The growth, structure and disintegration of Arctic ice shelves

Polar Record ◽  
1987 ◽  
Vol 23 (147) ◽  
pp. 631-649 ◽  
Author(s):  
Martin O. Jeffries
Keyword(s):  
Sea Ice ◽  
The Arctic ◽  
North Coast ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Growth Structure ◽  
The North ◽  
Considerable Research ◽  
The Subject ◽  
Arctic Ice

AbstractThe north coast of Ellesmere Island is the location of the only known ice shelves in the northern hemisphere. Present Arctic ice shelves are as much as 40–50 m thick and occupy sheltered fiords and embayments. These thick floating ice masses are remnants of the once-extensive Ellesmere Ice Shelf that has disintegrated since 1876–1906, when Aldrich and Peary respectively travelled along the coast. Reasons for the disintegration are not clear, but it has created many ice islands that have been known to circulate in the Arctic Ocean for 35 years or more. Both ice islands and ice shelves are readily distinguished from their surroundings by an undulating surface topography of parallel ridges and troughs up to 300 m apart. The undulations probably owe their origin to the effects of wind and meltwater. Since 1952 these large ice masses have been the subject of considerable research. Ice shelf growth began about 4000 BP, when glaciers flowed off the land and remained afloat in fiords and inlets, and sea ice grew thick and remained fast to the coast. The glacier and sea ice acted as platforms for further thickening both by surface accumulation of snow and ice and by undersurface accretion of fresh, brackish and saline ice. Although much has been learned about the growth, structure and behaviour of arctic ice shelves, questions still remain concerning ice island calving mechanisms, bottom freezing, thick sea ice growth and origins of the ridges and troughs.

scholarly journals Remote Sensing of Sea-Ice Growth and Melt-Pool Evolution, Milne Ice Shelf, Ellesmere Island, Canada

1987 ◽  
Vol 9 ◽  
pp. 145-150 ◽  
Author(s):  
Martin O. Jeffries ◽  
William M. Sackinger ◽  
Harold V. Serson
Keyword(s):  
Sea Ice ◽  
Drainage System ◽  
Outer Part ◽  
The Arctic ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Ice Growth ◽  
Radar Images ◽  
Melt Pool ◽  
Arctic Ice

Periodically since 1950, air photographs and SLAR images have been taken of the Arctic ice shelves. The study of air photographs and SLAR images of the outer part of Milne Ice Shelf had three aims: (1) to map losses and ice re-growth at the shelf front, (2) to map the evolution of melt pools on shelf ice and multi-year land-fast sea ice, and (3) to assess the usefulness of air photographs and SLAR for these purposes. For mapping of ice calvings and subsequent sea-ice growth, both air photographs and radar images have been used sucessfully. However, air photographs are better than radar for mapping ice-surface features. The ridge-and-trough systems that characterize the surface of the ice shelf and old sea ice are clearly visible on each type of imagery but, because of their larger scale, air photographs proved to be most useful for a study of melt-pool evolution. The orientation of the melt pools is parallel to the prevailing winds which drive water along the troughs. The drainage system evolves by a process of elongation and coalesence.

scholarly journals Survey and Mapping of Recent Ice Shelf Changes and Landfast Sea Ice Growth Along the North Coast of Ellesmere Island, NWT, Canada

1986 ◽  
Vol 8 ◽  
pp. 96-99 ◽  
Author(s):  
M.O. Jeffries ◽  
H.V. Serson
Keyword(s):  
Sea Ice ◽  
Ellesmere Island ◽  
North Coast ◽  
Ice Shelf ◽  
Negative Mass ◽  
Ice Shelves ◽  
The North ◽  
Landfast Ice ◽  
Melt Water ◽  
Landfast Sea Ice

Ground and aerial surveys along the north coast of Ellesmere Island confirm that a considerable area of shelf ice remains, although it is not as extensive as it once was due to periodic ice island calvings. However, the lost ice shelf is quickly replaced by landfast sea ice. The sea ice often persists for many years and thickens sufficiently to be considered as the restoration of former ice shelf. The landfast ice quickly assumes an undulating topography, similar to the ice shelves, the development of which is encouraged by melt water and wind action. Even under the present conditions of negative mass balance, the sea ice reaches considerable, undeformed thicknesses. The thick sea ice forming today could be the precursor of an expansion of the ice shelves.

scholarly journals Survey and Mapping of Recent Ice Shelf Changes and Landfast Sea Ice Growth Along the North Coast of Ellesmere Island, NWT, Canada

1986 ◽  
Vol 8 ◽  
pp. 96-99 ◽  
Author(s):  
M.O. Jeffries ◽  
H.V. Serson
Keyword(s):  
Sea Ice ◽  
Ellesmere Island ◽  
North Coast ◽  
Ice Shelf ◽  
Negative Mass ◽  
Ice Shelves ◽  
The North ◽  
Landfast Ice ◽  
Melt Water ◽  
Landfast Sea Ice

Ground and aerial surveys along the north coast of Ellesmere Island confirm that a considerable area of shelf ice remains, although it is not as extensive as it once was due to periodic ice island calvings. However, the lost ice shelf is quickly replaced by landfast sea ice. The sea ice often persists for many years and thickens sufficiently to be considered as the restoration of former ice shelf. The landfast ice quickly assumes an undulating topography, similar to the ice shelves, the development of which is encouraged by melt water and wind action. Even under the present conditions of negative mass balance, the sea ice reaches considerable, undeformed thicknesses. The thick sea ice forming today could be the precursor of an expansion of the ice shelves.

