Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet"
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) fav...
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Online Access: | https://doi.org/10.5194/tc-7-241-2013 https://doaj.org/article/c71e2a5ebc8c4778b132b274b65c105f |
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ftdoajarticles:oai:doaj.org/article:c71e2a5ebc8c4778b132b274b65c105f 2023-05-15T14:28:59+02:00 Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" H. Gallée M. Erpicum A. Belleflamme C. Lang E. Hanna X. Fettweis 2013-02-01T00:00:00Z https://doi.org/10.5194/tc-7-241-2013 https://doaj.org/article/c71e2a5ebc8c4778b132b274b65c105f EN eng Copernicus Publications http://www.the-cryosphere.net/7/241/2013/tc-7-241-2013.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-7-241-2013 1994-0416 1994-0424 https://doaj.org/article/c71e2a5ebc8c4778b132b274b65c105f The Cryosphere, Vol 7, Iss 1, Pp 241-248 (2013) Environmental sciences GE1-350 Geology QE1-996.5 article 2013 ftdoajarticles https://doi.org/10.5194/tc-7-241-2013 2022-12-31T10:59:23Z 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 Arctic Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere Directory of Open Access Journals: DOAJ Articles Arctic Canadian Arctic Archipelago Greenland Svalbard The Cryosphere 7 1 241 248 |
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 H. Gallée M. Erpicum A. Belleflamme C. Lang E. Hanna X. Fettweis Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
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 |
H. Gallée M. Erpicum A. Belleflamme C. Lang E. Hanna X. Fettweis |
author_facet |
H. Gallée M. Erpicum A. Belleflamme C. Lang E. Hanna X. Fettweis |
author_sort |
H. Gallée |
title |
Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
title_short |
Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
title_full |
Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
title_fullStr |
Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
title_full_unstemmed |
Brief communication "Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet" |
title_sort |
brief communication "important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the greenland ice sheet" |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/tc-7-241-2013 https://doaj.org/article/c71e2a5ebc8c4778b132b274b65c105f |
geographic |
Arctic Canadian Arctic Archipelago Greenland Svalbard |
geographic_facet |
Arctic Canadian Arctic Archipelago Greenland Svalbard |
genre |
Arctic Archipelago Arctic Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere |
genre_facet |
Arctic Archipelago Arctic Canadian Arctic Archipelago Global warming Greenland Ice Sheet North Atlantic North Atlantic oscillation Svalbard The Cryosphere |
op_source |
The Cryosphere, Vol 7, Iss 1, Pp 241-248 (2013) |
op_relation |
http://www.the-cryosphere.net/7/241/2013/tc-7-241-2013.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-7-241-2013 1994-0416 1994-0424 https://doaj.org/article/c71e2a5ebc8c4778b132b274b65c105f |
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_ |
1766303089847959552 |