Sentences with phrase «based glacier ice»

Not exact matches

On both Earth and Mars, rocks and debris within cold - based glaciers can be exposed as overlying ice sublimes, turning from a solid directly into a gas.

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.

Alaskan and the Canadian Arctic land - based glacier melt ranks with that of the Greenland Ice Sheet as important contributors to global sea - level rise that is already underway.

Most glaciers are wet - based: A layer of water beneath the ice makes the glacier mobile, capable of creating steep fjords and other dramatic features that we associate with glacially sculpted terrain.

Meanwhile, ocean water seeps beneath the ice shelf and washes up against the base of the glacier.

James Balog, who founded Extreme Ice Survey that uses photography and videography to document the impact of climate change on glaciers — work that was the basis of his 2012 documentary «Chasing Ice» — said his work shows how human activities are transforming Earth's systems.

But scientists increasingly attribute much of the observed grounding line retreat — particularly in West Antarctica — to the influence of warmer ocean water seeping beneath the ice shelves and lapping against the bases of glaciers, melting the ice from the bottom up.

That is because the enormous glacier, which constitutes 10 percent of the West Antarctic Ice Sheet, is thinning rapidly, allowing more and more of its land - based ice to reach the sIce Sheet, is thinning rapidly, allowing more and more of its land - based ice to reach the sice to reach the sea.

The results now published in Environmental Research Letters seem to contradict the data from a satellite mission based on other measuring methods, which indicates a slight increase in mass in the glacier ice for an almost identical period of time.

But an ice shelf is thought to act as a «cork in the bottle,» damming the flow of the land - based glacier that slowly feeds the shelf in the sea.

Moon describes the many ways researchers study glacier dynamics, from in - place measurements on the ice to satellite - based monitoring campaigns to models.

These big game hunters spread their Clovis spearpoints — long and thin with distinctive hollows carved into both sides of the base — across the United States and northern Mexico starting about 13,000 years ago, when they arrived via an ice - free corridor through glacier - covered Alaska and western Canada.

Co-author Dr Ivan Haigh, lecturer in coastal oceanography at the University of Southampton and also based at NOCS, adds: «Historical observations show a rising sea level from about 1800 as sea water warmed up and melt water from glaciers and ice fields flowed into the oceans.

He added that studies showed that melt water had been penetrating the glaciers and was acting as a lubricant between the ice and the base rock.

These glaciers typically move via basal sliding or subglacial deformation under wet (warm)- based ice in the accumulation area, but only by internal ice deformation in the colder parts.

However, if the remaining ice shelf collapses or starts losing mass more rapidly, it could effectively unplug the glaciers next to the shelf, sending land - based ice into Southern Ocean, and contributing to sea level rise.

The ocean heat content change is from this section and Levitus et al. (2005c); glaciers, ice caps and Greenland and Antarctic Ice Sheets from Chapter 4; continental heat content from Beltrami et al. (2002); atmospheric energy content based on Trenberth et al. (2001); and arctic sea ice release from Hilmer and Lemke (200ice caps and Greenland and Antarctic Ice Sheets from Chapter 4; continental heat content from Beltrami et al. (2002); atmospheric energy content based on Trenberth et al. (2001); and arctic sea ice release from Hilmer and Lemke (200Ice Sheets from Chapter 4; continental heat content from Beltrami et al. (2002); atmospheric energy content based on Trenberth et al. (2001); and arctic sea ice release from Hilmer and Lemke (200ice release from Hilmer and Lemke (2000).

They are also studying the land - based glaciers that had been connected to the ice shelf.

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.

The highlight of the day is a stop at the base of a tidewater glacier in the hopes of seeing it «calve» - shedding gigantic chunks of ice into the ocean with a thunderous crash.

I assume every glacier is different, so there's no single answer whether meltwater is successfully penetrating through cracks to the base and staying melted, and whether stresses in the ice are opening cracks further, and which glaciers have beds sloping downhill going inland

Other factors would include: — albedo shifts (both from ice > water, and from increased biological activity, and from edge melt revealing more land, and from more old dust coming to the surface...); — direct effect of CO2 on ice (the former weakens the latter); — increasing, and increasingly warm, rain fall on ice; — «stuck» weather systems bringing more and more warm tropical air ever further toward the poles; — melting of sea ice shelf increasing mobility of glaciers; — sea water getting under parts of the ice sheets where the base is below sea level; — melt water lubricating the ice sheet base; — changes in ocean currents -LRB-?)

Overall, I estimate the mass balance of the Greenland ice sheet to be about -80 + / -10 cubic km of ice per year in 2000 and -110 + / -15 cubic km of ice per year in 2004, i.e. more negative than based on partial altimetry surveys of the outlet glaciers.

However, the idea is simple, and I've talked about this much in many presentations this winter: Take the amount of ice you need to get rid of from Greenland to raise sea level 2 m in the next century, reduce it by your best estimate of the amount that would be removed by surface mass balance losses, and try to push the rest out of the aggregate cross-sectional area of Greenland's marine - based outlet glaciers.

Chris Dudley (21, 40)-- Based on some limited knowledge about glaciers and ice sheets, I am of the fairly firm opinion that nothing above 300 ppm CO2e preserves a «safe» climate, in the long run.

Land - based ice in glaciers and ice - sheets will keep contributing to sea level rise as long as melting exceeds snowfall accumulation; stopping the growth of temperature would not stop the net melting.

