| 1. |
- Eldevik, Tor, et al.
(författare)
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Observed sources and variability of Nordic seas overflow
- 2009
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 2, s. 406-410
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Tidskriftsartikel (refereegranskat)abstract
- The overflows from the Nordic seas maintain the deep branch of the North Atlantic Ocean's thermohaline circulation1, 2, an important part of the global climate system3, 4. However, the source of these overflows, and of overflow variability, is debated: proposals include open-ocean convection, dense-water production on the Arctic shelves and the gradual transformation of Atlantic water as it circulates the periphery of the Nordic seas and the Arctic Ocean2, 5, 6. Here we analyse time series of observed ocean temperature and salinity between 1950 and 2005. We find that the progression of thermohaline anomalies on interannual to decadal timescales does not support a systematic response of the overflow properties to convective mixing in the Greenland Sea as has been suggested7, 8. Instead, anomalies in temperature and salinity that leave the northern seas at the Denmark Strait have travelled along the rim of the Nordic seas from inflow to overflow. Furthermore, the Faroe–Shetland Channel reflects the variability of an overturning loop within the Norwegian Sea that has not been observed previously. We thus conclude that the Atlantic water circulating in the Nordic seas is the main source for change in the overflow waters.
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| 2. |
- Ferreira, David, et al.
(författare)
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Atlantic-Pacific Asymmetry in Deep Water Formation
- 2018
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Ingår i: Annual Review of Earth and Planetary Science. - : Annual Reviews. - 0084-6597 .- 1545-4495. ; 46, s. 327-352
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Forskningsöversikt (refereegranskat)abstract
- While the Atlantic Ocean is ventilated by high-latitude deep water formation and exhibits a pole-to-pole overturning circulation, the Pacific Ocean does not. This asymmetric global overturning pattern has persisted for the past 2-3 million years, with evidence for different ventilation modes in the deeper past. In the current climate, the Atlantic-Pacific asymmetry occurs because the Atlantic is more saline, enabling deep convection. To what extent the salinity contrast between the two basins is dominated by atmospheric processes (larger net evaporation over the Atlantic) or oceanic processes (salinity transport into the Atlantic) remains an outstanding question. Numerical simulations have provided support for both mechanisms; observations of the present climate support a strong role for atmospheric processes as well as some modulation by oceanic processes. A major avenue for future work is the quantification of the various processes at play to identify which mechanisms are primary in different climate states.
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| 3. |
- Raj, Roshin P., et al.
(författare)
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The Lofoten Vortex of the Nordic Seas
- 2015
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Ingår i: Deep Sea Research Part I. - : Elsevier BV. - 0967-0637 .- 1879-0119. ; 96, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- The Lofoten Basin is the largest reservoir of ocean heat in the Nordic Seas. A particular feature of the basin is 'the Lofoten Vortex', a most anomalous mesoscale structure in the Nordic Seas. The vortex resides in one of the major winter convection sites in the Norwegian Sea, and is likely to influence the dense water formation of the region. Here, we document this quasi-permanent anticyclonic vortex using hydrographic and satellite observations. The vortex' uniqueness in the Nordic Seas, its surface characteristics on seasonal, inter-annual, and climatological time-scales, are examined together with the main forcing mechanisms acting on it. The influence of the vortex on the hydrography of the Lofoten Basin is also shown. We show that the Atlantic Water in the Nordic Seas penetrate the deepest inside the Lofoten Vortex, and confirm the persistent existence of the vortex in the deepest part of the Lofoten Basin, its dominant cyclonic drift and reveal seasonality in its eddy intensity with maximum during late winter and minimum during late autumn. Eddy merging processes are studied in detail, and mergers by eddies from the slope current are found to provide anticyclonic vorticity to the Lofoten Vortex.
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| 4. |
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