Sentences with phrase «by a glacier as»

The bottom few feet of ice is probably cluttered with such debris, picked up by the glacier as it slid over the hidden face of Antarctica for thousands of years.

The friction created by a glacier as it moves must contribute.

Not exact matches

Howat and his team were able to figure this out by creating high - resolution topographic models of the glaciers and their boundaries, as well as a numerical model of exactly how much water was flowing off these coastal glaciers and ice caps — technology that wasn't available back in 1996.

But, one area the previous owner ignored was the Mitchell Zone, as it was covered by a glacier when Placer conducted its activities.

By Martin Kunz, EMEA Segment Leader, Industry with Xylem's Applied Water Systems business Only 2.5 percent of the world's water is fresh water, and of that, only one percent is accessible as much is trapped in glaciers and snowfields.

Unfortunately, however, the snow had been so unexpected that the «Stade» (the race piste that finishes opposite VarCity) had not been prepared by the resort staff, and, as a result, we were faced with a daily commute up to the glacier, where we were greeted both by our coaches and a wind chill of -28 °C.

The panel had written that the glaciers of the Himalayas could vanish by 2035 but in January retracted the statement (pdf) as «poorly substantiated.»

Just over 1 % of our planet's glaciers — some 2300 in all — are known to undergo these precipitous movements, though the number is likely to rise as glaciers come under closer surveillance by remote sensing.

The broad, bright plains known as Sputnik Planum seem to be covered by nitrogen glaciers; these flow gloppily, and quickly erase craters made by crashing asteroids.

A small glacier lake known as Nagma Pokhari sits nestled in a valley near Mount Everest in Nepal, surrounded by steep walls of sediment that hold the icy waters in place.

As glaciers in most parts of the Himalayas melt, floods caused by the bursting of rapidly expanding glacial lakes pose an increasing risk to mountain communities.

He and colleagues thought that the answer to the floodwater question might also lie in the lakes» moraines — piles of sediments bulldozed by glaciers into high ridges that act as dams.

A laser altimeter onboard the ICESat satellite had documented the thinning of glaciers feeding into Larsen B and Scar Inlet — as indicated by lowering of the ice surface — but the altimeter had fizzled out earlier that year.

As glaciers disappear in the rain shadow of the Himalayas, one man is helping farmers irrigate their fields by storing water in an innovative way

Today, as warming waters caused by climate change flow underneath the floating ice shelves in Pine Island Bay, the Antarctic Ice Sheet is once again at risk of losing mass from rapidly retreating glaciers.

Thousands of marks on the Antarctic seafloor, caused by icebergs which broke free from glaciers more than ten thousand years ago, show how part of the Antarctic Ice Sheet retreated rapidly at the end of the last ice age as it balanced precariously on sloping ground and became unstable.

As the glacier passes by outside the airplane window, she notes that Thwaites could take perhaps 200 years or more to collapse.

The finding suggests that bryophytes are more resilient than was previously known, the authors say, and likely play a role in the early recolonization of areas revealed by glacier melt, such as those in the Canadian and Alaskan Arctic.

The research showed that, compared to pure snow and ice, the reflectivity of the glacier (known as the «albedo») can be reduced by up to 80 % in places where coloured microbial populations are extremely dense, leading to the darkening of the glacier surface.

All these cooking fires are, in effect, drying the region, both by contributing to the melting of glaciers that feed Asia's major rivers as well as by decreasing the evaporation that drives rainfall.

SPEED UP The collapse of West Antarctica's glaciers may be unavoidable, and the ice sheet's demise could raise global sea level by as much as 4 meters, researchers reported.

While some may see evidence of rapid glacier thinning in the past and again today as evidence that the West Antarctic Ice Sheet is nearing a collapse driven by human - caused climate change, Steig said at this point, scientists just don't know whether that is the case.

He recently took that experience to Nepal, where he collected water samples from the Himalayan glacier - fed Kosi River as part of an expedition led by the Mountain Institute.

All told, if the eastern and western Antarctic ice shelves were to melt completely, they would raise sea levels by as much as 230 feet (70 meters); the collapse of smaller shelves like Larsen B has sped up the flow of glaciers behind them into the sea, contributing to the creeping up of high tide levels around the world.

They observed three types of ice losses, each with a distinctive and detailed sound signature: the splash of an ice block falling off into the water; the crack of a fragment sliding down the glacier's rough surface; and the soft thud of an underwater ice chunk breaking away and floating up, followed by a secondary impact as it surfaces.

When the glacier starts to retreat, the frontal moraines are no longer protected by the ice, and a sort of «geological chronometer» is triggered, as the rocks begin to accumulate beryllium - 10 and helium - 3 produced by particles resulting from cosmic rays.

