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| Titel |
Increasing presence of Arctic Ocean deep waters in the Greenland Sea |
| VerfasserIn |
Raquel Somavilla Cabrillo, Ursula Schauer, Gedeon Budeus |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081923
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| Zusammenfassung |
| Deep convection has been known to provide the coldest and freshest waters to the deep
Greenland Sea, whose properties are balanced with the advection of warmer and saltier
waters from the deep Arctic Ocean. However, during the last three decades, deep convection
has come to a halt in the Greenland Sea.
As previously reported and updated in this work through the analysis of the free available
hydrographic data in the central Greenland Sea and in the Arctic Ocean from 1950 to 2010
(Pangaea and ICES data bases), as a consequence of this, two major hydrographic changes
are observed: (1) the appearance and deepening of an intermediate temperature maximum and
(2) a continuous warming and saltening of the deep Greenland Sea. The origin of both
findings is found in the advection of Arctic Ocean deep waters from the Amerasian and
Eurasian basins, respectively, into the central Greenland Sea. Associated to the
first, a temperature increase of 0.35Ë C from 1993 to 2009 is observed at 1700
m. Below 2000 m, the temperature and salinity have increased at a mean rate of
0.136Ë C/decade and 0.01decade-1 in the last three decades. Overall, the stop of
deep convection and the advection of Arctic Ocean deep waters result among the
highest deep warming and saltening trends of the World Ocean in the Greenland
Sea.
In addition to the described update of the state of these changes, two new
accomplishments are fulfilled in this study. First, in absence of deep convection, the
continuous changing of the thermohaline properties of the deep Greenland Sea requires
exchanges with adjacent ocean basins. This scenario enables us the estimation of
the necessary transports from the deep Arctic to explain the observed changes. A
transport of Eurasian Basin Deep Water of 0.31±0.04 Sv is obtained. Secondly, the
warming and saltening of the deep Greenland Sea contributes, as any other ocean
basin, to the World Ocean heat content and sea level rise. The estimation of these
contributions shows larger numbers than traditionally expected for Polar Regions:
1% for its contribution to the World Ocean heat content -100 times larger than the
contribution per unit area of the deep Pacific Ocean-; and 0.12% for the global sea level
rise.
The results presented here are relevant not only for future assessments of the state of the
Greenland Sea but also for the entire Arctic Mediterranean, and global energy budget studies. |
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