North Greenland ice islands

Polar Record ◽  
1989 ◽  
Vol 25 (154) ◽  
pp. 207-212 ◽  
Author(s):  
A. K. Higgins
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Surface Topography ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Ice Shelves ◽  
The North ◽  
The Arctic Ocean ◽  
North Greenland

AbstractLarge tabular icebergs derived from the glaciers which drain the north fringe of Greenland's Inland Iceoccur in many North Greenland fjords. Many have undulating surface topography resembling that of the ice islands calved from Ellesmere Island ice shelves. Semi-permanent sea ice in North Greenland fjords often prevents the escape of bergs, except in exceptional summers several decades apart, when the fjord ice melts completely and some bergs may reach the Arctic Ocean. Other possible sources for ice islands are small ice shelves and local glaciers along the north coast of Greenland.

scholarly journals Remote Sensing of Sea-Ice Growth and Melt-Pool Evolution, Milne Ice Shelf, Ellesmere Island, Canada

1987 ◽  
Vol 9 ◽  
pp. 145-150
Author(s):  
Martin O. Jeffries ◽  
William M. Sackinger ◽  
Harold V. Serson
Keyword(s):  
Sea Ice ◽  
Drainage System ◽  
Outer Part ◽  
The Arctic ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Ice Growth ◽  
Radar Images ◽  
Melt Pool ◽  
Arctic Ice

Periodically since 1950, air photographs and SLAR images have been taken of the Arctic ice shelves. The study of air photographs and SLAR images of the outer part of Milne Ice Shelf had three aims: (1) to map losses and ice re-growth at the shelf front, (2) to map the evolution of melt pools on shelf ice and multi-year land-fast sea ice, and (3) to assess the usefulness of air photographs and SLAR for these purposes. For mapping of ice calvings and subsequent sea-ice growth, both air photographs and radar images have been used sucessfully. However, air photographs are better than radar for mapping ice-surface features. The ridge-and-trough systems that characterize the surface of the ice shelf and old sea ice are clearly visible on each type of imagery but, because of their larger scale, air photographs proved to be most useful for a study of melt-pool evolution. The orientation of the melt pools is parallel to the prevailing winds which drive water along the troughs. The drainage system evolves by a process of elongation and coalesence.

scholarly journals Using Arctic ice mass balance buoys for evaluation of modelled ice energy fluxes

2019 ◽  
Author(s):  
Alex West ◽  
Mat Collins ◽  
Ed Blockley
Keyword(s):  
Sea Ice ◽  
Mass Balance ◽  
Climate Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Extent ◽  
The North ◽  
Energy Evaluation ◽  
Ice Mass Balance ◽  
Arctic Ice

Abstract. Arctic sea ice has declined rapidly over recent decades. Models predict that the Arctic will be nearly ice-free by mid-century, but the spread in predictions of sea ice extent is currently large. The reasons for this spread are poorly understood, partly due to a lack of observations with which the processes by which Arctic atmospheric and oceanic forcing affect sea ice state can be examined. In this study, a method of estimating fluxes of top melt, top conduction, basal conduction and ocean heat flux from Arctic ice mass balance buoy elevation and temperature data is presented. The derived fluxes are used to evaluate modelled fluxes from the coupled climate model HadGEM2-ES in two densely sampled regions of the Arctic, the North Pole and Beaufort Sea. The evaluation shows the model to overestimate the magnitude of summer top melting fluxes, and winter conductive fluxes, results which are physically consistent with an independent sea ice and surface energy evaluation of the same model.

scholarly journals Atmospheric moisture transport: the bridge between ocean evaporation and Arctic ice melting

2015 ◽  
Vol 6 (2) ◽  
pp. 583-589 ◽  
Author(s):  
L. Gimeno ◽  
M. Vázquez ◽  
R. Nieto ◽  
R. M. Trigo
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Moisture Transport ◽  
The Arctic ◽  
Atmospheric Moisture ◽  
Ice Melting ◽  
Moisture Sources ◽  
The North ◽  
Arctic Ice ◽  
Atmospheric Moisture Transport

