Sentences with phrase «snow and ice albedo»

(In the full 4 - dimensional climate, responses can also tend spread horizontally by convection (advection) and temporally by heat capacity, though «fingerprints» of horizontal and temporal variations in RF (externally imposed and feedback — snow and ice albedo, for example) can remain — this spreading is somewhat different as it relies in part on the circulation already present as well as circulation changes)

The bottom line is that uncertainties in the physics of aerosol effects (warming from black carbon, cooling from sulphates and nitrates, indirect effects on clouds, indirect effects on snow and ice albedo) and in the historical distributions, are really large (as acknowledged above).

You are welcome to try something similar with global radiative forcing fluctuation, but if you do it will be rather tricky to isolate the cloud effect, since you have the snow and ice albedo effect to deal with then, which are largely temperature - related feedbacks.

Not exact matches

White areas covered with snow and ice reflect sunlight; the effect is called albedo.

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.

With the albedo of older snow and ice at about 0.6, the open ocean will absorb more heat than the ice capped ocean.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

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.

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.

He then uses what information is available to quantify (in Watts per square meter) what radiative terms drive that temperature change (for the LGM this is primarily increased surface albedo from more ice / snow cover, and also changes in greenhouse gases... the former is treated as a forcing, not a feedback; also, the orbital variations which technically drive the process are rather small in the global mean).

The importance of orbital variations, of the greenhouse gases CO2, CH4 and N2O, of the albedo of land ice sheets, annual mean snow cover, sea ice area and vegetation, and of the radiative perturbation of mineral dust in the atmosphere are investigated.

Specifically, increasing the snow albedo delayed the melting of snow and sea ice in spring, which increased the albedo difference to the experiment in which snow grains were assumed spherical.

On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

26 Paul W asked, «On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

In addition, since the global surface temperature records are a measure that responds to albedo changes (volcanic aerosols, cloud cover, land use, snow and ice cover) solar output, and differences in partition of various forcings into the oceans / atmosphere / land / cryosphere, teasing out just the effect of CO2 + water vapor over the short term is difficult to impossible.

[1] CO2 absorbs IR, is the main GHG, human emissions are increasing its concentration in the atmosphere, raising temperatures globally; the second GHG, water vapor, exists in equilibrium with water / ice, would precipitate out if not for the CO2, so acts as a feedback; since the oceans cover so much of the planet, water is a large positive feedback; melting snow and ice as the atmosphere warms decreases albedo, another positive feedback, biased toward the poles, which gives larger polar warming than the global average; decreasing the temperature gradient from the equator to the poles is reducing the driving forces for the jetstream; the jetstream's meanders are increasing in amplitude and slowing, just like the lower Missippi River where its driving gradient decreases; the larger slower meanders increase the amplitude and duration of blocking highs, increasing drought and extreme temperatures — and 30,000 + Europeans and 5,000 plus Russians die, and the US corn crop, Russian wheat crop, and Aussie wildland fire protection fails — or extreme rainfall floods the US, France, Pakistan, Thailand (driving up prices for disk drives — hows that for unexpected adverse impacts from AGW?)

Increased CO2 does not warm the atmosphere, it melts the snow and ice reducing global albedo, and that causes AGW.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

Our analysis of observations from four years of field experiments indicates that seasonal ice undergoes an albedo evolution with seven phases; cold snow, melting snow, pond formation, pond drainage, pond evolution, open water, and freezeup.

The modeling in Moelg and Hardy is done using an albedo model for clean snow and ice, which yields similar values to those measured in the Antarctic.

28, Alastair McDonald: Increased CO2 does not warm the atmosphere, it melts the snow and ice reducing global albedo, and that causes AGW.

This positive climate feedback is greater than expected from the additional forcing alone, due to amplification by reduced surface albedo through melting of continental snow and decreased sea - ice coverage, especially in the wintertime.

black soot has also been found by a recent university of california study to be the direct cause of the albedo warming effect on the otherwise highly reflective and pristine white arctic ice & snow.

, (3) changes in surface albedo of snow & ice due to changes in temperature and deposition of mineral and black carbon particulates, and last, but arguably most significantly (4) the intensity of the positive feedback that comes from the inevitable -LRB-?)

Ecological succession and biological evolution would also provide hysteresis (for example, I read of an idea that under some conditions, bogs will tend to take over forests; these bogs will have a higher albedo than forest when snow falls, thus potentially bringing an ice age...).

