Sensitivity of deep ocean biases to horizontal resolution in prototype CMIP6 simulations with AWI-CM1.0
Models from phase 5 of the Coupled Model Intercomparison 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...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00001489 2023-05-15T13:15:51+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 electronic https://doi.org/10.5194/gmd-12-2635-2019 https://noa.gwlb.de/receive/cop_mods_00001489 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00001450/gmd-12-2635-2019.pdf https://gmd.copernicus.org/articles/12/2635/2019/gmd-12-2635-2019.pdf eng eng Copernicus Publications Geoscientific Model Development -- http://www.bibliothek.uni-regensburg.de/ezeit/?2456725 -- http://www.geosci-model-dev.net/ -- 1991-9603 https://doi.org/10.5194/gmd-12-2635-2019 https://noa.gwlb.de/receive/cop_mods_00001489 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00001450/gmd-12-2635-2019.pdf https://gmd.copernicus.org/articles/12/2635/2019/gmd-12-2635-2019.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2019 ftnonlinearchiv https://doi.org/10.5194/gmd-12-2635-2019 2022-02-08T23:01:48Z Models from phase 5 of the Coupled Model Intercomparison 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 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, which employs a sea ice–ocean model component 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 improvements 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 regions 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 outcropping 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 perform 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 Alfred Wegener Institute North Atlantic Sea ice Southern Ocean Niedersächsisches Online-Archiv NOA Southern Ocean Geoscientific Model Development 12 7 2635 2656 |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung 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 |
topic_facet |
article Verlagsveröffentlichung |
description |
Models from phase 5 of the Coupled Model Intercomparison 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 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, which employs a sea ice–ocean model component 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 improvements 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 regions 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 outcropping 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 perform 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 |
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://doi.org/10.5194/gmd-12-2635-2019 https://noa.gwlb.de/receive/cop_mods_00001489 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00001450/gmd-12-2635-2019.pdf https://gmd.copernicus.org/articles/12/2635/2019/gmd-12-2635-2019.pdf |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Alfred Wegener Institute North Atlantic Sea ice Southern Ocean |
genre_facet |
Alfred Wegener Institute North Atlantic Sea ice Southern Ocean |
op_relation |
Geoscientific Model Development -- http://www.bibliothek.uni-regensburg.de/ezeit/?2456725 -- http://www.geosci-model-dev.net/ -- 1991-9603 https://doi.org/10.5194/gmd-12-2635-2019 https://noa.gwlb.de/receive/cop_mods_00001489 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00001450/gmd-12-2635-2019.pdf https://gmd.copernicus.org/articles/12/2635/2019/gmd-12-2635-2019.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/gmd-12-2635-2019 |
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Geoscientific Model Development |
container_volume |
12 |
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7 |
container_start_page |
2635 |
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2656 |
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