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| Titel |
Wind forcing of salinity anomalies in the Denmark Strait overflow |
| VerfasserIn |
S. Hall, S. R. Dye, K. J. Heywood, M. R. Wadley |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 7, no. 6 ; Nr. 7, no. 6 (2011-11-30), S.821-834 |
| Datensatznummer |
250004873
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| Publikation (Nr.) |
 copernicus.org/os-7-821-2011.pdf |
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| Zusammenfassung |
| 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. |
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