On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

For instance, the effect of soot making snow and sea ice darker has a higher efficacy than an equivalent change in CO2 with the same forcing, mainly because there is a more important ice - albedo feedback in the soot case.

Analysis of observed declines in sea ice and snow coverage from 1979 to 2008 suggests that the NH albedo feedback is between 0.3 and 1.1 W m — 2 °C — 1 (Flanner et al., 2011).

Furthermore, decline in snow cover and sea ice will tend to amplify regional warming through snow and ice - albedo feedback effects (see Glossary and Chapter 9).

Since it reflects the capacity of the climate system to absorb heat, it may be influenced by the planetary albedo (sea - ice and snow) and ice - caps, which respond to temperature changes.

Snow and ice has a high albedo and when it is replaced by sea water or soil and tundra the albedo drops and there is warming, this is simple optics.

Both are related to feedback mechanisms which can amplify or dampen initial changes, such as the connection between temperature and the albedo associated with sea - ice and snow.

Re 9 wili — I know of a paper suggesting, as I recall, that enhanced «backradiation» (downward radiation reaching the surface emitted by the air / clouds) contributed more to Arctic amplification specifically in the cold part of the year (just to be clear, backradiation should generally increase with any warming (aside from greenhouse feedbacks) and more so with a warming due to an increase in the greenhouse effect (including feedbacks like water vapor and, if positive, clouds, though regional changes in water vapor and clouds can go against the global trend); otherwise it was always my understanding that the albedo feedback was key (while sea ice decreases so far have been more a summer phenomenon (when it would be warmer to begin with), the heat capacity of the sea prevents much temperature response, but there is a greater build up of heat from the albedo feedback, and this is released in the cold part of the year when ice forms later or would have formed or would have been thicker; the seasonal effect of reduced winter snow cover decreasing at those latitudes which still recieve sunlight in the winter would not be so delayed).

... A new sea - ice albedo parameterization scheme has been developed and implemented in ECHAM5 general circulation model, and includes important components like albedo decay due to snow aging, ice thickness dependency and an explicit treatment of melt pond albedo.

Global average temperature is lower during glacial periods for two primary reasons: 1) there was only about 190 ppm CO2 in the atmosphere, and other major greenhouse gases (CH4 and N2O) were also lower 2) the earth surface was more reflective, due to the presence of lots of ice and snow on land, and lots more sea ice than today (that is, the albedo was higher).

It is not that the polar regions are amplifying the warming «going on» at lower latitudes, it is that any warming going on AT THE POLES is amplified through inherent positive feedback processes AT THE POLES, and specifically this is primarily the ice - albedo positive feedback process whereby more open water leads to more warming leads to more open water, etc. *** «Climate model simulations have shown that ice albedo feedbacks associated with variations in snow and sea - ice coverage are a key factor in positive feedback mechanisms which amplify climate change at high northern latitudes...»

«Climate model simulations have shown that ice albedo feedbacks associated with variations in snow and sea - ice coverage are a key factor in positive feedback mechanisms which amplify climate change at high northern latitudes...»

I attribute this to rapidly retreating snow cover and sea ice replacing high albedo surfaces with low albedo.

Add a dramatic increase of CO2 and methane emissions to the albedo declines of sped up Arctic ice and snow cover losses and you may still witness a runaway situation.

When the oceans are warm and the Arctic is open, it does snow like crazy and that does increase ice albedo and earth does stop warming and does start cooling.

When the oceans are cold and the Arctic is frozen, it does not snow much and that does allow a decrease in ice albedo and earth does stop cooling and does start warming.

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.

Does anyone track global snow / ice extent and relate it to albedo?

Estimating the cloudy sky albedo of sea ice and snow from space.

Ice ages come on slowly as the albedo from greater and greated snow coverage increases causing greater and greater cooling, but end rapidly as the melt back rapidly decreases the albedo.

When the flux is increased, the planet undergoes a decrease in surface albedo which is due to the melting of the permanent polar ice caps and the reduced seasonal snow cover.

This estimate was refined by Hansen and Nazarenko (2004), who used measured BC concentrations within snow and ice at a wide range of geographic locations to deduce the perturbation to the surface and planetary albedo, deriving an RF of +0.15 W mâ $ «2.

This estimate does not include the semi-direct effect or the BC impact on snow and ice surface albedo (see Sections 2.5.4 and 2.8.5.6)

In the case of albedo this is a positive feedback because the warmer a hemisphere gets the lower its albedo as its ice and snow disappear.

The principal feedbacks are water vapor, snow - ice albedo, clouds, and lapse rate.