Floating Glacial Ice Caps in the Arctic Ocean

A global coupled atmosphere–ocean model is used to examine the hydrologic cycle of the Arctic Ocean. The model has a horizontal resolution of 4° × 5°, nine vertical layers in the atmosphere and 13 in the ocean. River discharge into the Arctic Ocean is included by allowing runoff from each continental grid box to flow downstream according to a specified direction file and a speed that depends on topography. A 74 year control simulation of the present climate is used to examine variability of the hydrologic cycle, including precipitation, sea ice, glacial ice and river discharge. A 74 year transient simulation in which atmospheric CO2increases each year at a compound rate оf 1% is then used to examine potential changes in the hydrologic cycle. Among these changes are a 4°C increase in mean annual surface air temperature in the Arctic Ocean, a decrease in ice cover which begins after 35 years, and increases in river discharge and cloud cover. There is little change in the net difference between precipitation and evaporation. Also in the transient simulation, glacial ice on Greenland decreases relative to the control.

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Ice Lithologies and Structure of Ice Island Arlis II

Journal of Glaciology ◽

10.3189/s0022143000028550 ◽

1964 ◽

Vol 5 (37) ◽

pp. 17-38 ◽

Cited By ~ 1

Author(s):

David D. Smith

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Fresh Water ◽

Structural Features ◽

The Arctic ◽

Glacial Ice ◽

Water Ice ◽

Central Block ◽

The Arctic Ocean

AbstractIce island ARLIS II, which is adrift in the Arctic Ocean, is a 1.3 km. wide and 3.8 km. long fragment of shelf ice 12–25 m. thick, which preserves several structural features heretofore undescribed in ice. The island is composed of an irregular central block of foliated, locally debris-rich, grey glacial ice bordered in part by extensive areas of stratified bluish sea ice. The central block contains a series of narrow, elongate, sub-parallel dike-like septa of massive fresh-water ice and a large tongue-like body of tightly folded, coarse banded ice. Both the septa and the tongue cut across the foliation and debris zones of the grey ice.The margins of the central block are penetrated by a series of elongate, crudely wedge-shaped re-entrants occupied by salients of bluish sea ice. Two broad, arch-like plunging anticlines deform the stratified sea ice along one margin of the block.The foliation and debris zones in the glacial ice are relict features inherited from the source glacier. The septa formed as crevasse and basal fracture fills. Salients represent fills formed in the irregular re-entrants along the margins of the glacial ice mass. The tongue of tightly folded, banded ice represents an earlier generation salient deformed by compressive forces as the fill built up. The broad anticlines are apparently the result of warping in response to differential ablation but the small, tight plunging folds on their noses and limbs are probably the result of compressive forces.

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Ice Lithologies and Structure of Ice Island Arlis II

Journal of Glaciology ◽

10.1017/s0022143000028550 ◽

1964 ◽

Vol 5 (37) ◽

pp. 17-38 ◽

Cited By ~ 22

Author(s):

David D. Smith

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Fresh Water ◽

Structural Features ◽

The Arctic ◽

Glacial Ice ◽

Water Ice ◽

Central Block ◽

The Arctic Ocean

Abstract Ice island ARLIS II, which is adrift in the Arctic Ocean, is a 1.3 km. wide and 3.8 km. long fragment of shelf ice 12–25 m. thick, which preserves several structural features heretofore undescribed in ice. The island is composed of an irregular central block of foliated, locally debris-rich, grey glacial ice bordered in part by extensive areas of stratified bluish sea ice. The central block contains a series of narrow, elongate, sub-parallel dike-like septa of massive fresh-water ice and a large tongue-like body of tightly folded, coarse banded ice. Both the septa and the tongue cut across the foliation and debris zones of the grey ice. The margins of the central block are penetrated by a series of elongate, crudely wedge-shaped re-entrants occupied by salients of bluish sea ice. Two broad, arch-like plunging anticlines deform the stratified sea ice along one margin of the block. The foliation and debris zones in the glacial ice are relict features inherited from the source glacier. The septa formed as crevasse and basal fracture fills. Salients represent fills formed in the irregular re-entrants along the margins of the glacial ice mass. The tongue of tightly folded, banded ice represents an earlier generation salient deformed by compressive forces as the fill built up. The broad anticlines are apparently the result of warping in response to differential ablation but the small, tight plunging folds on their noses and limbs are probably the result of compressive forces.

