Sentences with phrase «of glacier surface»

Even if the temperature of the boundary layer were equal to the temperature of the glacier surface, sublimation could be sustained if (as is typically the case) the relative humidity of the boundary layer were less than 100 %.

The energy available for ablation of a glacier is determined by the energy budget of the glacier surface, illustrated in the accompanying figure.

A comparison of glacier surface elevation in 1983 and 2002 identifies the average thinning in the twenty year period from the USGS aerial photography in 1983 to 2002, for the northern branch is 15 m.

We conclude by underlining that the observed variation of glacier surface and SLA changes could be explained by the increase of temperature and decrease of precipitation in recent years.

Researchers at the University of Alaska Fairbanks have been taking airborne measurements of glacier surface height using a laser altimeter, an instrument that bounces a laser off of the ice surface and measures how long it takes to return.

The longitude and latitude of each glacier is noted in degrees and minutes, the mean slope of the glacier surface, the mean altitude of the glacier, and the surface area of the glacier are also listed.

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.

The laser altimeter data were extracted for different types of glacier surfaces derived from the Landsat data and compared with the digital elevation model to obtain elevation differences over time.

Not exact matches

The study suggests that up until 1997, whenever the ice caps and glaciers melted, the runoff would be filtered through a layer of older snow called the «firn» and trickle down to the ice surface, where it would freeze again, allowing the glaciers and ice caps to grow each winter.

Ice worms: The surface of a glacier contains a willy - nilly assemblage of irregularly shaped ice grains joined together by necks of ice.

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.

Scientists have used old aerial surveys to chart surface changes in the Arctic and Antarctic, for example by studying photographs of Greenland's glaciers to document their history.

The floating platforms of ice that ring the coast are thinning, glaciers are surging toward the sea, meltwater is flowing across the surface, fast - growing moss is turning the once shimmering landscape green and a massive iceberg the size of Delaware broke off into the ocean in July of 2017.

This is a view of Microbiome swab kit containing Microbiome samples from various physical surfaces prior to being stowed in MELFI or GLACIER to achieve experiment objectives.

The analysis is based on the fact that as the world warmed following the coldest part of the last ice age 20,000 years ago, the ice deep inside the Antarctic glaciers warmed more slowly than Earth's surface, just as a frozen turkey put into a hot oven will still be cold inside even after the surface has reached oven temperature.

This allowed them to calculate the redistribution of mass on Earth's surface due to the melting of the Greenland and Antarctic ice sheets and mountain glaciers, and model the shift in Earth's axis.

This expedition landed on the southwestern confines of the Ross Sea, and, by its explorations, showed that the great ice barrier is in reality the front of an enormous ice field or glacier, mainly floating on the surface of an extended bay or sea, and fed by glaciers coming down from the elevated land on the westerly side and probably also on the eastern.

The blooming leads to a runaway effect: The more glaciers and snow fields thaw the more algae bloom which in turn results in a darkening of the surface which again accelerates melting.

The most recent study, which marks the first time that scientists have used the beryllium - 10 surface exposure dating method to chronicle the advance and retreat of Africa's glaciers, appears in the journal Geology.

The first ecological study of an entire glacier has found that microbes drastically reduce surface reflectivity and have a non-negligible impact on the amount of sunlight that is reflected into space.

Alaska is the most glaciated U.S. state, with glaciers covering about 29,000 square miles, about 5 percent of its surface.

The glacier ice found by the team, which came from a layer that began just 50 centimetres below the surface, was dated by analysing the relative abundances of isotopes of argon in a thin layer of overlying volcanic ash.

The researchers, including scientists from the University of Leeds and University College London, used satellite data to analyze changes in the surface elevation of glaciers all around the Antarctic coastline, from 2010 to 2016.

With the grains more widely distributed, more of the grains» surface area is exposed to sunlight, and the additional meltwater lets the glacier host more life.

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.