Abstract. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting some of the most significant changes in the Arctic region. The increasing moisture over the Arctic during the last decades is not strongly associated with the evaporation that takes place within the Arctic area itself, despite the fact that the sea ice cover is decreasing. Such an increment is consistent and is more dependent on the transport of moisture from the extratropical regions to the Arctic that has increased in recent decades and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the more objective assessment of the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyse several recent results suggesting links between moisture transport and the extent of sea ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnecting results, using new information and insights. Results reached in this study stress the connection between two climate change indicators, namely an increase in evaporation over source regions (mainly the Mediterranean Sea, the North Atlantic Ocean and the North Pacific Ocean in the paths of the global western boundary currents and their extensions) and Arctic ice melting precursors.

scholarly journals A Five-Year Record of Summer Melt on Eurasian Arctic Ice Caps

2009 ◽  
Vol 22 (1) ◽  
pp. 133-145 ◽  
Author(s):  
Martin Sharp ◽  
Libo Wang
Keyword(s):  
The Arctic ◽  
North Coast ◽  
Strongly Correlated ◽  
Sea Ice Concentration ◽  
Ice Caps ◽  
Novaya Zemlya ◽  
The North ◽  
Arctic Ice ◽  
Severnaya Zemlya ◽  
Melt Duration

Abstract Climatologies and annual anomaly patterns (2000–04) of melt season duration and dates of melt onset/freeze-up on Eurasian Arctic ice masses were derived from Quick Scatterometer (QuikSCAT) backscatter data. Severnaya Zemlya, Russia, has later melt onset, earlier freeze-up, and shorter melt seasons than Svalbard, Norway/Novaya Zemlya, Russia. In all three archipelagos 2001 was the longest melt season and 2000 was the shortest. Anomalously long (short) melt seasons on Svalbard were associated with negative (positive) sea ice concentration anomalies along the north coast in June and August. Annual mean melt duration was strongly correlated with the mean (June + August) NCEP–NCAR reanalysis 850-hPa air temperature, allowing reconstruction of melt durations for the period of 1948–2005. The 2000–04 pentad had the second or third longest mean melt duration of all pentads in the 1950–2004 epoch, while the 1950–54 pentad probably had the longest. Integration of these results with previous results from Greenland and the Canadian Arctic identifies 2002 as the longest melt season in the 2000–04 period across the Arctic as a whole, and 2001 as the shortest. Correlation of melt duration anomalies for 19 discrete regions identifies seven spatially coherent areas of the Arctic with common patterns of variability in annual melt duration.

scholarly journals Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

2021 ◽  
Author(s):  
Xiaoyi Shen ◽  
Chang-Qing Ke ◽  
Bin Cheng ◽  
Wentao Xia ◽  
Mengmeng Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Reanalysis Data ◽  
Mean Value ◽  
Ocean Model ◽  
North Coast ◽  
Average Value ◽  
The North ◽  
Wind Sea ◽  
The One

AbstractIn August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled ice-ocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978 (mean value of 1.1 m, compared to the average value of 2.8 m during 1978–2017) and the modest southerly wind caused by a positive North Atlantic Oscillation (mean value of 0.82, compared to the climatological value of −0.02) were responsible for the formation and maintenance of this polynya. The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind. Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

scholarly journals Correlation and trend studies of the sea-ice cover and surface temperatures in the Arctic

2002 ◽  
Vol 34 ◽  
pp. 420-428 ◽  
Author(s):  
Josefino C. Comiso
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Ice Cover ◽  
The Arctic ◽  
Temperature Anomalies ◽  
Ice Concentration ◽  
Arctic Ice ◽  
Highly Correlated ◽  
Surface Ice ◽  
Perennial Ice

AbstractCo-registered and continuous satellite data of sea-ice concentrations and surface ice temperatures from 1981 to 2000 are analyzed to evaluate relationships between these two critical climate parameters and what they reveal in tandem about the changing Arctic environment. During the 19 year period, the Arctic ice extent and actual ice area are shown to be declining at a rate of –2.0±0.3% dec –1 and 3.1 ±0.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.4 ±0.2 K dec–1, where dec is decade. The extent and area of the perennial ice cover, estimated from summer minimum values, have been declining at a much faster rate of –6.7±2.4% dec–1 and –8.3±2.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.9 ±0.6K dec–1. This unusual rate of decline is accompanied by a very variable summer ice cover in the 1990s compared to the 1980s, suggesting increases in the fraction of the relatively thin second-year, and hence a thinning in the perennial, ice cover during the last two decades. Yearly anomaly maps show that the ice-concentration anomalies are predominantly positive in the 1980s and negative in the 1990s, while surface temperature anomalies were mainly negative in the 1980s and positive in the 1990s. The yearly ice-concentration and surface temperature anomalies are highly correlated, indicating a strong link especially in the seasonal region and around the periphery of the perennial ice cover. The surface temperature anomalies also reveal the spatial scope of each warming (or cooling) phenomenon that usually extends beyond the boundaries of the sea-ice cover.

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