Sentences with phrase «albedo by»

Since the reduction of albedo by grain growth is confined to the near infrared, it is mostly invisible to our eyes.

For pure snow, grain growth from new snow (grains around 0.1 millimeter in radius) to old melting snow (radius around 1 millimeter) can reduce broadband albedo by around 10 %.

Might I suggest that everyone read the proposal by Latham, Salter et al about using atomised water sprays — more hygroscopic nuclei in deficient areas of the ocean should raise albedo by increasing stratocumulus cover in the boundary layer — to cool selected areas?

You have exaggerated the error ranges in the albedo by looking at the separate estimates of land and ocean albedo.

I seem to recall from a talk by Ken Caldeira this summer that one is talking about increasing the albedo by 10 % only over the region from 80 - 90 north latitude.

Clouds can also enhance the planetary albedo by reflecting shortwave (SW) solar radiative flux back to space to cool the Earth.

At 5 microns it's 0.1 + 0.45 = 0.55: pollution reduces albedo by > = 8 %.

Svensmark demonstrated the amplification possible from cosmic rays and cloud formation changing the Albedo by more than enough to account for any observed temperature change over the past 150 years and other cycles come into play for the longer period global temperature variations.

Their belief came about because the optical physics of aerosols, originating from Sagan and introduced to climate modelling by his ex-students, Lacis and Hansen in 1974 at GISS / NAS, predicts the cloud part of «global dimming», the increase of albedo by aerosols supposed to hide present CO2 - AGW.

For example, I show in «The Tropical Thunderstorm Hypothesis» that the change from clear to cumulus conditions increases the albedo by about 60 w / m2, a large effect.

The researchers believe this will increase a city's overall albedo by about 0.10.

The initial warming also reduces the surface albedo by melting snow and sea - ice, which likewise constitutes a positive feedback because snow and ice are effective reflectors of sunlight.

Scientists say increasing the planet's albedo by 1 percent — by painting roads and roof tops white — might be enough to halt global warming.

Not exact matches

That «backsplash» of protons, which was discovered by CRaTER and is known as the moon's radiation «albedo,» is caused by the partial reflection of galactic cosmic rays off the moon's surface.

Image portrays the Earth, the Moon and Comet 67P / Churyumov - Gerasimenko showing how they would appear in the same light conditions, taking in account their relative albedos, the percentage of light reflected by the body.

Over the current century, the model projects that the average albedo for the entire ice sheet will fall by as much as 8 percent, and by as much 10 percent on the western edge, where the ice is darkest today.

The new study by Stefanie Lutz, postdoc at the German Research Centre for Geosciences GFZ and at the University of Leeds, shows a 13 per cent reduction of the albedo over the course of one melting season caused by red - pigmented snow algal blooms.

«There is a potential risk that if you cool the planet by albedo modification, it could provide less incentive to reduce reliance on fossil fuels,» says Marcia McNutt, a geophysicist, current editor - in - chief of Science and chair of a committee that evaluated climate intervention techniques for the U.S. National Academy of Sciences.

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.

We have shown that albedo is strongly affected by and dependent upon the development and dominance of microbial communities.

And by knocking down trees, which absorb sunlight, a mammoth could cause more sun to be reflected, increasing the cooling albedo effect on the permafrost.

All the previous albedo data had been collected by manned monitoring stations, which as a rule are only active for short periods.

Albedo is a ratio of how much sunlight (and its thermal radiation) is reflected back into space by a given surface.

The boundaries of ancient valley walls are defined by textural and albedo changes and are also associated with lateral river migration.

In contrast, the Scripps team opted to directly correlate albedo measurements made by NASA's CERES instrument data with observations of sea ice extent made by the Special Sensor Microwave Imager (SSM / I) radiometers aboard Defense Meteorological Satellite Program satellites.

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.

When the analysis was confined to the area covered by ice, an equivalent decline in albedo was found during June - August.

The trends revealed by the data were clear: The average albedo in the northern area of the Arctic Ocean, including open water and sea ice, is declining in all summer months (May - August).

Critics argue that albedo modification and other «geoengineering» schemes are risky and would discourage nations from trying to reduce their emissions of carbon dioxide, the heat - trapping gas that comes from the burning of fossil fuels and that is causing global warming by absorbing increasing amounts of energy from sunlight.

Albedo modification would work by lacing the atmosphere with tiny particles or aerosols that would reflect sunlight and mimic natural processes.

Fires in the planet's northern regions, he said, speed permafrost melt and contribute to the albedo effect by creating dark, exposed stretches of land.

Albedo modification might also work by using aerosols to seed cloud formation in a lower atmospheric layer called the troposphere.

So the real choice is between exploring albedo modification openly or in relative secrecy, he says: «I believe in sunshine and democracy, and I really think this should be done by the U.S. government and in a transparent way.»

The surface's reflectivity, which scientists call albedo, could decrease by as much as 10 percent by the end of the century, the study finds.

«If you can time your emissions so they have the least impact then you will not trigger these very sensitive regions to start warming by this ice albedo feedback process.»

Pavement albedo affects buildings both directly, by reflecting more or less sunlight to nearby buildings, and indirectly, by changing the outside air temperature.

By far the most common urban pavement material is asphalt concrete, which is dark, and has a low solar reflectance, or «albedo.»

Pluto and Charon have surfaces dominated by volatile ices, with large variations in color and albedo.

As more vegetation was removed by the introduction of livestock, it increased the albedo (the amount of sunlight that reflects off the earth's surface) of the land, which in turn influenced atmospheric conditions sufficiently to reduce monsoon rainfall.

Virtually ice - free summers in the arctic sea could well arrive by 2030, with troubling implications for accelerated albedo feedback and possibly disruptive changes in the jet stream.

However, there is an additional shortcoming due to the fact that the equilibrium temperature is also affected by the ratio of the Earth's geometrical cross-section to its surface area as well as how much is reflected, the planetary albedo (A).

Some of the strategies proposed by authors, such as improving the «urban albedo» — or a city's reflectivity — could have unintended consequences such as glare, he noted.

Due to the positive feedback caused by the high albedo of snow and ice, susceptibility to falling into snowball states might be a generic feature of water - rich planets with the capacity to host life.

The phase variation can be modeled either by a planet with a geometric albedo of $ 0.30 \ pm 0.06 $ in the Kepler bandpass, or by thermal emission from the surface of the planet at $ \ sim $ 3000K.

Unless low - level cloud albedo substantially decreased during this time period, the reduced solar absorption caused by the reported enhancement of cloud cover would have resulted in cooling of the climate system that is inconsistent with the observed temperature record.»

The solar radiative forcing is TSI in Watts per square meter (W - m - 2) divided by 4 to account for spherical geometry, and multiplied by 0.7 to account for planetary albedo (Meehl 2002).

Also, the reduction in forests caused by the ice's expansion increases albedo.

Overall, this study demonstrates that the climate simulated by a numerical climate model can be sensitive to how the snow albedo is treated.

Courtillot et al. commit the «flat Earth» error from which our article draws its name: they give a misleading impression of the comparison of forcing by solar variability relative to greenhouse gas forcing by failing to take into account the Earth's spherical geometry and albedo.

With higher precipitation, portions of this snow may not melt during the summer and so glacial ice can form at lower altitudes and more southerly latitudes, reducing the temperatures over land by increased albedo as noted above.