scholarly journals The deepening of the Atlantic water in the Lofoten Basin of the Norwegian Sea, demonstrated by using an active reduced gravity model

2004 ◽  
Vol 31 (1) ◽  
Author(s):  
Kjell Arild Orvik
Keyword(s):  
Gravity Model ◽  
Atlantic Water ◽  
Reduced Gravity ◽  
Norwegian Sea

Do Greenland Ice Cores Reflect NW European Interglacial Climate Variations?

1995 ◽  
Vol 43 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Eiliv Larsen ◽  
Hans Petter Sejrup ◽  
Sigfus J. Johnsen ◽  
Karen Luise Knudsen
Keyword(s):  
Western Europe ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
High Amplitude ◽  
Atlantic Water ◽  
Polar Front ◽  
Norwegian Sea ◽  
The Holocene ◽  
Climatic Evolution

AbstractThe climatic evolution during the Eemian and the Holocene in western Europe is compared with the sea-surface conditions in the Norwegian Sea and with the oxygen-isotope-derived paleotemperature signal in the GRIP and Renland ice cores from Greenland. The records show a warm phase (ca. 3000 yr long) early in the Eemian (substage 5e). This suggests that the Greenland ice sheet, in general, recorded the climate in the region during this time. Rapid fluctuations during late stage 6 and late substage 5e in the GRIP ice core apparently are not recorded in the climatic proxies from western Europe and the Norwegian Sea. This may be due to low resolution in the terrestrial and marine records and/or long response time of the biotic changes. The early Holocene climatic optimum recorded in the terrestrial and marine records in the Norwegian Sea-NW European region is not found in the Summit (GRIP and GISP2) ice cores. However, this warm phase is recorded in the Renland ice core. Due to the proximity of Renland to the Norwegian Sea, this area is probably more influenced by changes in polar front positions which may partly explain this discrepancy. A reduction in the elevation at Summit during the Holocene may, however, be just as important. The high-amplitude shifts during substage 5e in the GRIP core could be due to Atlantic water oscillating closer to, and also reaching, the coast of East Greenland. During the Holocene, Atlantic water was generally located farther east in the Norwegian Sea than during the Eemian.

A reduced-gravity model of the Catalan Sea

1991 ◽  
Vol 1 (4) ◽  
pp. 333-341 ◽  
Author(s):  
E. Garcia-Ladona ◽  
S. Djenidi
Keyword(s):  
Gravity Model ◽  
Reduced Gravity

Analysis of the isopycnal advection in the Lofoten basin (the Norwegian sea)

2021 ◽  
Author(s):  
Elena V. Novoselova ◽  
Tatyana V. Belonenko ◽  
Aleksandr M. Fedorov
Keyword(s):  
Deep Convection ◽  
Deep Ocean ◽  
Great Depth ◽  
Atlantic Water ◽  
Reanalysis Data ◽  
Surrounding Water ◽  
Norwegian Sea ◽  
Maximal Depth ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction

<p>The Lofoten Basin in the Norwegian Sea is a real reservoir of the Atlantic Waters. The shape of the Basin in the form of a bowl and a great depth with its monotonous increase to the centre results in the Atlantic Water gradually deepen and fill the Basin. The deepening of the Atlantic Waters in the Lofoten Basin determines not only the structure of its waters but also the features of the ocean-atmosphere interaction. Flowing through the transit regions, the Atlantic Waters lose heat to the atmosphere, mix with the surrounding water masses and undergo a transformation, which causes the formation of deep ocean waters. At the same time, the heat input with the Atlantic waters significantly exceeds its loss to the atmosphere in the Lofoten Basin.</p><p>We study isopycnal advection and diapycnal mixing in the Lofoten Basin. We use the GLORYS12V1 oceanic reanalysis data and analyze four isosteric δ-surfaces. We also calculate the depth of their location. We establish that δ-surfaces have the slope eastward with maximal deepening where the quasi-permanent Lofoten Vortex is located. We analyze the temperature distribution on the isosteric δ-surfaces as well as the interannual and seasonal variability of their location depth.</p><p>The maximal depth on the isosteric surfaces is observed in 2010, which is known as the year of the largest mixed layer depths in the Lofoten Basin according to the ARGO buoys. We demonstrate the same correspondence to in 2000, 2010, 2013.</p><p>The maximal depth on the isosteric surfaces is observed is reached in summer. The maximal areas with the greatest depths also are observed in summer in contrast to a minimum in winter. This means certain inertia of changes in the thermohaline characteristics of Atlantic Waters as well as a shift of 1-2 seasons of the influence of deep convection on isosteric surfaces.</p><p>It is shown that isopycnal advection in the Lofoten Basin makes a significant contribution to its importance as the main thermal reservoir of the Nordic Seas.</p>

scholarly journals Declining silicate concentrations in the Norwegian and Barents Seas

2012 ◽  
Vol 69 (2) ◽  
pp. 208-212 ◽  
Author(s):  
Francisco Rey
Keyword(s):  
North Atlantic ◽  
Relative Proportion ◽  
Atlantic Water ◽  
Water Masses ◽  
Source Water ◽  
Marine Science ◽  
Norwegian Sea

Abstract Rey, F. 2012. Declining silicate concentrations in the Norwegian and Barents Seas. – ICES Journal of Marine Science, 69: 208–212. Since 1990, a decline in silicate concentrations together with increasing salinities has been observed in the Atlantic water of the Norwegian and Barents Seas. This decline in silicate has been found to be related to the relative proportion in which eastern and western source water masses from the northeastern North Atlantic enter the Norwegian Sea.

