Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors
A new framework is presented for analysing the proximate causes of model Arctic sea ice biases, demonstrated with the CMIP5 model HadGEM2-ES (Hadley Centre Global Environment Model version 2 – Earth System). In this framework the Arctic sea ice volume is treated as a consequence of the integrated su...
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ftcopernicus:oai:publications.copernicus.org:tc67443 2023-05-15T13:11:24+02:00 Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors West, Alex Collins, Mat Blockley, Ed Ridley, Jeff Bodas-Salcedo, Alejandro 2019-07-19 application/pdf https://doi.org/10.5194/tc-13-2001-2019 https://tc.copernicus.org/articles/13/2001/2019/ eng eng doi:10.5194/tc-13-2001-2019 https://tc.copernicus.org/articles/13/2001/2019/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-13-2001-2019 2020-07-20T16:22:44Z A new framework is presented for analysing the proximate causes of model Arctic sea ice biases, demonstrated with the CMIP5 model HadGEM2-ES (Hadley Centre Global Environment Model version 2 – Earth System). In this framework the Arctic sea ice volume is treated as a consequence of the integrated surface energy balance, via the volume balance. A simple model allows the local dependence of the surface flux on specific model variables to be described as a function of time and space. When these are combined with reference datasets, it is possible to estimate the surface flux bias induced by the model bias in each variable. The method allows the role of the surface albedo and ice thickness–growth feedbacks in sea ice volume balance biases to be quantified along with the roles of model bias in variables not directly related to the sea ice volume. It shows biases in the HadGEM2-ES sea ice volume simulation to be due to a bias in spring surface melt onset date, partly countered by a bias in winter downwelling longwave radiation. The framework is applicable in principle to any model and has the potential to greatly improve understanding of the reasons for ensemble spread in the modelled sea ice state. A secondary finding is that observational uncertainty is the largest cause of uncertainty in the induced surface flux bias calculation. Text albedo Arctic Sea ice Copernicus Publications: E-Journals Arctic The Cryosphere 13 7 2001 2022 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
A new framework is presented for analysing the proximate causes of model Arctic sea ice biases, demonstrated with the CMIP5 model HadGEM2-ES (Hadley Centre Global Environment Model version 2 – Earth System). In this framework the Arctic sea ice volume is treated as a consequence of the integrated surface energy balance, via the volume balance. A simple model allows the local dependence of the surface flux on specific model variables to be described as a function of time and space. When these are combined with reference datasets, it is possible to estimate the surface flux bias induced by the model bias in each variable. The method allows the role of the surface albedo and ice thickness–growth feedbacks in sea ice volume balance biases to be quantified along with the roles of model bias in variables not directly related to the sea ice volume. It shows biases in the HadGEM2-ES sea ice volume simulation to be due to a bias in spring surface melt onset date, partly countered by a bias in winter downwelling longwave radiation. The framework is applicable in principle to any model and has the potential to greatly improve understanding of the reasons for ensemble spread in the modelled sea ice state. A secondary finding is that observational uncertainty is the largest cause of uncertainty in the induced surface flux bias calculation. |
format |
Text |
author |
West, Alex Collins, Mat Blockley, Ed Ridley, Jeff Bodas-Salcedo, Alejandro |
spellingShingle |
West, Alex Collins, Mat Blockley, Ed Ridley, Jeff Bodas-Salcedo, Alejandro Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
author_facet |
West, Alex Collins, Mat Blockley, Ed Ridley, Jeff Bodas-Salcedo, Alejandro |
author_sort |
West, Alex |
title |
Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
title_short |
Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
title_full |
Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
title_fullStr |
Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
title_full_unstemmed |
Induced surface fluxes: a new framework for attributing Arctic sea ice volume balance biases to specific model errors |
title_sort |
induced surface fluxes: a new framework for attributing arctic sea ice volume balance biases to specific model errors |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-2001-2019 https://tc.copernicus.org/articles/13/2001/2019/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
albedo Arctic Sea ice |
genre_facet |
albedo Arctic Sea ice |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-13-2001-2019 https://tc.copernicus.org/articles/13/2001/2019/ |
op_doi |
https://doi.org/10.5194/tc-13-2001-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
7 |
container_start_page |
2001 |
op_container_end_page |
2022 |
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1766247275508531200 |