Outflow from the ice - dammed lake is estimated to have been 11.3 million cubic meters; the additional 17.5 million cubic meters is due to frictional melting of ice as the flood traveled in contact with the glacier, together with an input from base flow.»

Our physical patterns are based on the physics of glacier / ice sheet melt (static equioibrium fingerprints), glacial isostatic adjustment models, and an ensemble of GCMs to inform the ocean dynamic contribution.

The contribution from glaciers and ice caps (not including Greenland and Antarctica), on the other hand, is computed from a simple empirical formula linking global mean temperature to mass loss (equivalent to a rate of sea level rise), based on observed data from 1963 to 2003.

The results revealed that the world's glaciers and ice caps — defined as all land - based ice except the mighty Greenland and West Antarctic ice sheets — began to shrink far more quickly in 2001.

These values have been estimated using relatively simple climate models (one low - resolution AOGCM and several EMICs based on the best estimate of 3 °C climate sensitivity) and do not include contributions from melting ice sheets, glaciers and ice caps.

They don't take into account the possibility that pulses of warm sea - water may become more frequent in triggering ice - shelf collapses - or that glaciers may speed up along their base due to penetrating melt - waters.

We quantify sea - level commitment in the baseline case by building on Levermann et al. (10), who used physical simulations to model the SLR within a 2,000 - y envelope as the sum of the contributions of (i) ocean thermal expansion, based on six coupled climate models; (ii) mountain glacier and ice cap melting, based on surface mass balance and simplified ice dynamic models; (iii) Greenland ice sheet decay, based on a coupled regional climate model and ice sheet dynamic model; and (iv) Antarctic ice sheet decay, based on a continental - scale model parameterizing grounding line ice flux in relation to temperature.

It's an indication that ice melt from a major glacier outflow there is cooling the surface waters even as it pulls the surface heat downward and toward the glacial base.

The next year, Rignot and Mouginot published another comprehensive, high - resolution map of Greenland based in radar interferometry data from 2008 and 2009 showing that Greenland's 100 fastest glaciers drain 66 percent of the ice sheet area, and marine - terminating glaciers drain 88 percent of the ice sheet area (Rignot and Mouginot 2012).

I argued that Greenland's glaciers would soon stabilize and sea ice in the Barents Sea would soon recover based on trends in the transport of warm Atlantic water into the Arctic.

In addition to a groundwater base flow driving the current steady rise in sea level, meltwater from retreating Little Ice Age glaciers undoubtedly contributed as well.

Based on GRACE satellite gravity estimates (illustrated in the graph below on the left) and hydrographic measurements (graph on right), Greenland's lost ice has correlated best with the pulses of warm Atlantic water that entered into the Irminger Current that flows to the west around Greenland, delivering relatively warm water to the base of Greenland's marine terminating glaciers.

Once the growth of Little Ice Age glaciers stopped, and groundwater base flow was no longer offset, we would expect sea levels to rise as witnessed during the 19th and 20th centuries.

27 January 2000: The Hektoria Glacier system is stable, but increased summer melting from climate warming in the 1980s and 1990s affected the glacier system in two ways: (1) a seasonal speedup from summer melt water percolating through the glacier ice to its base, and (2) initial retreat of the Larsen Ice Shelf due to the effects of melt ponds (downstream from this imagice to its base, and (2) initial retreat of the Larsen Ice Shelf due to the effects of melt ponds (downstream from this imagIce Shelf due to the effects of melt ponds (downstream from this image).

However, that seeming paradox is consistent with a scenario in which a «base flow» from groundwater discharge would offset any transfer of waters to growing Little Ice Age glaciers.

The melt - off from the world's ice sheets, ice caps and glaciers over eight years of the past decade would have been enough to cover the United States in about 18 inches (46 centimeters) of water, according to new research based on the most - comprehensive analysis of satellite data yet.

This project brings together senior scientists from the Desert Research Institute, the University of Colorado, the University of Southern Mississippi, the University Libre de Brussels, and the University of Alaska Fairbanks to tackle these problems as a team to create transformative new approaches to analyzing ice cores from polythermal valley glaciers to create unique records of value to a broad - base of scientists and policy makers.

Ice does not conduct heat well, and a rise of a few degrees in the air would take thousands of years to affect a glacier base a mile away, where it could lubricate the flow.

Both the observations of mass balance and the estimates based on temperature changes (Table 11.4) indicate a reduction of mass of glaciers and ice caps in the recent past, giving a contribution to global - average sea level of 0.2 to 0.4 mm / yr over the last hundred years.

Nonetheless, the findings demonstrate that satellite - based measurements of Arctic sea surface salinity are reasonably accurate and successfully reflect changes due to river runoff, melting sea ice and glaciers, and ocean circulation.

Ice shelves serve as a crucial barrier to prevent land - based ice sheets as well as glaciers from melting into oceans and increasing sea leveIce shelves serve as a crucial barrier to prevent land - based ice sheets as well as glaciers from melting into oceans and increasing sea leveice sheets as well as glaciers from melting into oceans and increasing sea levels.

Our acceptance that global warming is happening is based on tens of thousands of lines of evidence: not just thermometer readings but melting ice sheets, migrating species, retreating glaciers and rising sea levels, to name just a few.

IPCC synthesis reports offer conservative projections of sea level increase based on assumptions about future behavior of ice sheets and glaciers, leading to estimates of sea level roughly following a linear upward trend mimicking that of recent decades.

However, even though the Antarctic sea ice is growing, the continent's land - based glaciers continued to melt and shrink.»