scholarly journals Hudson Strait ice dam collapse: An explanation for the onset of the Younger Dryas cold climate in Europe in only one year

2021 ◽  
Vol 18 ◽  
pp. 1-11
Author(s):  
Robert Glenn Johnson
Keyword(s):  
Stream Flow ◽  
Younger Dryas ◽  
Cold Climate ◽  
Hudson Bay ◽  
Glacial Ice ◽  
Ice Stream ◽  
Climate Event ◽  
Southern Half ◽  
East End ◽  
One Year

The Younger Dryas cold climate event in Europe began abruptly at about 12,679 years BP. The abruptness of the onset was caused by the rapid collapse of a dynamic ice dam that had existed because of ice stream flow across the east end of Hudson Strait in northern Canada. The resulting flood of icebergs into the southern half of the Northern Gyre adjacent to the Gulf Stream converted western Europe’s mild climate to an arctic climate. The collapse event was caused by the last large accumulation of glacial ice in the thick ice dome of Hudson Bay. The accumulation created a pressure gradient that forced an ice stream flow eastward in Hudson Strait. A highly saline sub-glacial lake had formed earlier in the western part of the strait. The ice stream flow entrained saline lake water in a network of channels at the seabed between the lake and the ice dam, melting and extending the network eventually to and beneath the ice dam. This detached much of the ice dam from its frozen bed and caused its catastrophic collapse and the onset of the Younger Dryas in only one year.

scholarly journals A Race for Ice Discharge between Ice Streams on Glaciated Continental Shelves

2018 ◽  
Author(s):  
Etienne Brouard ◽  
Patrick Lajeunesse
Keyword(s):  
Stream Flow ◽  
Baffin Island ◽  
Stream Networks ◽  
Ice Streams ◽  
Glacial Ice ◽  
Ice Stream ◽  
Continental Shelves ◽  
Ice Sheet Mass Balance ◽  
Global Sea Level ◽  
Flow Switch

Abstract. Ice stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice stream networks have major impact on ice sheet mass balance and global sea level. However, the mechanisms controlling ice stream switching remain poorly understood. Here, we report a flow-switch in an ice stream system that occurred during the Pliocene-Pleistocene on the northeastern Baffin Island shelf (Arctic Canada) through glacial erosion of a marginal trough. We find that up-ice propagation of ice streams through marginal troughs can lead to the piracy of neighbouring ice-catchments, which in turn induce an adjacent ice stream flow-switch and shutdown. Similar trough systems observed on many other glaciated continental shelves may be the product of such a competition for ice discharge between catchments.

Unstable ice stream in Greenland during the Younger Dryas cold event

Geology ◽  
2014 ◽  
Vol 42 (9) ◽  
pp. 759-762 ◽  
Author(s):  
Vincent Rinterknecht ◽  
Vincent Jomelli ◽  
Daniel Brunstein ◽  
Vincent Favier ◽  
Valérie Masson-Delmotte ◽  
...  
Keyword(s):  
Younger Dryas ◽  
Cold Event ◽  
Ice Stream

scholarly journals Climate bifurcation during the last deglaciation

2012 ◽  
Vol 8 (1) ◽  
pp. 321-348 ◽  
Author(s):  
T. M. Lenton ◽  
V. N. Livina ◽  
V. Dakos ◽  
M. Scheffer
Keyword(s):  
Climate Variability ◽  
Early Warning ◽  
Bifurcation Point ◽  
Younger Dryas ◽  
Cold Climate ◽  
Meridional Overturning Circulation ◽  
Last Deglaciation ◽  
Overturning Circulation ◽  
Slowing Down ◽  
The Last Deglaciation

