Sentences with phrase «snow reflectivity»

In a study coordinated by the Finnish Meteorological Institute, the computation of snow reflectivity for solar radiation (aka.

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.

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

A series of unique experiments organized by FMI were conducted to further study the effects of soot particles on snow reflectivity and snow melt.

In a study coordinated by the Finnish Meteorological Institute, the computation of snow reflectivity for solar radiation (aka.

Not exact matches

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.

Black carbon aerosols — particles of carbon that rise into the atmosphere when biomass, agricultural waste, and fossil fuels are burned in an incomplete way — are important for understanding climate change, as they absorb sunlight, leading to higher atmospheric temperatures, and can also coat Arctic snow with a darker layer, reducing its reflectivity and leading to increased melting.

Dartmouth Adjunct Assistant Professor Chris Polashenski and his colleagues found that degrading satellite sensors, not soot or dust, are responsible for the apparent decline in reflectivity of Arctic snow.

Two properties dominate reflectivity in dry snow — the size of snow grains, which become larger and more absorbent as they melt, and the presence of dark impurities that absorb the sun's energy, predominantly black carbon and mineral dust, which also cause the snow to melt faster.

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.

The results showed no significant change in the quantity of black carbon deposited for the past 60 years or the quantity and mineralogical makeup of dust compared to the last 12,000 years, meaning that deposition of these light absorbing impurities is not a primary cause of reflectivity reduction or surface melting in the dry snow zone.

In trying to explain the apparent decline in reflectivity, lead author Chris Polashenski, an adjunct assistant professor at Dartmouth's Thayer School of Engineering and a research geophysicist at the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory, and his colleagues analyzed dozens of snow - pit samples from the 2012 - 2014 snowfalls across northern Greenland and compared them with samples from earlier years.

Lower reflectivity would likely increase the snow's melt rate because it means more sunlight gets absorbed, though that wasn't directly shown.

But if you want to mimic the reflectivity of snow: yes.

When snow melts in response to warming, more sunlight can be absorbed at Earth's surface because most surfaces have a lower reflectivity than snow.

For U.S. farmers, changes in the snow's reflectivity could affect when the spring melt will occur and when meltwater will drain out.

The infrared findings indicated that UB313 has a reflectivity, or albedo, of about 60 percent, which is similar to Pluto's and suggested that the two bodies have surfaces are made of very similar materials such as frozen methane and nitrogen snow at a temperature of -248 °C or -418 °F.

Because a thin layer of snow is just as reflective as a thick layer, the reflectivity effect depends more on the seasonal distribution of snowfall than the annual average amount.

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.

This is a result of dynamic N hemisphere reflectivity from fallen snow.

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.]

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..

The continent is almost completely covered in snow year round so the south pole maintains its high reflectivity during the summer months.

With less summer snow falling and melting underway, northern Greenland's albedo, or reflectivity, also decreased.

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?

This prevents a long - lasting snow cover with a high reflectivity to form and protect the glacier surface.

When there's snow surrounding your panels, it creates a vibrant white surface around them, adding to your roof's reflectivity.

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.

The high reflectivity of snow is what has kept Greenland so cold by redirecting incoming heat from the sun back out toward space.

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.

Snow surfaces, on the other hand, have high reflectivity (40 — 80 percent) and so are the poorest absorbers.

As the snow gets dirtier, its reflectivity decreases, and it melts faster, which causes a positive feedback loop, said the study's lead author, Marco Tedesco, a glaciologist at Columbia University's Lamont - Doherty Earth Observatory in Palisades, N.Y.

Most of the greening was driven by the loss of reflectivity, or albedo, from snow cover.

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

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 method is based on an empirical relation between UV reflectivity and measured snow depth.

Earlier this year he and others pinpointed a change in albedo — a measure of the reflectivity of snow on the island — that suggested that melting might accelerate.

That is until the surface is covered by snow, which being about the same reflectivity as clouds, cancels the decrease in the incident power so that the net effect is to trap surface warmth.

This «simple physics» model becomes a bit more complex when we factor - in the «positive feedbacks» — changes in reflectivity as snow and ice melt; as vegetation shifts; etc..

One example: the feedback through albedo — the reflectivity of the Earth such as can be affected by snow cover.

But these snow - covered caps are increasingly interrupted by pits like these, whose black mud bottoms of rocky sediment called cryoconite drastically reduces polar surface reflectivity.

I am still not convinced that reflectivity of water at 24 degrees would be equal to that of snow and ice at the same angle.

These effects are magnified by snow and ice: by reducing snow and ice cover, warming reduces the reflectivity of the ground and allows more solar energy to be absorbed, further increasing the warming; conversely for cooling.»

«More snow means more snowmelt in [the] spring, resulting in larger melt ponds at that time,» which lowers the reflectivity of the sea ice, Feltham said.

Cook explains that the darkening is the result of a melt - induced feedback that polar scientists have long documented: Upon melting and refreezing, ice crystals lose their spiky shape and grow larger and rounder, which can reduce the reflectivity of the snow by as much as 10 %.