Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations
The indirect effect of winter Arctic Oscillation (AO) events on the following summer Arctic sea ice extent suggests an inherent winter-to-summer mechanism for sea ice predictability. On the other hand, operational regional summer sea ice forecasts in a large number of coupled climate models show a c...
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ftdoajarticles:oai:doaj.org/article:502283b95a45453493fd13877da12090 2023-05-15T14:50:06+02:00 Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations W. Gregory J. Stroeve M. Tsamados 2022-05-01T00:00:00Z https://doi.org/10.5194/tc-16-1653-2022 https://doaj.org/article/502283b95a45453493fd13877da12090 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/1653/2022/tc-16-1653-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-1653-2022 1994-0416 1994-0424 https://doaj.org/article/502283b95a45453493fd13877da12090 The Cryosphere, Vol 16, Pp 1653-1673 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-1653-2022 2022-12-31T02:25:30Z The indirect effect of winter Arctic Oscillation (AO) events on the following summer Arctic sea ice extent suggests an inherent winter-to-summer mechanism for sea ice predictability. On the other hand, operational regional summer sea ice forecasts in a large number of coupled climate models show a considerable drop in predictive skill for forecasts initialised prior to the date of melt onset in spring, suggesting that some drivers of sea ice variability on longer timescales may not be well represented in these models. To this end, we introduce an unsupervised learning approach based on cluster analysis and complex networks to establish how well the latest generation of coupled climate models participating in phase 6 of the World Climate Research Programme Coupled Model Intercomparison Project (CMIP6) are able to reflect the spatio-temporal patterns of variability in Northern Hemisphere winter sea-level pressure and Arctic summer sea ice concentration over the period 1979–2020, relative to ERA5 atmospheric reanalysis and satellite-derived sea ice observations, respectively. Two specific global metrics are introduced as ways to compare patterns of variability between models and observations/reanalysis: the adjusted Rand index – a method for comparing spatial patterns of variability – and a network distance metric – a method for comparing the degree of connectivity between two geographic regions. We find that CMIP6 models generally reflect the spatial pattern of variability in the AO relatively well, although they overestimate the magnitude of sea-level pressure variability over the north-western Pacific Ocean and underestimate the variability over northern Africa and southern Europe. They also underestimate the importance of regions such as the Beaufort, East Siberian, and Laptev seas in explaining pan-Arctic summer sea ice area variability, which we hypothesise is due to regional biases in sea ice thickness. Finally, observations show that historically, winter AO events (negatively) covary strongly with summer ... Article in Journal/Newspaper Arctic laptev Sea ice The Cryosphere Directory of Open Access Journals: DOAJ Articles Arctic Pacific The Cryosphere 16 5 1653 1673 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 W. Gregory J. Stroeve M. Tsamados Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
The indirect effect of winter Arctic Oscillation (AO) events on the following summer Arctic sea ice extent suggests an inherent winter-to-summer mechanism for sea ice predictability. On the other hand, operational regional summer sea ice forecasts in a large number of coupled climate models show a considerable drop in predictive skill for forecasts initialised prior to the date of melt onset in spring, suggesting that some drivers of sea ice variability on longer timescales may not be well represented in these models. To this end, we introduce an unsupervised learning approach based on cluster analysis and complex networks to establish how well the latest generation of coupled climate models participating in phase 6 of the World Climate Research Programme Coupled Model Intercomparison Project (CMIP6) are able to reflect the spatio-temporal patterns of variability in Northern Hemisphere winter sea-level pressure and Arctic summer sea ice concentration over the period 1979–2020, relative to ERA5 atmospheric reanalysis and satellite-derived sea ice observations, respectively. Two specific global metrics are introduced as ways to compare patterns of variability between models and observations/reanalysis: the adjusted Rand index – a method for comparing spatial patterns of variability – and a network distance metric – a method for comparing the degree of connectivity between two geographic regions. We find that CMIP6 models generally reflect the spatial pattern of variability in the AO relatively well, although they overestimate the magnitude of sea-level pressure variability over the north-western Pacific Ocean and underestimate the variability over northern Africa and southern Europe. They also underestimate the importance of regions such as the Beaufort, East Siberian, and Laptev seas in explaining pan-Arctic summer sea ice area variability, which we hypothesise is due to regional biases in sea ice thickness. Finally, observations show that historically, winter AO events (negatively) covary strongly with summer ... |
format |
Article in Journal/Newspaper |
author |
W. Gregory J. Stroeve M. Tsamados |
author_facet |
W. Gregory J. Stroeve M. Tsamados |
author_sort |
W. Gregory |
title |
Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
title_short |
Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
title_full |
Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
title_fullStr |
Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
title_full_unstemmed |
Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations |
title_sort |
network connectivity between the winter arctic oscillation and summer sea ice in cmip6 models and observations |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-1653-2022 https://doaj.org/article/502283b95a45453493fd13877da12090 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic laptev Sea ice The Cryosphere |
genre_facet |
Arctic laptev Sea ice The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 1653-1673 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/1653/2022/tc-16-1653-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-1653-2022 1994-0416 1994-0424 https://doaj.org/article/502283b95a45453493fd13877da12090 |
op_doi |
https://doi.org/10.5194/tc-16-1653-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
5 |
container_start_page |
1653 |
op_container_end_page |
1673 |
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1766321171708510208 |