Abstract. The last deglaciation was characterised by two abrupt warming events, at the start of the Bølling-Allerød and at the end of the Younger Dryas, but their underlying causes are unclear. Some abrupt climate changes may involve gradual forcing past a bifurcation point, in which a prevailing climate state loses its stability and the climate tips into an alternative state, providing an early warning signal in the form of slowing responses to perturbations. However, the abrupt Dansgaard-Oeschger (DO) events during the last ice age were probably triggered by stochastic fluctuations without bifurcation or early warning, and whether the onset of the Bølling-Allerød (DO event 1) was preceded by slowing down or not is debated. Here we show that the interval from the Last Glacial Maximum to the end of the Younger Dryas, as recorded in three Greenland ice cores with two different climate proxies, was accompanied by a robust slowing down in climate dynamics and an increase in climate variability, consistent with approaching bifurcation. Prior to the Bølling warming there was a robust increase in climate variability but no consistent slowing down signal, suggesting this abrupt change was probably triggered by a stochastic fluctuation. The Bølling warming marked a distinct destabilisation of the climate system, which excited an internal mode of variability in Atlantic meridional overturning circulation strength, causing multi-centennial climate fluctuations. There is some evidence for slowing down in the transition to and during the Younger Dryas. We infer that a bifurcation point was finally approached at the end of the Younger Dryas, in which the cold climate state, with weak Atlantic overturning circulation, lost its stability, and the climate tipped irreversibly into a warm interglacial state. The lack of a large triggering perturbation at the end of the Younger Dryas, and the fact that subsequent meltwater perturbations did not cause sustained cooling, support the bifurcation hypothesis.

scholarly journals Is Ice-Stream Evolution Revealed By Satellite Imagery?

1990 ◽  
Vol 14 ◽  
pp. 273-277 ◽  
Author(s):  
S.N. Stephenson ◽  
R.A. Bindschadler
Keyword(s):  
Stream Flow ◽  
Temporal Evolution ◽  
Thematic Mapper ◽  
Landsat Thematic Mapper ◽  
West Antarctica ◽  
Ice Streams ◽  
Ice Flow ◽  
Ice Shelves ◽  
Ice Stream ◽  
Grounding Line

Ten Landsat Thematic Mapper images together show Ice Streams E, D and most of Ice Stream C on Siple Coast, West Antarctica. The images are interpreted to reveal aspects of both spatial and temporal evolution of the ice streams. Onset of ice-stream flow appears to occur at distributed sites within the ice-stream catchment, and the apparent enhanced flow continues in channels until they join, forming the main ice stream. Most crevassing on these ice streams is associated with features of horizontal dimensions between 5 and 20 km. We suggest these features are caused by bed structures which may be an important source of restraint to ice flow, similar to ice rumples on ice shelves. A pattern of features near the grounding line of the now-stagnant Ice Stream C are interpreted as having formed because there was a period of reduced flux before the ice stream stopped.

scholarly journals Is Ice-Stream Evolution Revealed By Satellite Imagery?

1990 ◽  
Vol 14 ◽  
pp. 273-277 ◽  
Author(s):  
S.N. Stephenson ◽  
R.A. Bindschadler
Keyword(s):  
Stream Flow ◽  
Temporal Evolution ◽  
Thematic Mapper ◽  
Landsat Thematic Mapper ◽  
West Antarctica ◽  
Ice Streams ◽  
Ice Flow ◽  
Ice Shelves ◽  
Ice Stream ◽  
Grounding Line

Ten Landsat Thematic Mapper images together show Ice Streams E, D and most of Ice Stream C on Siple Coast, West Antarctica. The images are interpreted to reveal aspects of both spatial and temporal evolution of the ice streams. Onset of ice-stream flow appears to occur at distributed sites within the ice-stream catchment, and the apparent enhanced flow continues in channels until they join, forming the main ice stream. Most crevassing on these ice streams is associated with features of horizontal dimensions between 5 and 20 km. We suggest these features are caused by bed structures which may be an important source of restraint to ice flow, similar to ice rumples on ice shelves. A pattern of features near the grounding line of the now-stagnant Ice Stream C are interpreted as having formed because there was a period of reduced flux before the ice stream stopped.

