CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates
With the ongoing decline in Arctic sea ice extent, the accurate simulation of Arctic sea ice in coupled models remains an important problem in climate modelling. In this study, the substantial CMIP6 model spread in Arctic sea ice extent and volume is investigated using a novel, process-based approac...
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ftcopernicus:oai:publications.copernicus.org:gmdd121529 2024-09-15T17:58:48+00:00 CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates West, Alex Edward Blockley, Edward William 2024-08-26 application/pdf https://doi.org/10.5194/gmd-2024-121 https://gmd.copernicus.org/preprints/gmd-2024-121/ eng eng doi:10.5194/gmd-2024-121 https://gmd.copernicus.org/preprints/gmd-2024-121/ eISSN: 1991-9603 Text 2024 ftcopernicus https://doi.org/10.5194/gmd-2024-121 2024-08-28T05:24:22Z With the ongoing decline in Arctic sea ice extent, the accurate simulation of Arctic sea ice in coupled models remains an important problem in climate modelling. In this study, the substantial CMIP6 model spread in Arctic sea ice extent and volume is investigated using a novel, process-based approach. An observational dataset derived from the Arctic Ice Mass Balance buoy (IMB) network is used to evaluate the thermodynamic and mass balance diagnostics produced by a subset of CMIP6 models, to better understand the model processes that underlie the large-scale sea ice states. Due to the sparse nature of the IMB observations, the evaluation is performed by comparing distributions of modelled and observed fluxes in the densely sampled regions of the North Pole and Beaufort Sea. We find that all fluxes are routinely biased high in magnitude with respect to the IMB measurements by nearly all models, with too much melt in summer, and too much conduction and growth in winter, even as a function of ice thickness. We also show that choices of thermodynamic parameterisation substantially influence particular fluxes in physically realistic ways, and that these effects likely modulate the large-scale relationship between ice thickness and ice growth and melt in the CMIP6 models. Text Beaufort Sea North Pole Sea ice Copernicus Publications: E-Journals |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
With the ongoing decline in Arctic sea ice extent, the accurate simulation of Arctic sea ice in coupled models remains an important problem in climate modelling. In this study, the substantial CMIP6 model spread in Arctic sea ice extent and volume is investigated using a novel, process-based approach. An observational dataset derived from the Arctic Ice Mass Balance buoy (IMB) network is used to evaluate the thermodynamic and mass balance diagnostics produced by a subset of CMIP6 models, to better understand the model processes that underlie the large-scale sea ice states. Due to the sparse nature of the IMB observations, the evaluation is performed by comparing distributions of modelled and observed fluxes in the densely sampled regions of the North Pole and Beaufort Sea. We find that all fluxes are routinely biased high in magnitude with respect to the IMB measurements by nearly all models, with too much melt in summer, and too much conduction and growth in winter, even as a function of ice thickness. We also show that choices of thermodynamic parameterisation substantially influence particular fluxes in physically realistic ways, and that these effects likely modulate the large-scale relationship between ice thickness and ice growth and melt in the CMIP6 models. |
format |
Text |
author |
West, Alex Edward Blockley, Edward William |
spellingShingle |
West, Alex Edward Blockley, Edward William CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
author_facet |
West, Alex Edward Blockley, Edward William |
author_sort |
West, Alex Edward |
title |
CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
title_short |
CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
title_full |
CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
title_fullStr |
CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
title_full_unstemmed |
CMIP6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
title_sort |
cmip6 models overestimate sea ice melt, growth & conduction relative to ice mass balance buoy estimates |
publishDate |
2024 |
url |
https://doi.org/10.5194/gmd-2024-121 https://gmd.copernicus.org/preprints/gmd-2024-121/ |
genre |
Beaufort Sea North Pole Sea ice |
genre_facet |
Beaufort Sea North Pole Sea ice |
op_source |
eISSN: 1991-9603 |
op_relation |
doi:10.5194/gmd-2024-121 https://gmd.copernicus.org/preprints/gmd-2024-121/ |
op_doi |
https://doi.org/10.5194/gmd-2024-121 |
_version_ |
1810435772854042624 |