Sentences with phrase «balance of the ice sheets»

Because ice sheets contain so much ice and have the potential to raise or lower global sea level so dramatically, measuring the mass balance of the ice sheets and tracking any mass balance changes and their causes is very important for forecasting sea level rise.

In 2007, Denmark launched the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) to assess changes in the mass balance of the ice sheet.

The mass balance of the ice sheets continues to change over time.

The papers do not address the total mass balance of the ice sheets, and the authors admit that the ablation at the edges may offset the gains on the interior.

RealClimate has reviewed the issues raised by these articles and attempted to clarify the sometimes conflicting inferences about the current mass balance of the ice sheets, as well as their future contributions to global mean sea level rise (see here and here).

Not exact matches

Understanding sea level change in relation to the mass balance of Greenland's and Antarctica's ice sheets is at the heart of the CReSIS mission.

One way to assess the health of ice sheets is to look at their balance: when an ice sheet is in balance, the ice gained through snowfall equals the ice lost through melting and iceberg calving.

When the team looked at the overall balance between the radiation upward from the surface of the ice sheet and the radiation both upward and downward from the upper levels of the atmosphere across all infrared wavelengths over the course of a year, they found that in central Antarctica the surface and lower atmosphere, against expectation, actually lose more energy to space if the air contains greenhouse gases, the researchers report online and in a forthcoming Geophysical Research Letters.

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.

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 unstabIce Sheet retreated rapidly at the end of the last ice age as it balanced precariously on sloping ground and became unstabice age as it balanced precariously on sloping ground and became unstable.

«What we found was that during most of the deglaciation, the surface mass balance of the Laurentide Ice Sheet was generally positive,» Ullman said.

David Ullman, a postdoctoral researcher at Oregon State University and lead author on the study, said there are two mechanisms through which ice sheets diminish — dynamically, from the jettisoning of icebergs at the fringes, or by a negative «surface mass balance,» which compares the amount of snow accumulation relative to melting.

Subtracting one from the other produced a «mass - balance» picture of net ice loss or growth for each ice sheet.

The relevant papers are [Velicogna and Wahr 2006 Measurements of time - variable gravity show mass loss in Antarctica Science 311, 1754 - 1756 and Rignot and Thomas «Mass balance of polar ice sheets» Science 297, 1502 - 1506]

A pair of satellites (GRACE) were launched several years ago to determine mass balance in the Antarctic and Greenland ice sheets.

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..

Mitrovica, J. X., Tamisiea, M. E., Davis, J. L. & Milne, G. A. Recent mass balance of polar ice sheets inferred from patterns of global sea - level change.

Ice shelves are important, because they play a role in the stability of the Antarctic Ice Sheet and the ice sheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulatiIce shelves are important, because they play a role in the stability of the Antarctic Ice Sheet and the ice sheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulatiIce Sheet and the ice sheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulaSheet and the ice sheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulatiice sheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulasheet's mass balance, and are important for ocean stratification and bottom water formation; this helps drive the world's thermohaline circulation.

That estimate was based in part on the fact that sea level is now rising 3.2 mm / yr (3.2 m / millennium)[57], an order of magnitude faster than the rate during the prior several thousand years, with rapid change of ice sheet mass balance over the past few decades [23] and Greenland and Antarctica now losing mass at accelerating rates [23]--[24].

Isabella Velicogna can use that information to «study the mass balance of the Greenland and Antarctic Ice Sheets and glaciers worldwide, in response to climate warming.»

Seeking to now provide «a little bit of balance to this concept of unstoppable retreat» of the Antarctic ice sheet, Rignot clings to hope the global community can «actually, possibly, prevent some of the big ice sheets» from inevitably melting.

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.

The mass - balance of the whole greenland ice - sheet was estimated to be the following:

While methane is short - lived, all it has to do is shift the global energy balance for a while, to trigger irreversible loss of tundra methane, loss of Arctic sea ice cover and more calthrate loss, then loss of ice sheets and everything else Hansen et al promise.

Because the drains out of the various bathtubs involved in the climate — atmospheric concentrations, the heat balance of the surface and oceans, ice sheet accumulations, and thermal expansion of the oceans — are small and slow, the emissions we generate in the next few decades will lead to changes that, on any time scale we can contemplate, are irreversible.

[Response: Rain on the flanks is not that uncommon, but enough rain on the bulk of the ice sheet to affect the surface mass balance as much as you suggest is not on.

The relevant papers are [Velicogna and Wahr 2006 Measurements of time - variable gravity show mass loss in Antarctica Science 311, 1754 - 1756 and Rignot and Thomas «Mass balance of polar ice sheets» Science 297, 1502 - 1506]

A pair of satellites (GRACE) were launched several years ago to determine mass balance in the Antarctic and Greenland ice sheets.

