On the limited ice intrusion in Alaska at the LGM
The Last Glacial Maximum (LGM) Laurentide Ice Sheet covered most of the North American continent poleward of 40 degrees N, with the exception of Alaska that remained relatively warm, dry, and largely ice free. Experiments with a global atmospheric circulation model are in broad agreement with proxie...
Published in: | Geophysical Research Letters |
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Language: | English |
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2016
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Online Access: | https://doi.org/10.1002/2016GL071012 |
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ftncar:oai:drupal-site.org:articles_19318 2023-09-05T13:20:15+02:00 On the limited ice intrusion in Alaska at the LGM Löfverström, Marcus (author) Liakka, Johan (author) 2016-10-28 https://doi.org/10.1002/2016GL071012 en eng Geophysical Research Letters--Geophys. Res. Lett.--00948276 articles:19318 ark:/85065/d72j6dmk doi:10.1002/2016GL071012 Copyright 2016 American Geophysical Union. article Text 2016 ftncar https://doi.org/10.1002/2016GL071012 2023-08-14T18:45:41Z The Last Glacial Maximum (LGM) Laurentide Ice Sheet covered most of the North American continent poleward of 40 degrees N, with the exception of Alaska that remained relatively warm, dry, and largely ice free. Experiments with a global atmospheric circulation model are in broad agreement with proxies: the Alaskan summer temperatures are comparable to the preindustrial, and the annual precipitation is reduced by 30-50%. The warm conditions are attributed to a lowering of the local planetary albedodue to a decreased cloudiness in response to the cold LGM sea surface temperatures (SSTs) and a stationary anticyclone forced by the ice sheetthat allows more shortwave radiation to reach the surface. Stationary waves are shown to counteract the shortwave cloud feedback by converging less heat over the target region. The LGM SST field also yields an equatorward shifted Pacific stormtrack, which results in drier conditions in Alaska and abundant precipitation at the southern margin of the Laurentide Ice Sheet. Article in Journal/Newspaper Ice Sheet Alaska OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Pacific Geophysical Research Letters 43 20 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
The Last Glacial Maximum (LGM) Laurentide Ice Sheet covered most of the North American continent poleward of 40 degrees N, with the exception of Alaska that remained relatively warm, dry, and largely ice free. Experiments with a global atmospheric circulation model are in broad agreement with proxies: the Alaskan summer temperatures are comparable to the preindustrial, and the annual precipitation is reduced by 30-50%. The warm conditions are attributed to a lowering of the local planetary albedodue to a decreased cloudiness in response to the cold LGM sea surface temperatures (SSTs) and a stationary anticyclone forced by the ice sheetthat allows more shortwave radiation to reach the surface. Stationary waves are shown to counteract the shortwave cloud feedback by converging less heat over the target region. The LGM SST field also yields an equatorward shifted Pacific stormtrack, which results in drier conditions in Alaska and abundant precipitation at the southern margin of the Laurentide Ice Sheet. |
author2 |
Löfverström, Marcus (author) Liakka, Johan (author) |
format |
Article in Journal/Newspaper |
title |
On the limited ice intrusion in Alaska at the LGM |
spellingShingle |
On the limited ice intrusion in Alaska at the LGM |
title_short |
On the limited ice intrusion in Alaska at the LGM |
title_full |
On the limited ice intrusion in Alaska at the LGM |
title_fullStr |
On the limited ice intrusion in Alaska at the LGM |
title_full_unstemmed |
On the limited ice intrusion in Alaska at the LGM |
title_sort |
on the limited ice intrusion in alaska at the lgm |
publishDate |
2016 |
url |
https://doi.org/10.1002/2016GL071012 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Ice Sheet Alaska |
genre_facet |
Ice Sheet Alaska |
op_relation |
Geophysical Research Letters--Geophys. Res. Lett.--00948276 articles:19318 ark:/85065/d72j6dmk doi:10.1002/2016GL071012 |
op_rights |
Copyright 2016 American Geophysical Union. |
op_doi |
https://doi.org/10.1002/2016GL071012 |
container_title |
Geophysical Research Letters |
container_volume |
43 |
container_issue |
20 |
_version_ |
1776200967345143808 |