Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt
Arctic sea ice is declining rapidly, but predictions of its future loss are made difficult by the large spread both in present-day and in future sea ice area and volume; hence, there is a need to better understand the drivers of model spread in sea ice state. Here we present a framework for understa...
Published in: | The Cryosphere |
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Online Access: | https://doi.org/10.5194/tc-16-4013-2022 https://tc.copernicus.org/articles/16/4013/2022/ |
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ftcopernicus:oai:publications.copernicus.org:tc99065 2023-05-15T13:11:42+02:00 Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt West, Alex Blockley, Edward Collins, Matthew 2022-10-07 application/pdf https://doi.org/10.5194/tc-16-4013-2022 https://tc.copernicus.org/articles/16/4013/2022/ eng eng doi:10.5194/tc-16-4013-2022 https://tc.copernicus.org/articles/16/4013/2022/ eISSN: 1994-0424 Text 2022 ftcopernicus https://doi.org/10.5194/tc-16-4013-2022 2022-10-10T16:22:41Z Arctic sea ice is declining rapidly, but predictions of its future loss are made difficult by the large spread both in present-day and in future sea ice area and volume; hence, there is a need to better understand the drivers of model spread in sea ice state. Here we present a framework for understanding differences between modelled sea ice simulations based on attributing seasonal ice growth and melt differences. In the method presented, the net downward surface flux is treated as the principal driver of seasonal sea ice growth and melt. An energy balance approach is used to estimate the pointwise effect of model differences in key Arctic climate variables on this surface flux and hence on seasonal sea ice growth and melt. We compare three models with very different historical sea ice simulations: HadGEM2-ES, HadGEM3-GC3.1 and UKESM1.0. The largest driver of differences in ice growth and melt between these models is shown to be the ice area in summer (representing the surface albedo feedback) and the ice thickness distribution in winter (the thickness–growth feedback). Differences in snow and melt pond cover during the early summer exert a smaller effect on the seasonal growth and melt, hence representing the drivers of model differences in both this and in the sea ice volume. In particular, the direct impacts on sea ice growth and melt of differing model parameterisations of snow area and of melt ponds are shown to be small but non-negligible. Text albedo Arctic Sea ice Copernicus Publications: E-Journals Arctic The Cryosphere 16 10 4013 4032 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Arctic sea ice is declining rapidly, but predictions of its future loss are made difficult by the large spread both in present-day and in future sea ice area and volume; hence, there is a need to better understand the drivers of model spread in sea ice state. Here we present a framework for understanding differences between modelled sea ice simulations based on attributing seasonal ice growth and melt differences. In the method presented, the net downward surface flux is treated as the principal driver of seasonal sea ice growth and melt. An energy balance approach is used to estimate the pointwise effect of model differences in key Arctic climate variables on this surface flux and hence on seasonal sea ice growth and melt. We compare three models with very different historical sea ice simulations: HadGEM2-ES, HadGEM3-GC3.1 and UKESM1.0. The largest driver of differences in ice growth and melt between these models is shown to be the ice area in summer (representing the surface albedo feedback) and the ice thickness distribution in winter (the thickness–growth feedback). Differences in snow and melt pond cover during the early summer exert a smaller effect on the seasonal growth and melt, hence representing the drivers of model differences in both this and in the sea ice volume. In particular, the direct impacts on sea ice growth and melt of differing model parameterisations of snow area and of melt ponds are shown to be small but non-negligible. |
format |
Text |
author |
West, Alex Blockley, Edward Collins, Matthew |
spellingShingle |
West, Alex Blockley, Edward Collins, Matthew Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
author_facet |
West, Alex Blockley, Edward Collins, Matthew |
author_sort |
West, Alex |
title |
Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
title_short |
Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
title_full |
Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
title_fullStr |
Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
title_full_unstemmed |
Understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
title_sort |
understanding model spread in sea ice volume by attribution of model differences in seasonal ice growth and melt |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-4013-2022 https://tc.copernicus.org/articles/16/4013/2022/ |
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-16-4013-2022 https://tc.copernicus.org/articles/16/4013/2022/ |
op_doi |
https://doi.org/10.5194/tc-16-4013-2022 |
container_title |
The Cryosphere |
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16 |
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10 |
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4013 |
op_container_end_page |
4032 |
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1766248640428376064 |