A Possible Explanation of Differences Between Pre- and Post-Jaramillo Ice Sheet Growth

AbstractThe pattern of horizontal strain rate in an ice sheet is discussed from a topological point of view. In a circularly symmetric ice sheet, the isotropic point for strain rate at its centre is degenerate and structurally unstable. On perturbation the degenerate point splits into two elementary isotropic points, each of which has the lemon pattern for the trajectories of principal strain rate. Contour maps of principal strain-rate values are presented which show the details of the splitting.

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Satellite Altimeter Results Over East Antarctica

Annals of Glaciology ◽

10.3189/s0260305500002482 ◽

1982 ◽

Vol 3 ◽

pp. 32-35 ◽

Cited By ~ 2

Author(s):

R. L. Brooks

Keyword(s):

Tracking System ◽

Ice Sheet ◽

East Antarctica ◽

Satellite Altimeter ◽

Ice Shelves ◽

Ice Surface ◽

Operational Lifetime ◽

Waveform Retracking ◽

Better Than

During the operational lifetime of the Seasat altimeter from 3 July to 10 October 1978, more than 450 overflights were made over East Antarctica inland to latitude 72°S. An analysis of selected passes over a variety of ice features demonstrates that the oceanographic altimeter performed surprisingly well over the ice sheet and ice shelves, acquiring useful measurements during approximately 70% of each pass. The altimeter's onboard tracking system dampened out the ice-surface elevations, but post-flight retracking of the stored return waveforms reveals excellent ice-surface details. After waveform retracking, the altimeter repeatability is better than ±1 m.

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Analysis and Simulation of Altimeter Performance for the Production of Ice Sheet Topographic Maps

Annals of Glaciology ◽

10.3189/s0260305500001324 ◽

1986 ◽

Vol 8 ◽

pp. 141-145 ◽

Cited By ~ 1

Author(s):

K.C. Partington ◽

C.G. Rapley

Keyword(s):

High Precision ◽

Systems Analysis ◽

Ice Sheets ◽

Ice Sheet ◽

Data Interpretation ◽

Topographic Maps ◽

Error Signal ◽

Tracking Systems ◽

Tracking Mode ◽

Non Linear

Satellite-borne, radar altimeters have already demonstrated an ability to produce high-precision, topographic maps of the ice sheets. Seasat operated in a tracking mode, designed for use over oceans, but successfully tracked much of the flatter regions of the ice sheet to ± 72° latitude. ERS-1 will extend coverage to ± 82° latitude and will be equipped with an ocean mode similar to that of Seasat and an ice mode designed to permit tracking of the steeper, peripheral regions. The ocean mode will be used over the flatter regions, because of its greater precision.Altimeter performance over the ice sheets has been investigated through a study of Seasat tracking behaviour and the use of an altimeter performance simulator, with a view to assessing the likely performance of ERS-1 and the design of improved tracking systems. Analysis of Seasat data shows that lock was frequently lost, as a result of possessing a non-linear height error signal over the width of the range window. Having lost lock, the tracker frequently failed to transfer rapidly and effectively to track mode. Use of the altimeter performance simulator confirms many of the findings from Seasat data and it is being used to facilitate data interpretation and mapping, through the modelling of waveform sequence.

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Rapid and rhythmic ice sheet fluctuations in western Scandinavia 15-40 Kya–a review

Polar Research ◽

10.3402/polar.v21i2.6483 ◽

2002 ◽

Vol 21 (2) ◽

pp. 235-242 ◽

Cited By ~ 2

Author(s):

Lars Olsen ◽

Harald Sveian ◽

Klaas van der Borg ◽

Bjørn Bergstram ◽

Maarten Broekmans

Keyword(s):

Ice Sheet

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The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/ggub.v176.5073 ◽

1997 ◽

pp. 95-103 ◽

Cited By ~ 5

Author(s):

Henrik Højmark Thomsen ◽

Niels Reeh ◽

Ole B. Olesen ◽

Carl Egede Bøggilde ◽

Wolfgang Starzer ◽

...

Keyword(s):

Climatic Change ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

East Greenland ◽

Changing Climate ◽

North East ◽

Integrated Research ◽

Research Themes ◽

Advance Research ◽

Inland Ice

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Højmark Thomsen, H., Reeh, N., Olesen, O. B., Egede Bøggilde, C., Starzer, W., Weidick, A., & Higgins, A. K. (1997). The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change. Geology of Greenland Survey Bulletin, 176, 95-103. https://doi.org/10.34194/ggub.v176.5073 _______________ Glaciological research was initiated in 1996 on the floating glacier tongue filling Nioghalvfjerdsfjorden in NorthEast Greenland (Fig. 1), with the aim of acquiring a better understanding of the response of the Greenland ice sheet (Inland Ice) to changing climate, and the implications for future sea level. The research is part of a three year project (1996–98) to advance research into the basic processes that contribute to changes in the ocean volume with a changing climate. Five nations are participants in the project, which is supported by the European Community (EC) Environment and Climate Programme. The Geological Survey of Denmark and Greenland (GEUS) and the Danish Polar Center are the Danish partners in the project, both with integrated research themes concentrated on and around Nioghalvfjerdsfjorden.

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Could climate engineering save the Greenland Ice Sheet?

Climanosco Research Articles - https://www.climanosco.org/collection/climate-change-and-its-impacts/ ◽

10.37207/cra.1.10 ◽

2016 ◽

Author(s):

Patrick J. Applegate ◽

K. Keller

Keyword(s):

Sea Level Rise ◽

Greenhouse Gas Emissions ◽

Greenhouse Gas ◽

Sea Level ◽

Computer Model ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Upper Atmosphere ◽

Climate Engineering ◽

Air Temperatures

Engineering the climate through albedo modification (AM) could slow, but probably would not stop, melting of the Greenland Ice Sheet. Albedo modification is a technology that could reduce surface air temperatures through putting reflective particles into the upper atmosphere. AM has never been tested, but it might reduce surface air temperatures faster and more cheaply than reducing greenhouse gas emissions. Some scientists claim that AM would also prevent or reverse sea-level rise. But, are these claims true? The Greenland Ice Sheet will melt faster at higher temperatures, adding to sea-level rise. However, it's not clear that reducing temperatures through AM will stop or reverse sea-level rise due to Greenland Ice Sheet melting. We used a computer model of the Greenland Ice Sheet to examine its contributions to future sea level rise, with and without AM. Our results show that AM would probably reduce the rate of sea-level rise from the Greenland Ice Sheet. However, sea-level rise would likely continue even with AM, and the ice sheet would not regrow quickly. Albedo modification might buy time to prepare for sea-level rise, but problems could arise if policymakers assume that AM will stop sea-level rise completely.

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