scholarly journals The location of the grounding zone of Evans Ice Stream, Antarctica, investigated using SAR interferometry and modelling

2009 ◽  
Vol 50 (52) ◽  
pp. 35-40 ◽  
Author(s):  
Helena J. Sykes ◽  
Tavi Murray ◽  
Adrian Luckman
Keyword(s):  
Stream Flow ◽  
Elastic Beam ◽  
Tidal Height ◽  
Sar Interferometry ◽  
Beam Model ◽  
West Antarctica ◽  
Tidal Model ◽  
Tidal Forcing ◽  
Ice Stream ◽  
Grounding Line

AbstractEvans Ice Stream, West Antarctica, has five tributaries and a complex grounding zone. The grounding zone of Evans Ice Stream, between the landward and seaward limits of tidal flexing, was mapped using SAR interferometry. The width of the mapped grounding zone was compared with that derived from an elastic beam model, and the tidal height changes derived from interferometry were compared with the results of a tidal model. Results show that in 1994 and 1996 the Evans grounding zone was located up to 100 km upstream of its location in the BEDMAP dataset. The grounding line of Evans Ice Stream is subjected to 5 m vertical tidal forcing, which would clearly affect ice-stream flow.

Treatment of gully pot liquor containing heavy metals with constructed wetlands in Scotland

2005 ◽  
Vol 51 (9) ◽  
pp. 251-258 ◽  
Author(s):  
M. Scholz ◽  
P. Anderson ◽  
B.I. Forman
Keyword(s):  
Heavy Metals ◽  
Oxygen Demand ◽  
Copper Nitrate ◽  
Common Reed ◽  
Cold Climate ◽  
Water Runoff ◽  
Treatment Standards ◽  
Copper Nickel ◽  
One Year ◽  
Nickel Leaching

The aim of this investigation was to assess the treatment efficiencies for gully pot liquor of 12 experimental vertical-flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (Common Reed) and filter media of different adsorption capacities in a cold climate. Seven of the twelve filters received inflow water spiked with heavy metals. For one year, hydrated copper nitrate and hydrated nickel nitrate were added to sieved gully pot liquor to simulate contaminated primary treated storm water runoff. The inflow concentrations for dissolved copper, nickel and nitrate-nitrogen were approximately 1.0, 1.0 and 1.45 mg/l, respectively, which represent mean loading rates of 0.063 g/m2/d for Filters 2 and 7 to 11, and 0.115 g/m2/d for Filter 12. For these filters receiving metals, an obvious breakthrough of dissolved nickel was recorded after road gritting and salting during winter. Sodium chloride was responsible for nickel leaching. Reductions of copper, nickel, biochemical oxygen demand and suspended solids were frequently insufficient compared to international secondary wastewater treatment standards. Moreover, the overall filtration performance for all filters was similar.

scholarly journals Temperature Measurements on a Solar and Low Enthalpy Geothermal Open-Air Asphalt Surface Platform in a Cold Climate Region

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 979 ◽  
Author(s):  
Caner Çuhac ◽  
Anne Mäkiranta ◽  
Petri Välisuo ◽  
Erkki Hiltunen ◽  
Mohammed Elmusrati
Keyword(s):  
Heat Flux ◽  
Urban Areas ◽  
Storage System ◽  
Energy Resource ◽  
Cold Climate ◽  
Solar Irradiation ◽  
Solar Heat ◽  
Heat Collector ◽  
One Year

Solar heat, already captured by vast asphalt fields in urban areas, is potentially a huge energy resource. The vertical soil temperature profile, i.e., low enthalpy geothermal energy, reveals how efficiently the irradiation is absorbed or radiated back to the atmosphere. Measured solar irradiation, heat flux on the asphalt surface and temperature distribution over a range of depths describe the thermal energy from an asphalt surface down to 10 m depth. In this study, those variables were studied by long-term measurements in an open-air platform in Finland. To compensate the nighttime heat loss, the accumulated heat on the surface should be harvested during the sunny daytime periods. A cumulative heat flux over one year from asphalt to the ground was 70% of the cumulative solar irradiance measured during the same period. However, due to the nighttime heat losses, the net heat flux during 5 day period was only 18% of the irradiance in spring, and was negative during autumn, when the soil was cooling. These preliminary results indicate that certain adaptive heat transfer and storage mechanisms are needed to minimize the loss and turn the asphalt layer into an efficient solar heat collector connected with a seasonal storage system.

