An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation
The key physical parameters for the "eb_go_gs" configuration of version 2.7.4 of GENIE, an Earth system model of intermediate complexity (EMIC), are tuned using a multi-objective genetic algorithm. An ensemble of 90 parameter sets is tuned using two ocean and two atmospheric state variable...
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ftdoajarticles:oai:doaj.org/article:0eec7052a980407cbf63830cfcdd4bc5 2023-05-15T18:18:08+02:00 An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation R. Marsh A. Sóbester E. E. Hart K. I. C. Oliver N. R. Edwards S. J. Cox 2013-10-01T00:00:00Z https://doi.org/10.5194/gmd-6-1729-2013 https://doaj.org/article/0eec7052a980407cbf63830cfcdd4bc5 EN eng Copernicus Publications http://www.geosci-model-dev.net/6/1729/2013/gmd-6-1729-2013.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-6-1729-2013 1991-959X 1991-9603 https://doaj.org/article/0eec7052a980407cbf63830cfcdd4bc5 Geoscientific Model Development, Vol 6, Iss 5, Pp 1729-1744 (2013) Geology QE1-996.5 article 2013 ftdoajarticles https://doi.org/10.5194/gmd-6-1729-2013 2022-12-31T09:08:57Z The key physical parameters for the "eb_go_gs" configuration of version 2.7.4 of GENIE, an Earth system model of intermediate complexity (EMIC), are tuned using a multi-objective genetic algorithm. An ensemble of 90 parameter sets is tuned using two ocean and two atmospheric state variables as targets. These are "Pareto-optimal", representing a range of trade-offs between the four tuning targets. For the leading five parameter sets, simulations are evaluated alongside a simulation with untuned "default" parameters, comparing selected variables and diagnostics that describe the state of the atmosphere, ocean and sea ice. Further experiments are undertaken with these selected parameter sets to compare equilibrium climate sensitivities and transient climate responses. The pattern of warming under doubled CO 2 is strongly shaped by changes in the Atlantic meridional overturning circulation (AMOC), while the pattern and rate of warming under rising CO 2 is closely linked to changing sea ice extent. One of the five tuned parameter sets is identified as marginally optimal, and the objective function (error) landscape is further analysed in the vicinity of the tuned values of this parameter set. "Cliffs" along some dimensions motivate closer inspection of corresponding variations in the AMOC. This reveals that bifurcations in the AMOC are highly sensitive to parameters that are not typically associated with MOC stability. Specifically, the state of the AMOC is sensitive to parameters governing the wind-driven circulation and atmospheric heat transport. For the GENIE configuration presented here, the marginally optimal parameter set is recommended for single simulations, although the leading five parameter sets may be used in ensemble mode to admit a constrained degree of parametric uncertainty in climate prediction. Article in Journal/Newspaper Sea ice Directory of Open Access Journals: DOAJ Articles Geoscientific Model Development 6 5 1729 1744 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
topic |
Geology QE1-996.5 |
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Geology QE1-996.5 R. Marsh A. Sóbester E. E. Hart K. I. C. Oliver N. R. Edwards S. J. Cox An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
topic_facet |
Geology QE1-996.5 |
description |
The key physical parameters for the "eb_go_gs" configuration of version 2.7.4 of GENIE, an Earth system model of intermediate complexity (EMIC), are tuned using a multi-objective genetic algorithm. An ensemble of 90 parameter sets is tuned using two ocean and two atmospheric state variables as targets. These are "Pareto-optimal", representing a range of trade-offs between the four tuning targets. For the leading five parameter sets, simulations are evaluated alongside a simulation with untuned "default" parameters, comparing selected variables and diagnostics that describe the state of the atmosphere, ocean and sea ice. Further experiments are undertaken with these selected parameter sets to compare equilibrium climate sensitivities and transient climate responses. The pattern of warming under doubled CO 2 is strongly shaped by changes in the Atlantic meridional overturning circulation (AMOC), while the pattern and rate of warming under rising CO 2 is closely linked to changing sea ice extent. One of the five tuned parameter sets is identified as marginally optimal, and the objective function (error) landscape is further analysed in the vicinity of the tuned values of this parameter set. "Cliffs" along some dimensions motivate closer inspection of corresponding variations in the AMOC. This reveals that bifurcations in the AMOC are highly sensitive to parameters that are not typically associated with MOC stability. Specifically, the state of the AMOC is sensitive to parameters governing the wind-driven circulation and atmospheric heat transport. For the GENIE configuration presented here, the marginally optimal parameter set is recommended for single simulations, although the leading five parameter sets may be used in ensemble mode to admit a constrained degree of parametric uncertainty in climate prediction. |
format |
Article in Journal/Newspaper |
author |
R. Marsh A. Sóbester E. E. Hart K. I. C. Oliver N. R. Edwards S. J. Cox |
author_facet |
R. Marsh A. Sóbester E. E. Hart K. I. C. Oliver N. R. Edwards S. J. Cox |
author_sort |
R. Marsh |
title |
An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
title_short |
An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
title_full |
An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
title_fullStr |
An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
title_full_unstemmed |
An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation |
title_sort |
optimally tuned ensemble of the "eb_go_gs" configuration of genie: parameter sensitivity and bifurcations in the atlantic overturning circulation |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/gmd-6-1729-2013 https://doaj.org/article/0eec7052a980407cbf63830cfcdd4bc5 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Geoscientific Model Development, Vol 6, Iss 5, Pp 1729-1744 (2013) |
op_relation |
http://www.geosci-model-dev.net/6/1729/2013/gmd-6-1729-2013.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-6-1729-2013 1991-959X 1991-9603 https://doaj.org/article/0eec7052a980407cbf63830cfcdd4bc5 |
op_doi |
https://doi.org/10.5194/gmd-6-1729-2013 |
container_title |
Geoscientific Model Development |
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6 |
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5 |
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1729 |
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1744 |
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