Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet
peer reviewed Since 2007, there has been a series of surface melt records over the Greenland ice sheet (GrIS), continuing the trend towards increased melt observed since the end of the 1990's. The last two decades are characterized by an increase of negative phases of the North Atlantic Oscilla...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus
2013
|
Subjects: | |
Online Access: | https://orbi.uliege.be/handle/2268/131279 https://orbi.uliege.be/bitstream/2268/131279/1/tc-7-241-2013.pdf https://doi.org/10.5194/tc-7-241-2013 |
id |
ftorbi:oai:orbi.ulg.ac.be:2268/131279 |
---|---|
record_format |
openpolar |
spelling |
ftorbi:oai:orbi.ulg.ac.be:2268/131279 2024-04-21T07:54:34+00:00 Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet Fettweis, Xavier Hanna, Edward Lang, Charlotte Belleflamme, Alexandre Erpicum, Michel Gallée, Hubert 2013-02-07 https://orbi.uliege.be/handle/2268/131279 https://orbi.uliege.be/bitstream/2268/131279/1/tc-7-241-2013.pdf https://doi.org/10.5194/tc-7-241-2013 en eng Copernicus http://www.the-cryosphere.net/7/241/2013/tc-7-241-2013.html urn:issn:1994-0416 urn:issn:1994-0424 https://orbi.uliege.be/handle/2268/131279 info:hdl:2268/131279 https://orbi.uliege.be/bitstream/2268/131279/1/tc-7-241-2013.pdf doi:10.5194/tc-7-241-2013 scopus-id:2-s2.0-84874077692 open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess The Cryosphere, 7, 241–248 (2013-02-07) Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique journal article http://purl.org/coar/resource_type/c_6501 info:eu-repo/semantics/article peer reviewed 2013 ftorbi https://doi.org/10.5194/tc-7-241-2013 2024-03-27T14:58:15Z peer reviewed Since 2007, there has been a series of surface melt records over the Greenland ice sheet (GrIS), continuing the trend towards increased melt observed since the end of the 1990's. The last two decades are characterized by an increase of negative phases of the North Atlantic Oscillation (NAO) favouring warmer and drier summers than normal over GrIS. In this context, we use a circulation type classification based on daily 500 hPa geopotential height to evaluate the role of atmospheric dynamics in this surface melt acceleration for the last two decades. Due to the lack of direct observations, the interannual melt variability is gauged here by the summer (June–July–August) mean temperature from reanalyses at 700 hPa over Greenland; analogous atmospheric circulations in the past show that ~70% of the 1993–2012 warming at 700 hPa over Greenland has been driven by changes in the atmospheric flow frequencies. Indeed, the occurrence of anticyclones centred over the GrIS at the surface and at 500 hPa has doubled since the end of 1990's, which induces more frequent southerly warm air advection along the western Greenland coast and over the neighbouring Canadian Arctic Archipelago (CAA). These changes in the NAO modes explain also why no significant warming has been observed these last summers over Svalbard, where northerly atmospheric flows are twice as frequent as before. Therefore, the recent warmer summers over GrIS and CAA cannot be considered as a long-term climate warming but are more a consequence of NAO variability affecting atmospheric heat transport. Although no global model from the CMIP5 database projects subsequent significant changes in NAO through this century, we cannot exclude the possibility that the observed NAO changes are due to global warming. Article in Journal/Newspaper Arctic Archipelago Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere University of Liège: ORBi (Open Repository and Bibliography) The Cryosphere 7 1 241 248 |
institution |
Open Polar |
collection |
University of Liège: ORBi (Open Repository and Bibliography) |
op_collection_id |
ftorbi |
language |
English |
topic |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique |
spellingShingle |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique Fettweis, Xavier Hanna, Edward Lang, Charlotte Belleflamme, Alexandre Erpicum, Michel Gallée, Hubert Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
topic_facet |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique |
description |
peer reviewed Since 2007, there has been a series of surface melt records over the Greenland ice sheet (GrIS), continuing the trend towards increased melt observed since the end of the 1990's. The last two decades are characterized by an increase of negative phases of the North Atlantic Oscillation (NAO) favouring warmer and drier summers than normal over GrIS. In this context, we use a circulation type classification based on daily 500 hPa geopotential height to evaluate the role of atmospheric dynamics in this surface melt acceleration for the last two decades. Due to the lack of direct observations, the interannual melt variability is gauged here by the summer (June–July–August) mean temperature from reanalyses at 700 hPa over Greenland; analogous atmospheric circulations in the past show that ~70% of the 1993–2012 warming at 700 hPa over Greenland has been driven by changes in the atmospheric flow frequencies. Indeed, the occurrence of anticyclones centred over the GrIS at the surface and at 500 hPa has doubled since the end of 1990's, which induces more frequent southerly warm air advection along the western Greenland coast and over the neighbouring Canadian Arctic Archipelago (CAA). These changes in the NAO modes explain also why no significant warming has been observed these last summers over Svalbard, where northerly atmospheric flows are twice as frequent as before. Therefore, the recent warmer summers over GrIS and CAA cannot be considered as a long-term climate warming but are more a consequence of NAO variability affecting atmospheric heat transport. Although no global model from the CMIP5 database projects subsequent significant changes in NAO through this century, we cannot exclude the possibility that the observed NAO changes are due to global warming. |
format |
Article in Journal/Newspaper |
author |
Fettweis, Xavier Hanna, Edward Lang, Charlotte Belleflamme, Alexandre Erpicum, Michel Gallée, Hubert |
author_facet |
Fettweis, Xavier Hanna, Edward Lang, Charlotte Belleflamme, Alexandre Erpicum, Michel Gallée, Hubert |
author_sort |
Fettweis, Xavier |
title |
Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
title_short |
Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
title_full |
Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
title_fullStr |
Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
title_full_unstemmed |
Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet |
title_sort |
important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the greenland ice sheet |
publisher |
Copernicus |
publishDate |
2013 |
url |
https://orbi.uliege.be/handle/2268/131279 https://orbi.uliege.be/bitstream/2268/131279/1/tc-7-241-2013.pdf https://doi.org/10.5194/tc-7-241-2013 |
genre |
Arctic Archipelago Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere |
genre_facet |
Arctic Archipelago Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere |
op_source |
The Cryosphere, 7, 241–248 (2013-02-07) |
op_relation |
http://www.the-cryosphere.net/7/241/2013/tc-7-241-2013.html urn:issn:1994-0416 urn:issn:1994-0424 https://orbi.uliege.be/handle/2268/131279 info:hdl:2268/131279 https://orbi.uliege.be/bitstream/2268/131279/1/tc-7-241-2013.pdf doi:10.5194/tc-7-241-2013 scopus-id:2-s2.0-84874077692 |
op_rights |
open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-7-241-2013 |
container_title |
The Cryosphere |
container_volume |
7 |
container_issue |
1 |
container_start_page |
241 |
op_container_end_page |
248 |
_version_ |
1796937073176870912 |