Sentences with phrase «glacial ice sheets»

Ice ages are generally triggered by minima in high - latitude NH summer insolation, enabling winter snowfall to persist through the year and therefore accumulate to build NH glacial ice sheets.

Apparently the drillers had hit meltwater from the top of Lake Vostok that had slowly refrozen and accreted onto the bottom of the overlying glacial ice sheet.

The research shows that volcanic eruptions beneath a glacial ice sheet would have created substantial amounts of liquid water on Mars's surface around 210 million years ago.

This started with some observation of cloud — and some near real time supercomputer moisture data visualization — segue into clouds and glacial ice sheet feedbacks from a warming Arctic.

«Water is seen on part of the glacial ice sheet that covers about 80 percent of Greenland...» Oh no!

Not exact matches

Substantial reductions in the extent of Arctic sea ice since 1978 (2.7 ± 0.6 percent per decade in the annual average, 7.4 ± 2.4 percent per decade for summer), increases in permafrost temperatures and reductions in glacial extent globally and in Greenland and Antarctic ice sheets have also been observed in recent decades.

The only current ice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Amesheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Amesheet covered northern Europe and the Patagonian Ice Sheet covered southern South AmeriIce Sheet covered southern South AmeSheet covered southern South America.

Evidence of past glacial advance and retreat is also more easily observed in the Dry Valleys, providing a window into the past behavior of the vast Antarctic ice sheets and their influence on global sea levels.

The U.S. team is one of three international groups that sought to penetrate Antarctica's subglacial waters in the past month, seeking clues not only to glacial microbiology but also to ice sheet dynamics and the impact of climate change on the continent.

Such piracy was rampant as the colossal ice sheets of the Last Glacial Maximum began shrinking around 18,000 years ago.

Their results show that East Greenland has been actively scoured by glacial ice for much of the last 7.5 million years — and indicate that the ice sheet on this eastern flank of the island has not completely melted for long, if at all, in the past several million years.

Research published in the July 2 issue of Nature reveals one reason our planet didn't succumb to an enveloping ice sheet during glacial ages.

The last glacial maximum was about 18,000 years ago, when the Patagonian ice sheet expands to include about 10 meters [33 feet] of global sea level.

It was covered with glacial ice — the East Antarctic Ice Sheice — the East Antarctic Ice SheIce Sheet.

Before the corridor closed, prior to the last glacial maximum, they moved freely up and down between the ice - free regions in the north and grasslands south of the ice sheets.

«Ice age bison fossils shed light on early human migrations in North America: Study dates the first movements of bison through an ice - free corridor that opened between the ice sheets after the last glacial maximum.&raqIce age bison fossils shed light on early human migrations in North America: Study dates the first movements of bison through an ice - free corridor that opened between the ice sheets after the last glacial maximum.&raqice - free corridor that opened between the ice sheets after the last glacial maximum.&raqice sheets after the last glacial maximum.»

The international team of co-authors, led by Peter Clark of Oregon State University, generated new scenarios for temperature rise, glacial melting, sea - level rise and coastal flooding based on state - of - the - art climate and ice sheet models.

Another thing that ice core showed, as others have before, is that the great swing in temperature between glacial and interglacial periods was invariably accompanied by great swings in the amount of greenhouse gases in the atmosphere: When the greenhouse goes up, the ice sheets go down.

The sediment cores used in this study cover a period when the planet went through many climate cycles driven by variations in Earth's orbit, from extreme glacial periods such as the Last Glacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like tglacial periods such as the Last Glacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like tGlacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like today's.

During glacial periods, sea level falls as water gets locked up in the ice sheets, and in extreme cases the Bering Strait connecting the Bering Sea to the Arctic Ocean closes and becomes a land bridge.

It seems that after the climate cooled during the last glacial period, disappearing habitat inland forced brown bears toward the coasts, where they encountered polar bears shifted there by British - Irish ice sheets.

«Rather, we have evidence for a very dynamic ice sheet that grew and shrank significantly between glacial and interglacial periods.

During the Last Glacial Maximum, Canada was completely inundated by the massive Laurentide Ice Sheet.

The Laurentide Ice Sheet, the major driving force for ocean circulation during the glacials, has also disappeared.

«Studies have shown that both the Greenland and Antarctic ice sheets contributed significantly to this sea level rise above modern levels,» said Anders Carlson, an Oregon State University glacial geologist and paleoclimatologist, and co-author on the study.

«We see processes that operate in the climate system that either don't operate in glacial times we've seen in the last 2 million years, or they operate very differently,» she said, citing the behavior of ice sheets as an example.