Although CryoSat - 2 is designed to measure changes in the ice sheet elevation, these can be translated into horizontal motion at the grounding line using knowledge of the glacier and sea floor geometry and the Archimedes principle of buoyancy — which relates the thickness of floating ice to the height of its surface.

The glaciers that carved Yosemite Valley left highly polished surfaces on many of the region's rock formations.

Sunlight tends to bounce off the white, reflective surfaces of glaciers and ice sheets, but the darker surfaces of dirty ground ice can absorb greater amounts of solar radiation.

The data allowed them to calculate the redistribution of mass on Earth's surface due to the melting of the Greenland and Antarctic ice sheets and mountain glaciers, and the resulting rise in sea level.

It allows scientists to measure a variety of ice behaviors at conditions that are applicable to both terrestrial glaciers and icy moon surfaces.

GPS is being used to create a detailed and comprehensive portrait of nearly all Earth's dynamic surfaces, including the zones where tectonic plates meet, the slippage along earthquake faults, and the movement of glaciers.

At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers in the Amundsen Sea Embayment.»

It is difficult to obtain fossil data from the 10 % of Earth's terrestrial surface that is covered by thick glaciers and ice sheets, and hence, knowledge of the paleoenvironments of these regions has remained limited.

Earlier this year, the Mars Odyssey spacecraft also revealed the presence of near - surface ice (ScienceNOW, 28 May), making glaciers seem even more plausible, Marston says.

«If ice caps and glaciers were to continue to crack and break into pieces, [the amount of] their surface area that is exposed to air would be significantly increased, which could lead to accelerated melting and much - reduced coverage area on the Earth,» Buehler said in a statement.

By 1900, increased emissions of soot could have triggered the loss of more than 15 m of ice from a glacier's surface; by 1930, the loss could have totaled 30 m or more — magnitudes and timing that can easily account for the Alpine glacial retreat, the scientists contend.

Understanding how layers of air insulate the surface of glaciers, for example, is vital to making accurate estimates of how fast they will melt — and sea levels will rise — as the Earth warms under its blanket of greenhouse gases.

One study in 2011 using aerial photographs concluded that many of the glaciers in Wind River lost on average 38 percent of their surface area over the latter half of the 20th century.

Another flew a kite equipped with a GoPro camera to snap images of its surface, needed to create a 3 - D model of the glacier because drones are not allowed in federal wilderness areas.

For the new study, the authors use a new technique to discover drops at the glacier's surface of up to 70 feet (20 meters) over a 20 kilometer by 40 kilometer area.

That's because the IPCC models only take into account temperature changes at the surface of glaciers, but not the rapid melting that occurs when glaciers calve and break up into the ocean, Rignot said.

Marzeion, B., A. H. Jarosch, and M. Hofer, 2012: Past and future sea - level change from the surface mass balance of glaciers.

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.

Consistent with observed changes in surface temperature, there has been an almost worldwide reduction in glacier and small ice cap (not including Antarctica and Greenland) mass and extent in the 20th century; snow cover has decreased in many regions of the Northern Hemisphere; sea ice extents have decreased in the Arctic, particularly in spring and summer (Chapter 4); the oceans are warming; and sea level is rising (Chapter 5).

The research published in Nature Communications found that in the past, when ocean temperatures around Antarctica became more layered - with a warm layer of water below a cold surface layer - ice sheets and glaciers melted much faster than when the cool and warm layers mixed more easily.

They also trap surface water, and can divert surface streams to the base of the glacier.

The Western Antarctic Peninsula has been rapidly cooling since 1999 -LRB--0.47 °C per decade), reversing the previous warming trend and leading to «a shift to surface mass gains of the peripheral glacier» (Oliva et al., 2017).

«At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten.

It is dissected by several gullies, cut into the unconsolidated sand by streams (melting from the glacier surface is encouraged by the accumulation of dark wind - blown sand, which absorbs solar radiation)[17].

A study of satellite measurements of Pine Island glacier in west Antarctica reveals the surface of the ice is now dropping at a rate of up to 16m a year.