Sentences with phrase «ice reflectivity»

The effect any previous year of sea ice reflectivity or heat loss or heat gain has been lost over the previous winter, and each year's energy budget must stand alone: That sea ice was near recent all - time highs in March and April 2012 indicates that an all - time sea ice low in September can't be attributed to any particular sea ice measurement in 2011, 2010, or 1979.

The latest average Greenland ice reflectivity (69.2 %) from 13 August is at a level still below 1 standard deviation from the 2000 - 2009 10 year «climatology».

Other factors than warming that could have temporarily lowered Greenland ice reflectivity include the effect of major volcanic eruptions or wild fires.

After a weeklong delay in data availability from a 61st satellite maneuver in 13 years to makeup low earth orbit drag, we find Greenland ice reflectivity (a.k.a. albedo) returning toward higher values, evidence of fresh snowfall accumulation and accompanying lower temperatures now as the melt season approaches its end.

Not exact matches

Over hundreds or thousands of years, vast ice sheets can melt away, further decreasing the planet's reflectivity.

Using the Shallow Radar instrument aboard NASA's Mars Reconnaissance Orbiter, Holt was able to peek beneath the ice's surface for clues; in particular, the radar could pick out differences in electrical reflectivity between overlying layers, showing how the ice built up over time.

Modeling studies on geoengineering to reflect sunlight away from the Earth suggest that modifying the planet's reflectivity could slow the meltdown of the Greenland ice sheet in the short term, but not stop it entirely, and could still allow an eventual total meltdown in the next millennia or so.

«It is a very good paper which provides valuable new insights about the physical processes controlling the change in reflectivity of the Greenland ice sheet and specifically its darkening over time,» said Eric Rignot, a senior research scientist at NASA's Jet Propulsion Laboratory who studies ice sheets but was not involved with the new study.

«Greenland's ice is getting darker, increasing risk of melting: Feedback loops from melting itself are driving changes in reflectivity.»

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.

It maps the depths and reflectivity of meltwater on the ice surface and is a one - of - a-kind piece of equipment built for this very specific application.

The study's results suggest the ice sheet hasn't lost as much reflectivity as previously thought, and that black carbon and dust concentrations haven't increased significantly and are thus not responsible for darkening on the upper ice sheet.

The apparent decline is greatest around the ice sheet's edges, but it also is occurring in the high elevation interior known as the dry snow zone, where the reflectivity is effectively reset each winter by new snowfall.

This means that the average reflectivity of remaining sea ice has also declined during the study period.

The retreat of sea ice in the Arctic Ocean is diminishing Earth's albedo, or reflectivity, by an amount considerably larger than previously estimated, according to a new study that uses data from instruments that fly aboard several NASA satellites.

The fact that reflectivity decreased in areas with dark water was not surprising, but there also was a decrease in reflectivity with remaining sea ice.

It confirmed that the mean albedo, or surface reflectivity, of the Arctic ice zone in late summer declined over an almost three - decade period, between 1982 and 2009.

New «benchmark» for loss of reflectivity Another wild card is the loss of the albedo of the ice, or its surface reflectivity.

Anyone who accepts that sunlight falling on ice free waters which has less reflectivity than sunlight falling on a large ice mass covering those waters and also accepts that this reduction in albedo has a positive feedback effect, leading to further warming, can't help but opt for A or B, it seems to me.

The reflectivity suggests that Kerberos is coated with water ice, similar to the other small Plutonian moons.

Even in the absence of huge amounts of carbon dioxide as a forcing mechanism, he said, there still appear to be trigger points that, once passed, can produce rapid warming through feedbacks such as changes in sea ice and the reflectivity of the Earth's surface.

Geoengineering proposals fall into at least three broad categories: 1) managing atmospheric greenhouse gases (e.g., ocean fertilization and atmospheric carbon capture and sequestration), 2) cooling the Earth by reflecting sunlight (e.g., putting reflective particles into the atmosphere, putting mirrors in space to reflect the sun's energy, increasing surface reflectivity and altering the amount or characteristics of clouds), and 3) moderating specific impacts of global warming (e.g., efforts to limit sea level rise by increasing land storage of water, protecting ice sheets or artificially enhancing mountain glaciers).

These wildfires release soot into the atmosphere, which accelerates the rate of melting of glaciers, snow and ice it lands upon, which can lead to less reflectivity, meaning more of the sun's heat is absorbed, leading to more global warming, which leads to even more wildfires, not to mention greater sea level rise, which is already threatening coastal areas around the world.

Note that if the N hemisphere snow becomes a permanent ice pack, the extra reflectivity provides all the «amplification» needed to explain the ice core records, as forced from incident solar energy.