The pressure of the ice sheet constrains the lava flow, and glacial meltwater chills the erupting lava into fragments of volcanic glass, forming mounds and ridges with steep sides and flat tops.

The beginning of the last glacial period was characterized in the Northern hemisphere by significant accumulation of snow at high latitudes and the formation of a huge polar ice sheet.

Since so much of the ice sheet is grounded underwater, rising sea levels may have the effect of lifting the sheets, allowing more - and increasingly warmer - water underneath it, leading to further bottom melting, more ice shelf disintegration, accelerated glacial flow, and further sea level rise, and so on and on, another vicious cycle.

At the end of the last glacial maximum, when ice sheets reached their maximum extent 20,000 to 25,000 years ago, the ice covering Antarctica was even thicker than it is today.

«the last glacial period is a good example of a large forcing (~ 7 W / m ^ 2 from ice sheets, greenhouse gases, dust and vegetation) giving a large temperature response (~ 5 ºC) and implying a sensitivity of about 3ºC (with substantial error bars).»

As we have discussed previously, the last glacial period is a good example of a large forcing (~ 7 W / m2 from ice sheets, greenhouse gases, dust and vegetation) giving a large temperature response (~ 5 ºC) and implying a sensitivity of about 3ºC (with substantial error bars).

«Conversely, there is more and better evidence across Iceland that when the ice sheet underwent major reduction at the end of the last glacial period, there was a large increase in both the frequency and volume of basalt erupted — with some estimates being 30 times higher than the present day.

Recent research shows that there is high microbial activity on glacial surfaces (Anesio et al., 2009), some associated with pigmented algae, which absorb significantly more light than local inorganic dust particles on the Greenland Ice Sheet (GrIS)(Lutz et al., 2014).

However, it's quite a different matter melting a long - lived massive ice sheet up to 1.5 km thick that covers over 70 % of the land surface (as happened at the end of the last glacial period), from melting isolated and much thinner ice caps / sheets that only cover about 11 % of the land surface (i.e. present - day).»

A 3 - D model for the Antarctic ice sheet: a sensitivity study on the glacial - interglacial contrast.

During the Middle Pleistocene, ice sheets were reaching the continental shelf for longer, with more distinct glacial - interglacial cyclicity [28].

Terrestrial glacial geologists (such as ourselves) can gain information of past glacial behaviour from mapping and dating former ice sheet extents, and determining the rates at which they receded and thinned, [e.g., 16, 17 - 19].

Anderson, J.B., Shipp, S.S., Lowe, A.L., Wellner, J.S., and Mosola, A.B., 2002, The Antarctic ice sheet during the last glacial maximum and its subsequent retreat history: a review, Quaternary Science Reviews.

Ice sheet models can be run through many glacial cycles (i.e. cold glacial periods and warm interglacial periods).

It is thus suggested that D / O events are a consequence of interactions of the windfield with the continental ice sheets and that better understanding of the wind field in the glacial periods is the highest priority.

Willis, M J, Wilson, T J, James, T S, Mazzotti, S, (2009), GPS Constraints on Glacial Isostatic Adjustment Models and Implications for Ice Sheet Mass Balance in West Antarctica, Eos Trans.

Willis, M J, Wilson, T J, James, T S, Mazzotti, S, Bevis, M G, Kendrick, E C, Brown, A, (2010) Geodetically - Constrained Glacial Isostatic Adjustment models of Antarctica: Implications for the Mass Balance of the West Antarctic Ice Sheet, Abstract G34A - 03 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13 - 17 Dec..

As glacial geologists, some of the biggest questions that we'd like to answer are not only how large former ice sheets were, but also how fast did the recede and how quickly did they thin?

However, as a glacial period lengthens, ice sheets become larger, but also more unstable.

Here we show that the East Greenland Ice Sheet existed over the past 7.5 million years, as indicated by beryllium and aluminum isotopes (10Be and 26Al) in quartz sand removed by deep, ongoing glacial erosion on land and deposited offshore in the marine sedimentary record.

Huybrechts, P., 2002: Sea - level changes at the LGM from ice - dynamics reconstructions of the Greenland and Antarctic ice sheets during the glacial cycles.

Since then, the world has seen cycles of glaciation with ice sheets advancing and retreating on 40,000 - and 100,000 - year time scales called glacials (glacial advance) and interglacials (glacial retreat).

Gallée, H., et al., 1991: Simulation of the last glacial cycle by a coupled, sectorally averaged climate — ice sheet model.

On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.