Recent Dynamics of Subarctic Dunes as Determined by Tree-Ring Analysis of White Spruce, Hudson Bay, Québec

1992 ◽  
Vol 38 (3) ◽  
pp. 316-330 ◽  
Author(s):  
Pierre Marin ◽  
Louise Filion
Keyword(s):  
Tree Ring ◽  
Migration Rate ◽  
Accumulation Rate ◽  
Average Rate ◽  
Sand Dunes ◽  
White Spruce ◽  
Growth Patterns ◽  
Cold Climate ◽  
Eastern Coast ◽  
Hudson Bay

AbstractThe radial-growth patterns of white spruce were studied on a number of trees growing in subarctic dunes along the eastern coast of Hudson Bay to calculate the rates of accumulation, erosion, and migration of cold-climate sand dunes. The average rate of sand accumulation in sheltered dunes (forest sites) was 2.5 to 3.3 cm/yr, which is two to three times lower than in highly exposed dunes with a rate of sedimentation of 7.65 cm/yr. The average erosion rate was 1.4–1.7 cm/yr, about two times lower than the accumulation rate. The migration rate of sheltered dunes was 18 to 30 cm/yr, three to five times lower than for an exposed dune which advanced at a speed of 74 cm/yr. This migration rate established for highly exposed dunes in the Subarctic with tree-ring methods is about 10 times lower than that established for a barchan in the Sahara with other methods.

scholarly journals Sensitivity of the divide position at Siple Dome, West Antarctica, to boundary forcing

1998 ◽  
Vol 27 ◽  
pp. 207-214 ◽  
Author(s):  
N. A. Nereson ◽  
R. C. A. Hindmarsh ◽  
C. F. Raymond
Keyword(s):  
Time Scales ◽  
Steady Increase ◽  
West Antarctica ◽  
Ice Streams ◽  
Accumulation Pattern ◽  
The Past ◽  
Ice Stream ◽  
Siple Dome ◽  
Climate Event ◽  
Short Time

A linearized perturbation about a two-dimensional Vialov-Nyc ice-shect profile is used to investigate the sensitivity of the divide position at Siple Dome, West Antarctica, to small changes in the accumulation pattern and in the elevation of its lateral boundaries at the margins of Ice Streams C and D. Relaxation time-scales for the ice-sheet surface and divide position are derived from the perturbation theory. For Siple Dome, these time-scales are short: 450 800 years for surface adjustment, and 200-350 years for divide position adjustment. These short time-scales indicate that Siple Dome responds quickly to forcing at its boundaries. Therefore, the recent migration of the Siple Dome divide (determined from previous work) is probably a response to an ongoing, sustained forcing rather than a response to a long-past climate event such as the transition from the Last Glacial Maximum to the Holocene. Based on our analysis, the inferred rate of migration of the Siple Dome divide could be attained by: (1) a steady increase in the south north spatial accumulation gradient of 0.1-1.5 × 10−9 a −2, or (2) a steady increase (decrease) in elevation of the Siple Dome lateral boundary adjacent to a relict margin of Ice Stream D (Ice Stream C) of 0.005-0.040 m a−1 over the past several thousand years. The required forcing is quite small, and suggests that major changes in the configuration of Ice Streams C and D associated with major changes in the elevation at boundaries of Siple Dome have not occurred over the past several thousand years.

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