Dynamical drivers of Greenland blocking in climate models
Blocking over Greenland is known to lead to strong surface impacts, such as ice sheet melting, and a change in its future frequency can have important consequences. However, as previous studies demonstrated, climate models underestimate the blocking frequency for the historical period. Even though s...
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ftunivbergen:oai:bora.uib.no:11250/2984048 2023-05-15T16:23:27+02:00 Dynamical drivers of Greenland blocking in climate models Michel, Clio Madonna, Erica Spensberger, Clemens Li, Camille Outten, Stephen 2021 application/pdf https://hdl.handle.net/11250/2984048 https://doi.org/10.5194/wcd-2-1131-2021 eng eng Copernicus Publications Notur/NorStore: NS9770K https://hdl.handle.net/11250/2984048 https://doi.org/10.5194/wcd-2-1131-2021 cristin:1966320 Weather and Climate Dynamics. 2021, 2 (4), 1131-1148. Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright Author(s) 2021 Weather and Climate Dynamics (WCD) 1131-1148 2 4 Journal article Peer reviewed 2021 ftunivbergen https://doi.org/10.5194/wcd-2-1131-2021 2023-03-14T17:45:02Z Blocking over Greenland is known to lead to strong surface impacts, such as ice sheet melting, and a change in its future frequency can have important consequences. However, as previous studies demonstrated, climate models underestimate the blocking frequency for the historical period. Even though some improvements have recently been made, the reasons for the model biases are still unclear. This study investigates whether models with realistic Greenland blocking frequency in winter have a correct representation of its dynamical drivers, most importantly, cyclonic wave breaking (CWB). Because blocking is a rare event and its representation is model-dependent, we use a multi-model large ensemble. We focus on two models that show typical Greenland blocking features, namely a ridge over Greenland and an equatorward-shifted jet over the North Atlantic. ECHAM6.3-LR has the best representation of CWB of the models investigated but only the second best representation of Greenland blocking frequency, which is underestimated by a factor of 2. While MIROC5 has the most realistic Greenland blocking frequency, it also has the largest (negative) CWB frequency bias, suggesting that another mechanism leads to blocking in this model. Composites over Greenland blocking days show that the present and future experiments of each model are very similar to each other in both amplitude and pattern and that there is no significant change in Greenland blocking frequency in the future. However, these projected changes in blocking frequency are highly uncertain as long as the mechanisms leading to blocking formation and maintenance in models remain poorly understood. publishedVersion Article in Journal/Newspaper Greenland Ice Sheet North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Greenland Weather and Climate Dynamics 2 4 1131 1148 |
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Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
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ftunivbergen |
language |
English |
description |
Blocking over Greenland is known to lead to strong surface impacts, such as ice sheet melting, and a change in its future frequency can have important consequences. However, as previous studies demonstrated, climate models underestimate the blocking frequency for the historical period. Even though some improvements have recently been made, the reasons for the model biases are still unclear. This study investigates whether models with realistic Greenland blocking frequency in winter have a correct representation of its dynamical drivers, most importantly, cyclonic wave breaking (CWB). Because blocking is a rare event and its representation is model-dependent, we use a multi-model large ensemble. We focus on two models that show typical Greenland blocking features, namely a ridge over Greenland and an equatorward-shifted jet over the North Atlantic. ECHAM6.3-LR has the best representation of CWB of the models investigated but only the second best representation of Greenland blocking frequency, which is underestimated by a factor of 2. While MIROC5 has the most realistic Greenland blocking frequency, it also has the largest (negative) CWB frequency bias, suggesting that another mechanism leads to blocking in this model. Composites over Greenland blocking days show that the present and future experiments of each model are very similar to each other in both amplitude and pattern and that there is no significant change in Greenland blocking frequency in the future. However, these projected changes in blocking frequency are highly uncertain as long as the mechanisms leading to blocking formation and maintenance in models remain poorly understood. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Michel, Clio Madonna, Erica Spensberger, Clemens Li, Camille Outten, Stephen |
spellingShingle |
Michel, Clio Madonna, Erica Spensberger, Clemens Li, Camille Outten, Stephen Dynamical drivers of Greenland blocking in climate models |
author_facet |
Michel, Clio Madonna, Erica Spensberger, Clemens Li, Camille Outten, Stephen |
author_sort |
Michel, Clio |
title |
Dynamical drivers of Greenland blocking in climate models |
title_short |
Dynamical drivers of Greenland blocking in climate models |
title_full |
Dynamical drivers of Greenland blocking in climate models |
title_fullStr |
Dynamical drivers of Greenland blocking in climate models |
title_full_unstemmed |
Dynamical drivers of Greenland blocking in climate models |
title_sort |
dynamical drivers of greenland blocking in climate models |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2984048 https://doi.org/10.5194/wcd-2-1131-2021 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet North Atlantic |
genre_facet |
Greenland Ice Sheet North Atlantic |
op_source |
Weather and Climate Dynamics (WCD) 1131-1148 2 4 |
op_relation |
Notur/NorStore: NS9770K https://hdl.handle.net/11250/2984048 https://doi.org/10.5194/wcd-2-1131-2021 cristin:1966320 Weather and Climate Dynamics. 2021, 2 (4), 1131-1148. |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright Author(s) 2021 |
op_doi |
https://doi.org/10.5194/wcd-2-1131-2021 |
container_title |
Weather and Climate Dynamics |
container_volume |
2 |
container_issue |
4 |
container_start_page |
1131 |
op_container_end_page |
1148 |
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1766011709507502080 |