Sentences with phrase «surface of the ice sheet»

The major melting across the whole surface of the ice sheet in the record warm summer of 2012 caused enough water to drain down that the ice surface went «rocketing up» as much as 40 centimeters per day, study co-author Robin Bell, a climate researcher at Columbia University's Lamont - Doherty Earth Observatory, said.

The research team found the evidence confirming the stability of the East Antarctic ice sheet at an altitude of 6,200 feet, about 400 miles from the South Pole at the edge of what's called the polar plateau, a flat, high surface of the ice sheet covering much of East Antarctica.

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

We conclude that (i) the interior surface of the ice sheet can be efficiently drained under optimal conditions, (ii) that digital elevation models alone can not fully describe supraglacial drainage and its connection to subglacial systems, and (iii) that predicting outflow from climate models alone, without recognition of subglacial processes, may overestimate true meltwater export from the ice sheet to the ocean.

Unseasonably warm summers appear to be abetted by microbes and algae that grow on the increasingly wet surface of the ice sheet, producing pigments that boost the ice's absorption of solar energy.

When the team looked at the overall balance between the radiation upward from the surface of the ice sheet and the radiation both upward and downward from the upper levels of the atmosphere across all infrared wavelengths over the course of a year, they found that in central Antarctica the surface and lower atmosphere, against expectation, actually lose more energy to space if the air contains greenhouse gases, the researchers report online and in a forthcoming Geophysical Research Letters.

The topsy - turvy temperature trend stems, in part, from the region's high elevation; much of the surface of the ice sheet smothering East Antarctica lies above an elevation of 3000 meters, so it is much colder than it would be at lower altitudes.

Co-author Professor Jonathan Bamber, based at the University of Bristol, and President of the European Geoscience Union (EGU), added: «We are seeing changes in the large - scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet.

For decades, most studies on Greenland microbiology focused on cryoconite holes, small pits on the surface of the ice sheet that are filled with dark organic matter and ice - adapted algae.

They found that in northwest Greenland, cold and fresh water flowing into glacial fjords from the melting surface of the ice sheet is cooling the warmer subsurface water, which circulates clockwise around the island.

It can house more than 100 people above ground at a time, while fuel and cargo storage, waste - management facilities, maintenance garages and a power plant are all located beneath the surface of the ice sheet.

But the bottoms - up ice formation could make finding that old ice harder, since the new layer of ice scrambles the older layers of ice above it, or it could make it easier, because the older ice will be closer to the surface of the ice sheet.

What is new, experts said, is the idea that water at the ice sheet's base refreezes in huge amounts that can reshape the surface of the ice sheet.

As snow falls and settles on the surface of an ice sheet, it is compacted by the weight of new snow falling on top of it and is transformed into solid glacier ice over thousands of years.

Editor Janet Raloff, freshly back from Antarctica, scooped other science magazines with this story of living cells discovered in Lake Whillans, which sits 800 meters below the surface of an ice sheet -LRB-

What scientists once thought was a fairly simple linear process — that is, a certain amount at the surface of an ice sheet melts each year, depending on the temperature — is now seen to be much more complicated.

The black carbon would darken the surface of the ice sheet, attracting and absorbing more of the sun's heat.

According to NOAA's 2012 Arctic Report Card, the duration of melting at the surface of the ice sheet in summer 2012 was the longest since satellite observations began in 1979, and the total amount of summer melting was nearly double the previous record, set in 2010 (satellite records of melting go back to 1979.)

The scientist sums up the state of knowledge: «We used to think that it would take 10,000 years for melting at the surface of an ice sheet to penetrate down to the bottom.

Satellites that constantly scan environmental conditions on the planet's surface had revealed that from 8 July to 12 July, 97 per cent of the surface of the ice sheet contained water rather than ice, whereas typically just 45 per cent of the surface area melts at this time of year.

Microbes also create a gluelike substance that helps sediment stick to the surface of ice sheets and causes it to clump together, which can also speed melting.

The processes include water from melting on the surface of the ice sheet to flow down into crevasses and widen them further.

The study's major achievement is the addition of two key ice melting processes left out of all Antarctica - wide models to this point: Meltwater ponding and crevasse formation on the surface of ice sheets — so called «hydrofracturing» — and the tendency of ice sheets that are grounded on marine bedrock to rapidly retreat.

Second, and less important but still rather spectacular, was the melting of virtually every square inch of the surface of this ice sheet over a short period of a few days during the hottest part of the summer, a phenomenon observed every few hundred years but nevertheless an ominous event considering that it happened just as the aforementioned record ice mass loss was being observed and measured.

One is the ice sheet's albedo — the fraction of incoming solar radiation that is reflected from the surface of the ice sheet.

Because meltwater is less reflective than ice, the surface of the ice sheet is already absorbing more sunlight — previous research found that the reflectivity of the Greenland ice has dropped by 6 percent in the last decade, according to an Ohio State University release on the new research.