Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends
Recent work suggests that natural variability has played a significant role in the increase of Antarctic sea ice extent during 1979-2013. The ice extent has responded strongly to atmospheric circulation changes, including a deepened Amundsen Sea Low (ASL), which in part has been driven by tropical v...
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Online Access: | https://doi.org/10.1007/s00382-017-3893-5 |
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ftncar:oai:drupal-site.org:articles_21688 2023-09-05T13:11:46+02:00 Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends Schneider, David P. (author) Deser, Clara (author) 2018-06-01 https://doi.org/10.1007/s00382-017-3893-5 en eng Climate Dynamics--Clim Dyn--0930-7575--1432-0894 articles:21688 ark:/85065/d7vd7266 doi:10.1007/s00382-017-3893-5 Copyright 2018 Springer-Verlag GmbH Germany. article Text 2018 ftncar https://doi.org/10.1007/s00382-017-3893-5 2023-08-14T18:47:44Z Recent work suggests that natural variability has played a significant role in the increase of Antarctic sea ice extent during 1979-2013. The ice extent has responded strongly to atmospheric circulation changes, including a deepened Amundsen Sea Low (ASL), which in part has been driven by tropical variability. Nonetheless, this increase has occurred in the context of externally forced climate change, and it has been difficult to reconcile observed and modeled Antarctic sea ice trends. To understand observed-model disparities, this work defines the internally driven and radiatively forced patterns of Antarctic sea ice change and exposes potential model biases using results from two sets of historical experiments of a coupled climate model compared with observations. One ensemble is constrained only by external factors such as greenhouse gases and stratospheric ozone, while the other explicitly accounts for the influence of tropical variability by specifying observed SST anomalies in the eastern tropical Pacific. The latter experiment reproduces the deepening of the ASL, which drives an increase in regional ice extent due to enhanced ice motion and sea surface cooling. However, the overall sea ice trend in every ensemble member of both experiments is characterized by ice loss and is dominated by the forced pattern, as given by the ensemble-mean of the first experiment. This pervasive ice loss is associated with a strong warming of the ocean mixed layer, suggesting that the ocean model does not locally store or export anomalous heat efficiently enough to maintain a surface environment conducive to sea ice expansion. The pervasive upper-ocean warming, not seen in observations, likely reflects ocean mean-state biases. ANT1235231 Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Sea ice OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Amundsen Sea Antarctic Pacific Climate Dynamics 50 11-12 4599 4618 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
Recent work suggests that natural variability has played a significant role in the increase of Antarctic sea ice extent during 1979-2013. The ice extent has responded strongly to atmospheric circulation changes, including a deepened Amundsen Sea Low (ASL), which in part has been driven by tropical variability. Nonetheless, this increase has occurred in the context of externally forced climate change, and it has been difficult to reconcile observed and modeled Antarctic sea ice trends. To understand observed-model disparities, this work defines the internally driven and radiatively forced patterns of Antarctic sea ice change and exposes potential model biases using results from two sets of historical experiments of a coupled climate model compared with observations. One ensemble is constrained only by external factors such as greenhouse gases and stratospheric ozone, while the other explicitly accounts for the influence of tropical variability by specifying observed SST anomalies in the eastern tropical Pacific. The latter experiment reproduces the deepening of the ASL, which drives an increase in regional ice extent due to enhanced ice motion and sea surface cooling. However, the overall sea ice trend in every ensemble member of both experiments is characterized by ice loss and is dominated by the forced pattern, as given by the ensemble-mean of the first experiment. This pervasive ice loss is associated with a strong warming of the ocean mixed layer, suggesting that the ocean model does not locally store or export anomalous heat efficiently enough to maintain a surface environment conducive to sea ice expansion. The pervasive upper-ocean warming, not seen in observations, likely reflects ocean mean-state biases. ANT1235231 |
author2 |
Schneider, David P. (author) Deser, Clara (author) |
format |
Article in Journal/Newspaper |
title |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
spellingShingle |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
title_short |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
title_full |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
title_fullStr |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
title_full_unstemmed |
Tropically driven and externally forced patterns of Antarctic sea ice change: Reconciling observed and modeled trends |
title_sort |
tropically driven and externally forced patterns of antarctic sea ice change: reconciling observed and modeled trends |
publishDate |
2018 |
url |
https://doi.org/10.1007/s00382-017-3893-5 |
geographic |
Amundsen Sea Antarctic Pacific |
geographic_facet |
Amundsen Sea Antarctic Pacific |
genre |
Amundsen Sea Antarc* Antarctic Sea ice |
genre_facet |
Amundsen Sea Antarc* Antarctic Sea ice |
op_relation |
Climate Dynamics--Clim Dyn--0930-7575--1432-0894 articles:21688 ark:/85065/d7vd7266 doi:10.1007/s00382-017-3893-5 |
op_rights |
Copyright 2018 Springer-Verlag GmbH Germany. |
op_doi |
https://doi.org/10.1007/s00382-017-3893-5 |
container_title |
Climate Dynamics |
container_volume |
50 |
container_issue |
11-12 |
container_start_page |
4599 |
op_container_end_page |
4618 |
_version_ |
1776196998854082560 |