Sentences with phrase «of ice sheet»

How much heat is the onshore wind delivering to the lower flanks of the ice sheet?

Finally, if a zero melt day anomaly were to reflect ice - free conditions, as you suggest then, much of the southern and eastern portion of the ice sheet (blue - green areas in figure 1) would actually be exposed bedrock.

And it is inspiring to see such progress being made in the detail with which models of ice sheet dynamics and other forms of change can be applied to the moderately far future.

The Greenland Ice Sheet has an area of 1,736,095 km2 according to the USGS, the density of an ice sheet is about 900 kg / cubic meter.

So, while the specific size of the ice sheet was different, the overall conditions are degraded in ways not likely to have existed in the past all at the same time.

The caves in the limestone gorge of Creswell Crags have provided archaeologists with important evidence of human activity towards the end of the last Ice Age when the area was right at the edge of the ice sheet.

New discoveries about the demise of the ice sheet that covered Western Canada at the end of the last ice age offer a preview of what we can expect as

Pitfalls in radar diagnosis of ice sheet bed conditions: lessons from englacial attenuation models

These simulations were subsequently used as forcing of an ice sheet model.

While the rest of the ice sheet isn't going to disappear overnight, it's fate is intimately tied to the fate of

However, we do not know the functional form of ice sheet response to a large persistent climate forcing.

«Simply put, the shape of the ice sheet and the contact with the ocean makes it likely that these areas respond more pronouncedly to changes in climate boundary conditions — be they atmospheric, oceanic or glaciological.»

Slow feedbacks, such as change of ice sheet area and climate - driven changes of greenhouse gases, are not included.

Numerical computer modelling of the glacier for these different time periods will help us understand whether this part of the ice sheet is susceptible to rising sea level, warming oceans or increased atmospheric temperatures.

That included a moment in July of that year when in just a few days, the vast majority of the ice sheet's surface became awash in at least some surface water, captured in this now iconic image from NASA:

Previous research by Box using ice cores — long cylinders drilled out of the ice sheet that let scientists sample hundreds of years of ice layers — showed that in the past, snowfall has increased over the ice sheet as temperatures have risen.

First, most climate simulations, including ours above and those of IPCC [1], do not include slow feedbacks such as reduction of ice sheet size with global warming or release of greenhouse gases from thawing tundra.

The Danish Meteorological Institute reported that although it's only April, nearly 12 percent of the ice sheet's surface is covered with a layer of meltwater of a depth of at least a millimeter.

While the rest of the ice sheet isn't going to disappear overnight, it's fate is intimately tied to the fate of communities along the coast.

That estimate was based in part on the fact that sea level is now rising 3.2 mm / yr (3.2 m / millennium)[57], an order of magnitude faster than the rate during the prior several thousand years, with rapid change of ice sheet mass balance over the past few decades [23] and Greenland and Antarctica now losing mass at accelerating rates [23]--[24].

«An outstanding question has been whether or not the environment at the base of the ice sheet is actually suitable for microbial life to persist,» explains Brent Christner, a microbiologist at Louisiana State University in Baton Rouge.

Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat.

«Most ice cores are collected from the middle of the ice sheet where it rarely ever melts, or on the ice sheet edge where the meltwater flows into the ocean,» Karina Graeter, the lead author of the study as a graduate student in Dartmouth's Department of Earth Sciences, said in a statement.

At least this one driver of ice sheet instability isn't operative.

This feedback could potentially result in the rapid loss of parts of the ice sheet, as grounding lines retreat along troughs and basins that deepen towards the ice sheet's interior.

I think it's simple enough to understand: ice is mobile so the surface or interior temperature of most of the ice sheet doesn't affect the ultimate result.

But in July 2012, a combination of soot from fires in Siberia coupled with warm temperatures caused a record - setting 95 percent of the ice sheet to melt over the course of a week.

Some previous theories have attributed this darkening to water on top of the ice sheet — often seen

Especially in West Antarctica, where much of the ice sheet sits below sea level, complex interactions at the edge of the ice sheet can sensitively affect the rate of ice - sheet retreat.

Matthias Kuhle's geological theory of Ice Age development was suggested by the possible existence of an ice sheet covering the Tibetan plateau during the Ice Ages.

are now thought of as inaccurate because the lower layers of the ice sheet have become buckled and jumbled up However, at least one major cold and dry event during the Eemian seems to be corroborated by the terrestrial pollen record from Europe and China (Zhisheng & Porter 1997).

The base of the ice sheet is buried beneath kilometres of ice, so measuring it in great detail is almost impossible.

In The Physical Basis of Ice Sheet Modelling, pp. 81 - 91.

As well as using a model to predict the future, we can also use it to reconstruct ice sheets in the past, giving clues as to the behaviour of the ice sheet in different climate settings.

Armed with aerial photos that reveal these trimlines, the researchers mapped the past and present sizes of the ice sheet in a 3D computer model.

Polar amplification, in which temperatures at the poles rise more rapidly than temperatures at the equator (due to factors like the global atmospheric and oceanic circulation of heat from the equator to the poles), plays a major role in the rate of ice sheet retreat.

170 (Symposium on Physical Basis of Ice Sheet Modelling, Vancouver), p. 313 - 322, 1987.

Measurements of ice sheet elevation changes indicate the volume of ice lost, and hence the contribution to sea levels, he tells Carbon Brief.

The majority of this ice loss — between 52 % and 83 % — originates from southeastern and northwestern regions of the ice sheet, says lead author

However, the Antarctic Ice Sheet is a complex system with interactions between the ice and climate, the ocean, and conditions at the base of the ice sheet.

So researchers need to look elsewhere for clues of ice sheet melt in the more distant past.

Either the glaciers would have to flow into the ocean at unrealistic rates, or rapid melting would have to be triggered over a much larger area of the ice sheet than current evidence suggests.

His comments are based on the paper «Limits in detecting acceleration of ice sheet mass loss due to climate variability», B. Wouters, J. L. Bamber, M. R. van den Broeke, J. T. M. Lenaerts and I. Sasgen, Nature Geoscience 6, 613 — 616 (2013) doi: 10.1038 / ngeo1874 Find the abstract and illustrations for that paper here.

A group of scientists has used a trove of historic aerial photos of the periphery of the ice sheet to estimate how much ice it lost over the course of the 20th century, before detailed satellite observations became available.

The information from the study helps improve scientists» understanding of the behavior of the ice sheet and what processes control the loss of ice, Beata Csatho, a geophysicist at the University of Buffalo in New York who was not involved with the work, said in a commentary published in the same issue of Nature.

When scientists talk about the «collapse» of an ice sheet, they mean irreversible, rapidly increased rates of recession.

Those elevations effectively helped them morph two - dimensional photos into a three - dimensional picture of the ice sheet at different points in time.

And on July 11 - 12 last year, gusts of warm air caused melting on virtually the entire surface of the ice sheet.

Instead, its bottommost layer, just above Lake Vostok, is lake water frozen onto the underside of the ice sheet.

For example, there appears to be a greater rate of ice sheet thinning in parts of West Antarctica and Greenland than was known about in 2001.