sizes considered range from a nominal resolution of ∼ 1◦ (CMIP5 type) up to locally eddy resolving. We show that increasing ocean resolution locally to resolve ocean eddies leads to reductions in deep ocean biases, although these im-provements are not strictly monotonic for the five different ocean grids. A detailed diagnosis of the simulations allows to identify the origins of the biases. We find that two key re-gions at the surface are responsible for the development of the deep bias in the Atlantic Ocean: the northeastern North Atlantic and the region adjacent to the Strait of Gibraltar. Furthermore, the Southern Ocean density structure is equally improved with locally explicitly resolved eddies compared to parameterized eddies. Part of the bias reduction can be traced back towards improved surface biases over outcrop-ping regions, which are in contact with deeper ocean layers along isopycnal surfaces. Our prototype simulations provide guidance for the optimal choice of ocean grids for AWI-CM to be used in the final runs for phase 6 of CMIP (CMIP6) and for the related flagship simulations in the High Resolution Model Intercomparison Project (HighResMIP). Quite remarkably, retaining resolution only in areas of high eddy activity along with excellent scalability characteristics of the unstructured-mesh sea ice–ocean model enables us to per-form the multi-centennial climate simulations needed in a CMIP context at (locally) eddy-resolving resolution with a throughput of 5–6 simulated years per day. |
format |
Article in Journal/Newspaper |
author |
Rackow, Thomas Sein, Dmitry V. Semmler, Tido Danilov, Sergey Koldunov, Nikolay V. Sidorenko, Dmitry Wang, Qiang Jung, Thomas |
spellingShingle |
Rackow, Thomas Sein, Dmitry V. Semmler, Tido Danilov, Sergey Koldunov, Nikolay V. Sidorenko, Dmitry Wang, Qiang Jung, Thomas Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
author_facet |
Rackow, Thomas Sein, Dmitry V. Semmler, Tido Danilov, Sergey Koldunov, Nikolay V. Sidorenko, Dmitry Wang, Qiang Jung, Thomas |
author_sort |
Rackow, Thomas |
title |
Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
title_short |
Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
title_full |
Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
title_fullStr |
Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
title_full_unstemmed |
Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 |
title_sort |
sensitivity of deep ocean biases to horizontal resolution in prototype cmip6 simulations with awi-cm1.0 |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://epic.awi.de/id/eprint/49950/ https://epic.awi.de/id/eprint/49950/1/gmd-12-2635-2019-4.pdf https://doi.org/10.5194/gmd-12-2635-2019 https://hdl.handle.net/10013/epic.60ba31c2-007e-47f9-ad75-644597b95e58 https://hdl.handle.net/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Sea ice Southern Ocean |
genre_facet |
North Atlantic Sea ice Southern Ocean |
op_source |
EPIC3Geoscientific Model Development, Copernicus Publications, 12(7), pp. 2635-2656, ISSN: 1991-9603 |
op_relation |
https://epic.awi.de/id/eprint/49950/1/gmd-12-2635-2019-4.pdf https://hdl.handle.net/ Rackow, T. orcid:0000-0002-5468-575X , Sein, D. V. orcid:0000-0002-1190-3622 , Semmler, T. orcid:0000-0002-2254-4901 , Danilov, S. orcid:0000-0001-8098-182X , Koldunov, N. V. orcid:0000-0002-3365-8146 , Sidorenko, D. orcid:0000-0001-8579-6068 , Wang, Q. orcid:0000-0002-2704-5394 and Jung, T. orcid:0000-0002-2651-1293 (2019) Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0 , Geoscientific Model Development, 12 (7), pp. 2635-2656 . doi:10.5194/gmd-12-2635-2019 <https://doi.org/10.5194/gmd-12-2635-2019> , hdl:10013/epic.60ba31c2-007e-47f9-ad75-644597b95e58 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/gmd-12-2635-2019 |
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Geoscientific Model Development |
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