This is because the campaign's seafloor survey revealed features under the ocean, such as troughs cut by glaciers during the last ice age, which must continue upstream under the glacial ice.

To ascertain the age of the boulders strewn by the glaciers and thus come up with a date when glaciers were at their greatest extent, Willenbring and colleagues used a technique known as cosmogenic nuclide exposure dating, which measures the chemical residue of supernova explosions.

Totten Glacier, the largest glacier in East Antarctica, is being melted from below by warm water that reaches the ice when winds over the ocean are strong — a cause for concern because the glacier holds more than 11 feet of sea level rise and acts as a plug that helps lock in the ice of the East Antarctic Ice Sheet.

Even China's efforts to combat those rising concentrations — in part by switching from burning coal to capturing the power latent in rivers like the Yangtze — falter in the face of global warming, as a result of less water in those rivers due to drought and the dwindling glaciers of the Tibetan Plateau.

Thus, while England's native flora was largely scraped away by glaciers, in the Hengduans a variety of plants flourished — including angiosperms, such as the Magnoliaceae and Ranunculaceae, which originated in the Cretaceous Period.

Glaciers contribute a relatively small amount of water by comparison, but they do play a stabilizing role by serving as a savings bank of sorts for the state's water needs.

As glaciers recede, they leave behind lakes typically dammed by bedrock or glacial debris.

Within a single day, as a crack in the glacier shortened, the researchers discovered that the spectral peak produced by water passing through that crack rose from 120 hertz to a frequency of about 180 hertz.

Additional precision in this study was provided by NASA's Gravity Recovery and Climate Experiment, or GRACE satellites, which can make detailed measurements of gravity and, as one result, estimate the mass of glaciers they are flying over.

After that heyday, the bears must have been split up into small, isolated populations — genetic bottlenecks — perhaps as they sought refuge on islands and other areas not covered by advancing glaciers during the most recent ice age.

This remarkable correlation is supported by observations by other scientific teams who had already observed traces of glacier melting and retreat, as well as evidence of subsurface ice, in the former polar regions.

Professor Poinar continues, «Mammoths were much better at adapting to new habitats than we first thought — we suspect that subgroups of mammoths evolved to deal with local conditions, but maintained genetic continuity by encountering and potentially interbreeding with each other where their two different habitats met, such as at the edge of glaciers and ice sheets.»

As the climate continued to change, not enough snow fell to maintain the glaciers, and the holes left by the glaciers could have caught windblown snow and preserved it in drifts.

On the other hand, if the ice shell is sufficiently thick, the less intense interior heat can be transferred to warmer ice at the bottom of the shell, with additional heat generated by tidal flexing of the warmer ice which can slowly rise and flow as do glaciers do on Earth; this slow but steady motion may also disrupt the extremely cold, brittle ice at the surface to produce the chaos regions.

The valleys and ridges that were etched into Buzzards Bay's coastlines by the expansion and retreat of glaciers manifest as a string of small bays around the edges of a greater one.

While the Alps could lose anything between 75 percent and 90 percent of their glacial ice by the end of the century, Greenland's glaciers — which have the potential to raise global sea levels by up to 20 feet — are expected to melt faster as their exposure to warm ocean water increases.

(This makes it clear why glaciers in coastal Norway are not as strongly influenced by temperature — at these locations, winter precipitation typically exceeds several ice - equivalent meters per year).

Many scientists concede that without drastic emissions reductions by 2020, we are on the path toward a 4C rise as early as mid-century, with catastrophic consequences, including the loss of the world's coral reefs; the disappearance of major mountain glaciers; the total loss of the Arctic summer sea - ice, most of the Greenland ice - sheet and the break - up of West Antarctica; acidification and overheating of the oceans; the collapse of the Amazon rainforest; and the loss of Arctic permafrost; to name just a few.

Ice - Capped Roof of World Turns to Desert Scientists warn of ecological catastrophe across Asia as glaciers melt and continent's great rivers dry up by Geoffrey Lean May 7, 2006 The Independent / UK

Estimates from the study indicate that the freezing line could lift by as much as 3,900 feet by 2100, which could expose the majority of glaciers in the region to temperatures above 32 °F in warm - weather months.

Ice shelf collapse and glacier recession here, in front of the large ice streams such as Pine Island Glacier and Thwaites Glacier, would have potential to raise sea levels by tens of centimetres to a metre, through the process of marine ice sheet instability23.

«As glaciologists and glacial geologists, we respond to the article «Glaciers — science and nonsense» by Cliff Ollier in the March issue of Geoscientist1.

Under warming conditions glaciers may contribute as much as more than half a meter by 2100.»

Perhaps worldwide melting of glaciers by global warming will increase the incidence of volcanic eruptions and earthquakes, as well as increasing the intensity of hurricanes.