Windiness spells in SW Europe since the last glacial maximum
Dunefields have a great potential to unravel past regimes of atmospheric circulation as they record direct traces of this component of the climate system. Along the Portuguese coast, transgressive dunefields represent relict features originated by intense and frequent westerly winds that largely con...
Published in: | Earth and Planetary Science Letters |
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Online Access: | http://hdl.handle.net/10400.1/9623 https://doi.org/10.1016/j.epsl.2015.12.023 |
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ftunivalgarve:oai:sapientia.ualg.pt:10400.1/9623 2023-05-15T17:31:41+02:00 Windiness spells in SW Europe since the last glacial maximum Costas, Susana Naughton, F. Goble, Ronald Renssen, Hans 2016-02 http://hdl.handle.net/10400.1/9623 https://doi.org/10.1016/j.epsl.2015.12.023 eng eng info:eu-repo/grantAgreement/EC/FP7/603458/EU WOS:000369680800009 0012-821X http://hdl.handle.net/10400.1/9623 doi:10.1016/j.epsl.2015.12.023 openAccess article 2016 ftunivalgarve https://doi.org/10.1016/j.epsl.2015.12.023 2022-05-30T08:47:38Z Dunefields have a great potential to unravel past regimes of atmospheric circulation as they record direct traces of this component of the climate system. Along the Portuguese coast, transgressive dunefields represent relict features originated by intense and frequent westerly winds that largely contrast with present conditions, clearly dominated by weaker northwesterly winds. Optical dating and subsurface stratigraphy document three age clusters indicating main episodes of dune mobilization during: the last termination (20-11.6 ka), Middle Holocene (5.6 ka), and Late Holocene (1.2-0.98 and 0.4-0.15 ka).We find reconstructed windfields to be analogous during all episodes and dominated by strong westerlies. Yet, larger grain size diameters and dune volumes documented for the last termination support amplified patterns compatible with a southward shift and intensification of the North Atlantic westerlies during winters. Conversely, dunes deposited after the Middle Holocene are compatible with more variable windfields and weakened patterns controlled by interannual shifts towards low values of the North Atlantic Oscillation (NAO).This work demonstrates that present windfield regimes in southern Europe are not compatible with past aeolian activity. Indeed, present day analogs indicate that wind intensities compatible with past aeolian activity are rare at present (sediment transport potentials below estimates in the aeolian record), but can occur if the jet stream is diverted to the south (i.e. 30 degrees N with negative NAO index) or if very deep cyclones anchor around 50 degrees N, extending their influence to the western Portuguese coast (relatively low NAO index). However, these conditions represent temporary patterns lasting around one day, while we suggest that the identified episodes of aeolian activity may represent semi-permanent conditions. (C) 2016 Elsevier B.V. All rights reserved. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Universidade do Algarve: Sapienta Earth and Planetary Science Letters 436 82 92 |
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Open Polar |
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Universidade do Algarve: Sapienta |
op_collection_id |
ftunivalgarve |
language |
English |
description |
Dunefields have a great potential to unravel past regimes of atmospheric circulation as they record direct traces of this component of the climate system. Along the Portuguese coast, transgressive dunefields represent relict features originated by intense and frequent westerly winds that largely contrast with present conditions, clearly dominated by weaker northwesterly winds. Optical dating and subsurface stratigraphy document three age clusters indicating main episodes of dune mobilization during: the last termination (20-11.6 ka), Middle Holocene (5.6 ka), and Late Holocene (1.2-0.98 and 0.4-0.15 ka).We find reconstructed windfields to be analogous during all episodes and dominated by strong westerlies. Yet, larger grain size diameters and dune volumes documented for the last termination support amplified patterns compatible with a southward shift and intensification of the North Atlantic westerlies during winters. Conversely, dunes deposited after the Middle Holocene are compatible with more variable windfields and weakened patterns controlled by interannual shifts towards low values of the North Atlantic Oscillation (NAO).This work demonstrates that present windfield regimes in southern Europe are not compatible with past aeolian activity. Indeed, present day analogs indicate that wind intensities compatible with past aeolian activity are rare at present (sediment transport potentials below estimates in the aeolian record), but can occur if the jet stream is diverted to the south (i.e. 30 degrees N with negative NAO index) or if very deep cyclones anchor around 50 degrees N, extending their influence to the western Portuguese coast (relatively low NAO index). However, these conditions represent temporary patterns lasting around one day, while we suggest that the identified episodes of aeolian activity may represent semi-permanent conditions. (C) 2016 Elsevier B.V. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Costas, Susana Naughton, F. Goble, Ronald Renssen, Hans |
spellingShingle |
Costas, Susana Naughton, F. Goble, Ronald Renssen, Hans Windiness spells in SW Europe since the last glacial maximum |
author_facet |
Costas, Susana Naughton, F. Goble, Ronald Renssen, Hans |
author_sort |
Costas, Susana |
title |
Windiness spells in SW Europe since the last glacial maximum |
title_short |
Windiness spells in SW Europe since the last glacial maximum |
title_full |
Windiness spells in SW Europe since the last glacial maximum |
title_fullStr |
Windiness spells in SW Europe since the last glacial maximum |
title_full_unstemmed |
Windiness spells in SW Europe since the last glacial maximum |
title_sort |
windiness spells in sw europe since the last glacial maximum |
publishDate |
2016 |
url |
http://hdl.handle.net/10400.1/9623 https://doi.org/10.1016/j.epsl.2015.12.023 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/603458/EU WOS:000369680800009 0012-821X http://hdl.handle.net/10400.1/9623 doi:10.1016/j.epsl.2015.12.023 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.1016/j.epsl.2015.12.023 |
container_title |
Earth and Planetary Science Letters |
container_volume |
436 |
container_start_page |
82 |
op_container_end_page |
92 |
_version_ |
1766129382383943680 |