Sentences with phrase «calving fronts»

This is why understanding the basal slope changes inland of the calving fronts is crucial.

Even temperate ice is quite strong and can sustain massive calving fronts.

Is there a point where the mountains ringing Greenland open up such that as the calving fronts continue to retreat, they will begin to greatly widen?

Historic photos and maps (from the 1800's to present) indicate a long term retreat of ice calving fronts on Greenland's glaciers.

Unlike the great ice sheet of Antarctica, the Greenland ice sheet is melting both on its surface and also at outlet glaciers that drain the ice sheet's mass through deep fjords, where these glaciers extend out into the ocean and often terminate in dynamic calving fronts, giving up gigaton - sized icebergs at times.

In the summer of 2008, Rignot's team measured salinity, temperature and current speeds near four calving fronts in three fjords in western Greenland.

«As the glacier's calving front retreats into deeper regions, it loses ice — the ice in front that is holding back the flow — causing it to speed up,» Joughin clarifies.

At its calving front, where the glacier effectively ends as it breaks off into icebergs, some of the ice melts while the rest is pushed out, floating into the ocean.

This means that, even though the glacier is flowing towards the coast and carrying more ice into the ocean, its calving front is actually retreating.

The calving front of the glacier is now located in a deeper area of the fjord, where the underlying rock bed is about 1300 metres below sea level, which the scientists say explains the record speeds it has achieved.

The most obvious example of this is the case of calving glaciers where their gross behaviour may relate more to water depth at the calving front than small - scale climate variations.

I suppose that may have to do with in - between advancing of the glacier's calving front?

Helheim Glacier is five kilometers wide and at the calving front less than 1 km thick, from 2001 - 2005 it retreated 8 km, you are looking at less than a contribution of 40 km3 for a five kilometer retreat over a span of four years.

The most obvious example of this is the case of calving glaciers where their gross behaviour may relate more to water depth at the calving front than small - scale climate variations.

According to the NASA map, the retreat of the calving front in the period 1929 - 1953 (24 years) was as large as the retreat in the period 1953 - 2003 (50 years).

The reduced resistive force at the calving front is then propagated up glacier via longitudinal extension in what R. Thomas calls a backforce reduction (Thomas, 2003 and 2004).

Thinning causes the glacier to be more buoyant, even becoming afloat at the calving front, and is responsive to tidal changes.

There has also been an alarming increase in the number of photographs of meltwater draining into a moulin somewhere on the GIS, often near Swiss Camp (35 km inland from the calving front).

On Jakobshavn the acceleration began at the calving front and spread up - glacier 20 km in 1997 and up to 55 km inland by 2003 (Joughin et al., 2004).

Four GPS receivers monitored ice flow from 55 to 171 km inland of the calving front at the center of the glacier (Scott and others, 2009).

The glacier to the north (San Rafael) also has well - developed morianes systems and it, too, was once a piedmont lobe but now has a calving front.

Of course, the calving front will be a spectacular 30 km across the main trunk and, where Columbia has earth on each side, the PIG has ice on both sides of the channel; so, it will be more complicated than the Columbia collapse.

If the ice upstream from the calving front warms from whatever it was does that affect the flow rate of the glacier?

Change was afoot: after 50 years of apparent stability, the glacier calving front was retreating, and the grounding line was retreating indicating reduced bedrock anchoring.

That acceleration began at the calving front and spread upglacier 20 km in 1997 and up to 55 km inland by 2003 (Joughin et al., 2004).

The thinning between the grounding line and the calving front is mainly via melting as the snowline is at 900 m.

Illustrating the poor connection of the Petermann Glacier to its margin and lack of a stabilizing force this margin has, even 15 km behind the calving front.

The Petermann Glacier lost a substantial area, 29 km2 due to calving this summer (Box 2008c), and a crack well back of the calving front indicates another 150 km2 is in danger.

The calving front protrudes a mere 5 - 10 m above sea level, reflecting the fact that the ice at the front is only 60 - 70 m thick.

The measurements are some distance from the calving front and may not have resulted in warming under the floating section.

The mass balance at the calving front is the sum of the ice flux from upglacier, the rate of melting above and below the waterline and the iceberg - calving rate.

Acceleration at the calving front will then effectively pull on the ice upstream, stretching it causing further thinning and acceleration.

The reduced resistive force at the calving front due to the thinner ice, now experiencing greater flotation, is then propagated «upglacier» (Hughes, 1986; Thomas, 2003 and 2004).

Mass balance transfer to the calving front is a slow process with a large lag time (centuries) and is not capable of playing a meaningful role in the recent relatively large and sudden glacier accelerations (Pfeffer, 2007).

More often, however, as with Gotley and its 11 neighbours, the icebergs break off as soon as the ice reaches sea level, so the calving front doesn't change much.

Between November 9 — 11, 2013, a large iceberg finally separated from the calving front of Antarctica's Pine Island Glacier.

The outlet glaciers have a balance of forces at the calving front.

The small protruding glacier tongue in the lower part of the picture belongs to Glacier Pierre Curie, which now ends a kilometre from the sea but in 1963 had a calving front about 600 m wide.

If the glacier thins than there is less friction at the calving front from the fjord walls and the fjord base, leading to greater flow.

This means that, even though the glacier is flowing towards the coast and carrying more ice into the ocean, its calving front is actually retreating, stated the press release.

The thermocline adjacent in the sea adjacent to the glacier calving front (where ice is discharged) lowered by 250 meters in the austral summer of 2012.

The acceleration to worry about is from changes in the calving front, and the resultant retreat and acceleration that has been observed on almost all Greenland marine terminating outlet glaciers.

Not exact matches

Even relatively large calving events, where tabular ice chunks the size of Manhattan or bigger calve from the seaward front of the shelf, can be considered normal if the ice sheet is in overall balance.

RETREATING ICE Jakobshavn Glacier in western Greenland (its front edge, where ice is calving into the ocean, shown here in 2012) is one of the world's fastest - shrinking glaciers.

«The new branch is heading off more toward the ice front, so it's more dangerous and more likely to cause this calving event to occur» than the main branch, he says.

More specifically, using digital scans of paper maps based on aerial imagery acquired by the U.S. Geological Survey, along with modern - day satellite imagery from a variety of platforms, the authors digitized a total of 49 maps and images from which they calculated changes in the terminus positions, ice speed, calving rates and ice front advance and retreat rates from 34 glaciers in this region over the period 1955 - 2015.

Stresses from ice flowing over bedrock or around islands causes fracturing, and at the front edge of the ice this fracturing leads to iceberg calving.

In part because the large Jakobshavn Isbrae moves so quickly, it is difficult to tell the glacier ice (right and top) from the many icebergs it has calved off (center front) into the fjord.

It is through an enhanced Jakobshavn Effect (calving at the marine - terminating glacial fronts) that the mass - loss is expected to occur.

Note how the ice front has calved back several kilometers from 1992 to 2000.