scholarly journals Heat content in the Norwegian Sea, 1995–2010

2012 ◽  
Vol 69 (5) ◽  
pp. 826-832 ◽  
Author(s):  
Øystein Skagseth ◽  
Kjell Arne Mork
Keyword(s):  
Heat Content ◽  
Atlantic Water ◽  
Heat Fluxes ◽  
Gradual Transition ◽  
Absolute Maximum ◽  
Nordic Seas ◽  
Norwegian Sea ◽  
Ocean Climate ◽  
The North ◽  
Spatio Temporal

Abstract Skagseth, Ø., and Mork, K. A. 2012. Heat content in the Norwegian Sea, 1995–2010. – ICES Journal of Marine Science, 69: 826–832. Spatio-temporal hydrographic data from the Nordic Seas during spring over the period 1995–2010 were investigated in terms of the relative heat content (RHC) above the density surface σt = 27.9, chosen to capture the changes in Atlantic water (AW). Focusing on the Atlantic (eastern) domain of the Nordic Seas, negative anomalies dominated the early part of the series. There was then a gradual transition towards an absolute maximum in 2003/2004, followed by a small reduction with positive values for the period ending in 2010. The maps clearly reveal the events of propagating signals. The variability is regionally comparable, but the persistence on a year-to-year basis is higher in the Lofoten Basin than in the Norwegian Basin. Compared with other studies, in this study, the estimated trend in the RHC of the Nordic Seas was larger than for the global mean and the North Atlantic. The warming of the Nordic Seas derives mainly from the advection of warmer inflowing AW and less from changes in local air–sea heat fluxes. The importance of advection suggests that the variability of the Norwegian Sea's ocean climate can, to a large extent, be predicted based on the observed hydrographic conditions.

scholarly journals Vertical Migration of Pelagic and Mesopelagic Scatterers From ADCP Backscatter Data in the Southern Norwegian Sea

2021 ◽  
Vol 7 ◽  
Author(s):  
Boris Cisewski ◽  
Hjálmar Hátún ◽  
Inga Kristiansen ◽  
Bogi Hansen ◽  
Karin Margretha H. Larsen ◽  
...  
Keyword(s):  
Vertical Migration ◽  
Complex Dynamics ◽  
Atlantic Water ◽  
Vertical Movement ◽  
Light Cycle ◽  
Photic Zone ◽  
Calanoid Copepods ◽  
Near Surface ◽  
Norwegian Sea ◽  
Deep Layers

Records of backscatter and vertical velocity obtained from moored Acoustic Doppler Current Profilers (ADCP) enabled new insights into the dynamics of deep scattering layers (DSLs) and diel vertical migration (DVM) of mesopelagic biomass between these deep layers and the near-surface photic zone in the southern Norwegian Sea. The DSL exhibits characteristic vertical movement on inter-monthly time scales, which is associated with undulations of the main pycnocline between the warm Atlantic water and the underlying colder water masses. Timing of the DVM is closely linked to the day-night light cycle—decent from the photic zone just before sunrise and ascent immediately after sunset. Seasonal variations are also evident, with the highest DVM activity and lowest depth averaged mean volume backscatter strength (MVBS) during spring. This suggests that both oceanographic and optical conditions are driving the complex dynamics of pelagic and mesopelagic activity in this region. We hypothesize that the increased abundance of calanoid copepods in the near-surface layer during spring increases the motivation for vertical migration of pelagic and mesopelagic species, which therefore can explain the increased DVM activity during this season.

scholarly journals The Norwegian Sea Gyre – A Regulator of Iceland-Scotland Ridge Exchanges

2021 ◽  
Vol 8 ◽  
Author(s):  
Hjálmar Hátún ◽  
Léon Chafik ◽  
Karin Margretha Húsgarð Larsen
Keyword(s):  
Regional Climate ◽  
Large Body ◽  
Atlantic Water ◽  
Meridional Overturning Circulation ◽  
Intermediate Water ◽  
Norwegian Sea ◽  
Sea Surface Heights ◽  
Meridional Overturning ◽  
Standard Section ◽  
Key Aspects

The Norwegian Sea gyre (NSG) is a large body of Arctic intermediate water and deep dense overflow waters, which circulate counterclockwise within the Norwegian Sea. Argo float trajectories presented in this study suggest that the NSG attains its strongest and most focused flow downstream of a confluence of subarctic waters from the Iceland Sea and the Jan Mayen Ridge at steep bathymetry north of the Faroe slope. Based on hydrographic data from a meridional standard section across this flow (1988 to present), the first baroclinic estimate of the NSG circulation strength is provided. We, furthermore, show that the NSG circulation regulates key aspects of both the poleward Atlantic Water (AW) currents and the equatorward near-bottom and mid-depth flows in the Norwegian Sea – the main arteries of the Meridional Overturning Circulation. More specifically, we demonstrate close links between the NSG circulation and (i) the observed Faroe Bank Channel Overflow (FBCO) transport, (ii) variable depth of the main thermocline separating AW from the underlying colder and denser subarctic water masses, and (iii) satellite-derived sea-surface heights (SSHs) in the southern Nordic Seas. In general, a strong NSG and weak FBCO transport are associated with an uplifted thermocline and depressed SSH. Along a narrow band near the Norwegian and Shetland slopes, a strong NSG – oppositely – links to a depressed interface. Daily records of the FBCO transport, and satellite altimetry in a sensitive region north of the Iceland-Faroe Ridge, complement our hydrographic monitoring of the NSG strength. Together these records constitute valuable indicators for aspects of the Norwegian Sea physical oceanography, which likely have an impact on regional climate, ecology and biological productivity.

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