Numerical Modeling of the Late Weichselian Svalbard-Barents Sea Ice Sheet

1995 ◽  
Vol 43 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Martin J. Siegert ◽  
Julian A. Dowdeswell
Keyword(s):  
Numerical Model ◽  
Sea Ice ◽  
Barents Sea ◽  
Ice Sheet ◽  
Ice Cover ◽  
Time Dependent ◽  
Southern Limit ◽  
Geological Evidence ◽  
Iceberg Calving ◽  
Late Weichselian

AbstractPrevious reconstructions of the ice cover of the Svalbard-Barents Sea region during the late Weichselian have ranged from small ice masses on Svalbard to complete inundation of the Barents Shelf region by an ice sheet several kilometers thick. We have used a time-dependent finite-difference numerical model to undertake a new glaciological reconstruction for the Svalbard-Barents Sea Ice Sheet over the last 30,000 yr. The numerical model requires environmental forcing functions in the form of air temperature and precipitation and their behavior with respect to altitude, together with sea-level change and an iceberg calving relation. Ice buildup on Svalbard is calculated to have begun 28,000 yr ago, and maximum dimensions were reached by 20,000 yr ago, covering Svalbard and the northwestern Barents Sea with a center of mass (1.3 km thick) around eastern Svalbard. Decay was complete by about 10,000 yr ago. The margin of the modeled ice sheet at its maximum is in good agreement with observed sea-floor morphological features, but there are discrepancies in timing between the modeled ice sheet decay and (i) a dated meltwater spike in Fram Strait and (ii) the observed rebound curves for Svalbard. An inverse approach was used to predict ice sheet decay, and it was found that increasing the rate of iceberg calving within the model produces a deglaciation some 2000 yr earlier, which is compatible with these two independent datasets. The reconstruction is also compatible with geological evidence on the isostatic response of Bjørnøya, close to the southern limit of the ice sheet, and seismically observed deposits, interpreted to be ice. proximal facies, located in the northwestern Barents Sea. Our time-dependent model reconstructions of the Svalbard-Barents Sea Ice Sheet indicate ice cover over only the northwestern Barents Sea during the late Weichselian, but this does not preclude the presence of ice derived from Fennoscandia and the Kara Sea region elsewhere in the Barents Sea.

scholarly journals Isostatic uplift in the late Weichselian Barents Sea: implications for ice-sheet growth

1996 ◽  
Vol 23 ◽  
pp. 352-358 ◽  
Author(s):  
M. J. Siegert ◽  
W. Fjeldskaar
Keyword(s):  
Barents Sea ◽  
Ice Sheet ◽  
Time Dependent ◽  
Earth Model ◽  
Novaya Zemlya ◽  
Isostatic Uplift ◽  
Franz Josef Land ◽  
Geological Information ◽  
Ice Loads ◽  
Late Weichselian

Results from a recent time-dependent ice-sheet modelling study of the late Weichselian Svalbard—Barents Sea ice sheet suggest that, under environmental conditions representative of those during the late Weichselian, ice derived solely from Svalbard may have occupied only the relatively shallow (<300 m water depth) northwestern Barents Sea, with other deeper regions remaining free of grounded ice (Siegert and Dowdeswell, 1995a). However, late Weichselian geological information from the 400 m deep Bjørnøyrenna (southern Barents Sea) indicates that grounded ice was present in an area modelled by Siegert and Dowdeswell (1995a) as free of ice (e.g. Laberg and Vorren, in press a). Isostatic uplift of the central Barents Sea may have reduced the relative sea level and hence provided a mechanism by which grounded ice could have migrated from relatively shallow regions of the Barents Sea into, previous to uplift, deeper water. We have used an isostatic Earth model to determine the geometry of an isostatic forebulge within the late Weichselian Barents Sea, caused by ice loads over Svalbard, Franz Josef Land, Novaya Zemlya and Fennoscandia. These data were then used as input to a time-dependent glaciological model, in order to predict further information about the magnitude of bedrock uplift required to allow grounded ice to flow from Svalbard into the central and southern Barents Sea. Our experiments suggest that grounded ice, originating from Svalbard, is able to form over Sentralbanken, providing that at least 60 m of uplift is achieved in the central Barents Sea. Grounded ice within Bjørnøyrenna was only predicted when the amplitude of the local forebulge exceeded 250 m.

scholarly journals Isostatic uplift in the late Weichselian Barents Sea: implications for ice-sheet growth

1996 ◽  
Vol 23 ◽  
pp. 352-358
Author(s):  
M. J. Siegert ◽  
W. Fjeldskaar
Keyword(s):  
Barents Sea ◽  
Ice Sheet ◽  
Time Dependent ◽  
Earth Model ◽  
Novaya Zemlya ◽  
Isostatic Uplift ◽  
Franz Josef Land ◽  
Geological Information ◽  
Ice Loads ◽  
Late Weichselian