We have joined forces with the Greenland expert Jason Box who has reconstructed the mass balance of the Greenland ice sheet since 1840 (Fig. 6 of our paper, see also his blog).

If a negative surface mass balance were sustained for millennia, that would lead to virtually complete elimination of the Greenland ice sheet and a resulting contribution to sea level rise of about 7 m.

One has to delve deeply into the appendix of Chapter 11 of the TAR to find out what these extra 18 cm entail: they include a «mass balance uncertainty» and an «ice dynamic uncertainty», where the latter is simply assumed to be 10 % of the total computed mass loss of the Greenland ice sheet.

Shepherd et al. (2012) estimate the mass balance of the entire Antarctic Ice Sheet to be -81 ± 37 gigatonnes per year.

The findings reinforce suggestions that strong positive ice — temperature feedbacks have emerged in the Arctic15, increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice - sheet mass balance and human activities in the Arctic...» *** This is the heart of polar amplification and has very little to do with your stated defintion of amplifying the effects of warming going on at lower latitudes.

Postscript: A grouping of 40 + scientists, including four of our Nature co-authors, participated in the NASA / ESA Ice Sheet Mass Balance Intercomparison project (IMBIE) in an attempt to understand the reasons for previously disparate ice mass change estimatIce Sheet Mass Balance Intercomparison project (IMBIE) in an attempt to understand the reasons for previously disparate ice mass change estimatice mass change estimates.

The software developed will combine individual assessments of ice sheet mass balance to determine a reconciled estimate of ice sheet mass balance, taking into account the spatial and temporal domain of the input data and their uncertainties, and generate summary graphical and tabulated output.

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.

Then in 2003 the launch of two new satellites, ICESat and GRACE, led to vast improvements in one of the methods for mass balance determination, volume change, and introduced the ability to conduct gravimetric measurements of ice sheet mass over time.

At the beginning of the 1990s, scientists were unsure of the sign (positive or negative) of the mass balance of Greenland or Antarctica, and knew only that it could not be changing rapidly relative to the size of the ice sheet.

The West Antarctic Ice Sheet (WAIS) is out of balance because it is losing significant amounts of ice to the ocean, with the losses not being offset by snowfaIce Sheet (WAIS) is out of balance because it is losing significant amounts of ice to the ocean, with the losses not being offset by snowfaice to the ocean, with the losses not being offset by snowfall.

A key area of glaciological study in recent years is ice sheet mass balance.

The Greenland Ice Sheet ice properties are not changing, it is the balance of forces that is changing due to thinniIce Sheet ice properties are not changing, it is the balance of forces that is changing due to thinniice properties are not changing, it is the balance of forces that is changing due to thinning.

The impacts of ice shelf collapse and ensuing glacier acceleration are substantial, but in general, the effects of ocean melt are proving to be far more important in controlling ice sheet mass balance.

Because Antarctica drains more than 80 percent of its ice sheet through floating ice shelves, accelerated glacier flow has the potential to affect ice sheet mass balance dramatically and raise sea level (Pritchard et al. 2012).

So the 2016 - 2017 Surface Mass Balance of approximately 550 Gt yr ^ -1 may seem to have caused a positive ice sheet mass balancBalance of approximately 550 Gt yr ^ -1 may seem to have caused a positive ice sheet mass balancebalance (MB).

Given enough time, a negative net mass balance will ultimately lead to complete melting of the ice sheet, and several studies have attempted to quantify the climatic threshold and time period required for this to happen.

«A high - resolution record of Greenland mass balance» «Antarctica, Greenland and Gulf of Alaska land - ice evolution from an iterated GRACE global mascon solution» «Greenland and Antarctica ice sheet mass changes and effects on global sea level»

DMI says, The surface mass balance is calculated over a year from September 1st to August 31st (the end of the melt season) For the 2016 - 17 SMB year, which ended yesterday, the ice sheet had gained 544bn tonnes of ice, compared to an average for 1981 - 2010 of 368bn tonnes.

This is in this: The Cryosphere Estimation of the Greenland ice sheet surface mass balance for the 20th and 21st centuries X. Fettweis1, E. Hanna2, H. Gall» ee3, P. Huybrechts4, and M. Erpicum1

The magnitude and importance of snowfall on ice sheet mass balance is illustrated by the story of Glacier Girl.

The principal processes affecting the mass balance and dynamics of the ice sheets are ice mass input from snowfall with losses from sublimation and drifting.