Generally, in this region you may have several melt re-freeze cycles, with a blanket of new fallen snow with a reflectivity in the UV range of near 90 % versus something in the area of 50 % of ice within the first foot.

[ANDY REVKIN notes: Keep in mind that surface melting of Greenland snow (and snow on sea ice) also substantially darkens the surface and reduces its reflectivity.]

«Because of its reflectivity, Arctic sea ice is a critical cooling component of the earth's climate system; its loss will mean a much hotter world,» added Mr. Pomerance.

When black carbon falls on snow and ice, it reduces reflectivity and speeds up melting.

Far more certainly there will be changes in surface reflectivity; changes in snow and ice cover, open water area, regions of desert, vegetation patterns etc..

Is it not also therefore true that the polar areas of least water vapor, where a greater temperature increase from doubling of Co-2 would have the most effect, has the least W / sq - m percentage of both incoming S - W and outgoing L - W radiation due to the incident angle of incoming Sun light, the high reflectivity of the snow and ice, and the greatly reduced outgoing L - W radiation due to this?

Is it not also therefore true that the polar areas of least water vapor, where a greater temperature increase from doubling of Co-2 would have the most effect, has the least percentage of both incoming S - W and outgoing L - W radiation due to the incident angle of incoming Sun light, the high reflectivity of the snow and ice, and the greatly reduced outgoing L - W radiation due to this?

Further, loss of large areas of ice coverage reduce albedo (reflectivity).

It would have to be something that affected the net heat balance of the earth by affecting incoming radiation (solar inputs, aerosols, clouds), the reflectivity of the earth (ice caps, land use changes) or the ability of the surface to cool (greenhouse gases).

Through years of careful experimentation, we have isolated the most effective and safe material solution for increasing the reflectivity of ice.

Ackerman, A.S., A.M. Fridlind, A. Grandlin, F. Dezitter, M. Weber, J.W. Strapp, and A. Korolev, 2015: High ice water content at low radar reflectivity near deep convection — Part 2.

As the earth's natural air conditioner, white sea ice moderates solar heating by increasing the reflectivity of Earth's surface and decreasing the amount of heat that would otherwise by absorbed by darker ice - free Arctic seas.

But with several factors combining to increase temperatures in Greenland and reduce the reflectivity of the snow and ice cover, the ice sheet is becoming less efficient at reflecting that heat energy, and as a consequence melt seasons are becoming more severe.

In a new study, Box and a team of researchers describe the decline in ice sheet reflectivity and the reasons behind it, noting that if current trends continue, the area of ice that melts during the summer season is likely to expand to cover all of Greenland for the first time in the observational record, rather than just the lower elevations at the edges of the continent, as is the case today.

Freshly fallen snow reflects up to 84 percent of incoming sunlight, but during the warm season the reflectivity declines as the ice grains within the snowpack change shape and size.

The high reflectivity of this new planetary layer, the Lucrosphere, will radically incease our planet's albedo, and so compensate for the loss of reflective Arctic sea ice that threatens to accelerate global warming.

Trend in the reflectivity of high elevation ice in Greenland, showing the record low as of June 26, 2012.

Arctic sea ice decline and its impacts within two climate GCM experiments perturbing sea ice radiation balance: LW (blue line; reducing longwave emissivity of sea ice) and SW (orange line; reducing shortwave reflectivity).

Snow has a higher reflectivity than ice — its surface roughness means that it scatters incoming light.

The cryosphere derives its importance to the climate system from a variety of effects, including its high reflectivity (albedo) for solar radiation, its low thermal conductivity, its large thermal inertia, its potential for affecting ocean circulation (through exchange of freshwater and heat) and atmospheric circulation (through topographic changes), its large potential for affecting sea level (through growth and melt of land ice), and its potential for affecting greenhouse gases (through changes in permafrost)(Chapter 4).

Another cause of reflectivity reduction is the exposure of bare ice once the snow melts.

Black carbon deposited on the Arctic snow and ice, he says, will have only a minimal effect on its reflectivity.

The former has a noteworthy cooling effect but could conceivably still blanket the ice sheet with low reflectivity soot.

The planet's reflectivity — albedo — can change if white ice is replaced by darker vegetation or water.

The feedbacks primarily determining that response are related to water vapor, ice and snow reflectivity, and clouds.1 Cloud feedbacks have the largest uncertainty.

The range of model projections for each emissions scenario is the result of the differences in the ways the models represent key factors such as water vapor, ice and snow reflectivity, and clouds, which can either dampen or amplify the initial effect of human influences on temperature.