Results from a recent time-dependent ice-sheet modelling study of the late Weichselian Svalbard—Barents Sea ice sheet suggest that, under environmental conditions representative of those during the late Weichselian, ice derived solely from Svalbard may have occupied only the relatively shallow (<300 m water depth) northwestern Barents Sea, with other deeper regions remaining free of grounded ice (Siegert and Dowdeswell, 1995a). However, late Weichselian geological information from the 400 m deep Bjørnøyrenna (southern Barents Sea) indicates that grounded ice was present in an area modelled by Siegert and Dowdeswell (1995a) as free of ice (e.g. Laberg and Vorren, in press a). Isostatic uplift of the central Barents Sea may have reduced the relative sea level and hence provided a mechanism by which grounded ice could have migrated from relatively shallow regions of the Barents Sea into, previous to uplift, deeper water. We have used an isostatic Earth model to determine the geometry of an isostatic forebulge within the late Weichselian Barents Sea, caused by ice loads over Svalbard, Franz Josef Land, Novaya Zemlya and Fennoscandia. These data were then used as input to a time-dependent glaciological model, in order to predict further information about the magnitude of bedrock uplift required to allow grounded ice to flow from Svalbard into the central and southern Barents Sea. Our experiments suggest that grounded ice, originating from Svalbard, is able to form over Sentralbanken, providing that at least 60 m of uplift is achieved in the central Barents Sea. Grounded ice within Bjørnøyrenna was only predicted when the amplitude of the local forebulge exceeded 250 m.

scholarly journals Polar cod in jeopardy under the retreating Arctic sea ice

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Mats Brockstedt Olsen Huserbråten ◽  
Elena Eriksen ◽  
Harald Gjøsæter ◽  
Frode Vikebø
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Keystone Species ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Biophysical Model ◽  
The Arctic ◽  
Polar Cod ◽  
Arctic Sea ◽  
Shelf Sea

Abstract The Arctic amplification of global warming is causing the Arctic-Atlantic ice edge to retreat at unprecedented rates. Here we show how variability and change in sea ice cover in the Barents Sea, the largest shelf sea of the Arctic, affect the population dynamics of a keystone species of the ice-associated food web, the polar cod (Boreogadus saida). The data-driven biophysical model of polar cod early life stages assembled here predicts a strong mechanistic link between survival and variation in ice cover and temperature, suggesting imminent recruitment collapse should the observed ice-reduction and heating continue. Backtracking of drifting eggs and larvae from observations also demonstrates a northward retreat of one of two clearly defined spawning assemblages, possibly in response to warming. With annual to decadal ice-predictions under development the mechanistic physical-biological links presented here represent a powerful tool for making long-term predictions for the propagation of polar cod stocks.

Subglacial sediment pathways and deglacial chronology of the northern Barents Sea Ice Sheet

Boreas ◽  
2017 ◽  
Vol 46 (4) ◽  
pp. 750-771 ◽  
Author(s):  
Kelly A. Hogan ◽  
Julian A. Dowdeswell ◽  
Claus-Dieter Hillenbrand ◽  
Werner Ehrmann ◽  
Riko Noormets ◽  
...  
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Ice Sheet

Palynological evidence of sea-surface conditions in the Barents Sea off northeast Svalbard during the postglacial period

2020 ◽  
pp. 1-15
Author(s):  
Camille Brice ◽  
Anne de Vernal ◽  
Elena Ivanova ◽  
Simon van Bellen ◽  
Nicolas Van Nieuwenhove
Keyword(s):  
Sea Ice ◽  
Surface Waters ◽  
Barents Sea ◽  
Ice Cover ◽  
Atlantic Water ◽  
Transitional Period ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Conditions ◽  
The Barents Sea

Abstract Postglacial changes in sea-surface conditions, including sea-ice cover, summer temperature, salinity, and productivity were reconstructed from the analyses of dinocyst assemblages in core S2528 collected in the northwestern Barents Sea. The results show glaciomarine-type conditions until about 11,300 ± 300 cal yr BP and limited influence of Atlantic water at the surface into the Barents Sea possibly due to the proximity of the Svalbard-Barents Sea ice sheet. This was followed by a transitional period generally characterized by cold conditions with dense sea-ice cover and low-salinity pulses likely related to episodic freshwater or meltwater discharge, which lasted until 8700 ± 700 cal yr BP. The onset of “interglacial” conditions in surface waters was marked by a major change in dinocyst assemblages, from dominant heterotrophic to dominant phototrophic taxa. Until 4100 ± 150 cal yr BP, however, sea-surface conditions remained cold, while sea-surface salinity and sea-ice cover recorded large amplitude variations. By ~4000 cal yr BP optimum sea-surface temperature of up to 4°C in summer and maximum salinity of ~34 psu suggest enhanced influence of Atlantic water, and productivity reached up to 150 gC/m2/yr. After 2200 ± 1300 cal yr BP, a distinct cooling trend accompanied by sea-ice spreading characterized surface waters. Hence, during the Holocene, with exception of an interval spanning about 4000 to 2000 cal yr BP, the northern Barents Sea experienced harsh environments, relatively low productivity, and unstable conditions probably unsuitable for human settlements.

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