Wind forcing of salinity anomalies in the Denmark Strait overflow
The overflow of dense water from the Nordic Seas to the North Atlantic through Denmark Strait is an important part of the global thermohaline circulation. The salinity of the overflow plume has been measured by an array of current meters across the continental slope off the coast of Angmagssalik, so...
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ftdoajarticles:oai:doaj.org/article:ae17a86c44874951975fe4e7ceecefb9 2023-05-15T13:25:48+02:00 Wind forcing of salinity anomalies in the Denmark Strait overflow S. Hall S. R. Dye K. J. Heywood M. R. Wadley 2011-11-01T00:00:00Z https://doi.org/10.5194/os-7-821-2011 https://doaj.org/article/ae17a86c44874951975fe4e7ceecefb9 EN eng Copernicus Publications http://www.ocean-sci.net/7/821/2011/os-7-821-2011.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-7-821-2011 1812-0784 1812-0792 https://doaj.org/article/ae17a86c44874951975fe4e7ceecefb9 Ocean Science, Vol 7, Iss 6, Pp 821-834 (2011) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2011 ftdoajarticles https://doi.org/10.5194/os-7-821-2011 2022-12-30T21:59:46Z The overflow of dense water from the Nordic Seas to the North Atlantic through Denmark Strait is an important part of the global thermohaline circulation. The salinity of the overflow plume has been measured by an array of current meters across the continental slope off the coast of Angmagssalik, southeast Greenland since September 1998. During 2004 the salinity of the overflow plume changed dramatically; the entire width of the array (70 km) freshened between January 2004 and July 2004, with a significant negative salinity anomaly of about 0.06 in May. The event in May represents a fresh anomaly of over 3 standard deviations from the mean since recording began in 1998. The OCCAM 1/12° Ocean General Circulation Model not only reproduces the 2004 freshening event ( r =0.96, p <0.01), but also correlates well with salinity observations over a previous 6 year period ( r =0.54, p <0.01), despite the inevitable limitations of a z-coordinate model in representing the mixing processes at and downstream of the Denmark Strait sill. Consequently the physical processes causing the 2004 anomaly and prior variability in salinity are investigated using the model output. Our results reject the hypotheses that the anomaly is caused by processes occurring between the overflow sill and the moorings, or by an increase in upstream net freshwater input. Instead, we show that the 2004 salinity anomaly is caused by an increase in volume flux of low salinity water, with a potential density greater than 27.60 kg m −3 , flowing towards the Denmark Strait sill in the East Greenland Current. This is caused by an increase in southward wind stress upstream of the sill at around 75° N 20° W four and a half months earlier, and an associated strengthening of the East Greenland Current. Article in Journal/Newspaper Angmagssalik Denmark Strait East Greenland east greenland current Greenland Nordic Seas North Atlantic Directory of Open Access Journals: DOAJ Articles Greenland Ocean Science 7 6 821 834 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 S. Hall S. R. Dye K. J. Heywood M. R. Wadley Wind forcing of salinity anomalies in the Denmark Strait overflow |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
The overflow of dense water from the Nordic Seas to the North Atlantic through Denmark Strait is an important part of the global thermohaline circulation. The salinity of the overflow plume has been measured by an array of current meters across the continental slope off the coast of Angmagssalik, southeast Greenland since September 1998. During 2004 the salinity of the overflow plume changed dramatically; the entire width of the array (70 km) freshened between January 2004 and July 2004, with a significant negative salinity anomaly of about 0.06 in May. The event in May represents a fresh anomaly of over 3 standard deviations from the mean since recording began in 1998. The OCCAM 1/12° Ocean General Circulation Model not only reproduces the 2004 freshening event ( r =0.96, p <0.01), but also correlates well with salinity observations over a previous 6 year period ( r =0.54, p <0.01), despite the inevitable limitations of a z-coordinate model in representing the mixing processes at and downstream of the Denmark Strait sill. Consequently the physical processes causing the 2004 anomaly and prior variability in salinity are investigated using the model output. Our results reject the hypotheses that the anomaly is caused by processes occurring between the overflow sill and the moorings, or by an increase in upstream net freshwater input. Instead, we show that the 2004 salinity anomaly is caused by an increase in volume flux of low salinity water, with a potential density greater than 27.60 kg m −3 , flowing towards the Denmark Strait sill in the East Greenland Current. This is caused by an increase in southward wind stress upstream of the sill at around 75° N 20° W four and a half months earlier, and an associated strengthening of the East Greenland Current. |
format |
Article in Journal/Newspaper |
author |
S. Hall S. R. Dye K. J. Heywood M. R. Wadley |
author_facet |
S. Hall S. R. Dye K. J. Heywood M. R. Wadley |
author_sort |
S. Hall |
title |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
title_short |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
title_full |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
title_fullStr |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
title_full_unstemmed |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
title_sort |
wind forcing of salinity anomalies in the denmark strait overflow |
publisher |
Copernicus Publications |
publishDate |
2011 |
url |
https://doi.org/10.5194/os-7-821-2011 https://doaj.org/article/ae17a86c44874951975fe4e7ceecefb9 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Angmagssalik Denmark Strait East Greenland east greenland current Greenland Nordic Seas North Atlantic |
genre_facet |
Angmagssalik Denmark Strait East Greenland east greenland current Greenland Nordic Seas North Atlantic |
op_source |
Ocean Science, Vol 7, Iss 6, Pp 821-834 (2011) |
op_relation |
http://www.ocean-sci.net/7/821/2011/os-7-821-2011.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-7-821-2011 1812-0784 1812-0792 https://doaj.org/article/ae17a86c44874951975fe4e7ceecefb9 |
op_doi |
https://doi.org/10.5194/os-7-821-2011 |
container_title |
Ocean Science |
container_volume |
7 |
container_issue |
6 |
container_start_page |
821 |
op_container_end_page |
834 |
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1766388378818838528 |