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Climate change and the Arctic hydrologic cycle as calculated by a global coupled atmosphere–ocean model

Annals of Glaciology ◽

10.3189/s0260305500015652 ◽

1995 ◽

Vol 21 ◽

pp. 91-95

Author(s):

James R. Miller ◽

Gary L. Russell

Keyword(s):

Arctic Ocean ◽

River Discharge ◽

Surface Air Temperature ◽

Horizontal Resolution ◽

Ocean Model ◽

Hydrologic Cycle ◽

Transient Simulation ◽

The Arctic ◽

Glacial Ice ◽

The Arctic Ocean

A global coupled atmosphere–ocean model is used to examine the hydrologic cycle of the Arctic Ocean. The model has a horizontal resolution of 4° × 5°, nine vertical layers in the atmosphere and 13 in the ocean. River discharge into the Arctic Ocean is included by allowing runoff from each continental grid box to flow downstream according to a specified direction file and a speed that depends on topography. A 74 year control simulation of the present climate is used to examine variability of the hydrologic cycle, including precipitation, sea ice, glacial ice and river discharge. A 74 year transient simulation in which atmospheric CO2 increases each year at a compound rate оf 1% is then used to examine potential changes in the hydrologic cycle. Among these changes are a 4°C increase in mean annual surface air temperature in the Arctic Ocean, a decrease in ice cover which begins after 35 years, and increases in river discharge and cloud cover. There is little change in the net difference between precipitation and evaporation. Also in the transient simulation, glacial ice on Greenland decreases relative to the control.

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Microfeatures of modern sea-ice-rafted sediment and implications for paleo-sea-ice reconstructions

Annals of Glaciology ◽

10.3189/2015aog69a586 ◽

2015 ◽

Vol 56 (69) ◽

pp. 83-93 ◽

Cited By ~ 13

Author(s):

Kristen St John ◽

Sandra Passchier ◽

Brooke TantillO ◽

Dennis Darby ◽

Lance Kearns

Keyword(s):

Sediment Transport ◽

Sea Ice ◽

Arctic Ocean ◽

Chemical Weathering ◽

The Arctic ◽

Discriminate Analysis ◽

Glacial Ice ◽

Coastal Marine ◽

The Arctic Ocean ◽

Glacial Processes

AbstractDistinguishing sea-ice-rafted debris (SIRD) from iceberg-rafted debris is crucial to an interpretation of ice-rafting history; however, there are few paleo-sea-ice proxies. This study characterizes quartz grain microfeatures of modern SIRD from the Arctic Ocean, and compares these results with microfeatures from representative glacial deposits to potentially differentiate SIRD from ice-rafted sediments which have been recently subjected to glacial processes. This allows us to evaluate the use of grain microfeatures as a paleo-sea-ice proxy. SIRD grains were largely subrounded, with medium relief, pervasive silica dissolution and a high abundance of breakage blocks and microlayering. The glacial grains were more angular, with lower relief and higher abundances of fractures and striations/gouges. Discriminate analysis shows a distinct difference between SIRD and glacial grains, with ˂7% of the SIRD grains containing typical glacial microtextures, suggesting this method is a useful means of inferring paleo-sea-ice presence in the marine record. We propose that differences in microfeatures of SIRD and glacial ice-rafted debris reflect differences in sediment transport and weathering histories. Sediment transported to a coastal setting and later rafted by sea ice would be subject to increased chemical weathering, whereas glaciers that calve icebergs would bypass the coastal marine environment, thus preserving their glacial signature.

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