Sentences with phrase «in global albedo»

Secondly, the actual mean albedo is still not that well known — true, recent estimates are lower than the earlier numbers which most GCMs were tuned against, but I would be hesitiant in assuming that a 1 % change in global albedo will suddenly make a big difference in response.

In my articles to date I have been unwilling to claim anything as grand as the creation of a new model of climate because until now I was unable to propose any solar mechanism that could result directly in global albedo changes without some other forcing agent or that could account for a direct solar cause of discontinuities in the temperature profile along the horizontal line of the oceanic thermohaline circulation.

Major changes in global albedo move at a glacial pace.

I was surprised there was no mention of changes in global albedo or cloud cover in the paper, but I assume that AR5 includes them under «natural variability» rather than forcings.

If we allow that all those clouds are cumulus with an albedo of 0.8 and that they block water with an albedo of 0.1, that translates to a change in global albedo of 0.014.

If this change in global albedo is what is causing global warming, how did the process get started?

Not exact matches

Albedo modification «is not a solution to global warming, it is only a way to avoid, perhaps, a tipping point in the climate.»

In her global maps of Europa, Callisto and Ganymede, the color gradient represents the surface temperature — blue means colder and therefore, presumably a more reflectively surface (higher albedo).

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).

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 impossiblIn 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 impossiblin 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.

I was interested not so much in the forcing effect of clouds themselves so much as the change in albedo which might result from a change in the overall extent of global cloud cover.

[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?)

While the local, seasonal climate forcing by the Milankovitch cycles is large (of the order 30 W / m2), the net forcing provided by Milankovitch is close to zero in the global mean, requiring other radiative terms (like albedo or greenhouse gas anomalies) to force global - mean temperature change.

On the possibility of a changing cloud cover «forcing» global warming in recent times (assuming we can just ignore the CO2 physics and current literature on feedbacks, since I don't see a contradiction between an internal radiative forcing and positive feedbacks), one would have to explain a few things, like why the diurnal temperature gradient would decrease with a planet being warmed by decreased albedo... why the stratosphere should cool... why winters should warm faster than summers... essentially the same questions that come with the cosmic ray hypothesis.

I think that only illustrates the bizarre use of the global average and models that in effect suggest cutting down trees would increase albedo and cool the planet.

Increasing the negative feedback, as might happen in the atmosphere if global warming creates increased cloud cover (hence albedo), can increase the amplitude of the oscillations.

In Hansen Nazarenko 2004, Hansen wrote that «Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic... is about one quarter of observed global warming.&raquIn Hansen Nazarenko 2004, Hansen wrote that «Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic... is about one quarter of observed global warming.&raquin the Arctic... is about one quarter of observed global warming.»

(Orbital forcing doesn't have much of a global annual average forcing, and it's even concievable that the sensitivity to orbital forcing as measured in terms of global averages and the long - term response (temporal scale of ice sheet response) might be approaching infinity or even be negative (if more sunlight is directed onto an ice sheet, the global average albedo might increase, but the ice sheet would be more likely to decay, with a global average albedo feedback that causes warming).

Is there a point in global warming where albedo would suddenly increase instead of decreasing?

I have a question for the ice scientists: If an ice free Arctic summer becomes routine, say in 2013, how much will the absorption feedback vs. normal albedo raise global temperature?

http://www.springerlink.com/content/lm0024kv72t3841w/ «The simulated magnitude of hydrological changes over land are much larger when compared to changes over oceans in the recent marine cloud albedo enhancement study since the radiative forcing over land needed (− 8.2 W m − 2) to counter global mean radiative forcing from a doubling of CO2 (3.3 W m − 2) is approximately twice the forcing needed over the oceans (− 4.2 W m − 2).

I've sometimes thought that global cataclysms like the largest volcanic eruptions would disrupt the glacial records by many years, like Oruanui eruption c. 26500bp, as these would induce unrecorded behavior in weather and other things, f.e. the huge ash deposits might decrease the albedo so much a local melting event happens.

Global climate models have successfully predicted the rise in temperature as greenhouse gases increased, the cooling of the stratosphere as the troposphere warmed, polar amplification due the ice - albedo effect and other effects, greater increase in nighttime than in daytime temperatures, and the magnitude and duration of the cooling from the eruption of Mount Pinatubo.

Nighttime increases in cloud cover will contribute to global warming — only daytime changes and the concurrent increase in albedo would give negative forcing.

«Our results suggest that, in contrast to other proposals to increase planetary albedo, offsetting mean global warming by reducing marine cloud droplet size does not necessarily lead to a drying, on average, of the continents.

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).

If CO2 in the Anthropocene atmosphere contributes to re-vegetating currently arid areas as it did post-LGM, we should expect an even greater warming feedback from CO2 than is assumed from water vapor and albedo feedbacks, due to decreased global dust - induced albedo and increased water vapor from transpiration over increased vegetated area.

Furthermore since modelers tweak cloud parameters to match global albedo and achieve energy balance, and because the AR4 models achieve a good match to global average surface temperatures, there are at least partially compensating errors elsewhere in the models for both albedo and temperature.

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).

The water vapor, lapse - rate and ice - albedo feedbacks in isolation enhance the global warming that would result from increasing CO2 concentrations alone to around +2.2 °C.

bozzza - The differences in the Arctic are perhaps 1/4 the ocean thermal mass as global ocean averages, small overall size (the smallest ocean), being almost surrounded by land (which warms faster), more limited liquid interchanges due to bottlenecking than the Antarctic, and very importantly considerable susceptibility to positive albedo feedbacks; as less summer ice is present given current trends, solar energy absorbed by the Arctic ocean goes up very rapidly.

In the real world the most obvious and most common reason for an increase in the speed of energy flow through the system occurs naturally when the oceans are in warm surface mode and solar input to the oceans due to reduced global albedo is high as apparently occurred during the period 1975 to 199In the real world the most obvious and most common reason for an increase in the speed of energy flow through the system occurs naturally when the oceans are in warm surface mode and solar input to the oceans due to reduced global albedo is high as apparently occurred during the period 1975 to 199in the speed of energy flow through the system occurs naturally when the oceans are in warm surface mode and solar input to the oceans due to reduced global albedo is high as apparently occurred during the period 1975 to 199in warm surface mode and solar input to the oceans due to reduced global albedo is high as apparently occurred during the period 1975 to 1998.

In this new study, the researchers showed that increasing the albedo of a 1m2 surface by 0.01 would have the same effect on global temperature, over the next 80 years, as decreasing emissions by around 7 kg of CO2.

ii) The oceans appear to vary in the rate at which they release solar energy back to the air which affects atmospheric composition via humidity, clouds and global albedo.

In my last comment, «global albedo feedbacks» was meant to refer specifically to global snow / ice albdeo feedbacks.

E.g., human - caused albedo variations from desertification, and to some extent tropical deforestation, were connected with past global climate changes by Sagan et al. (1979); a pioneering model confirming «the long - held idea that the surface vegetation... is an important factor in the Earth's climate» was Shukla and Mintz (1982); Amazon Basin: Salati and Vose (1984); more recently, see Kutzbach et al. (1996).

That allows latitudinal sliding of the jets and climate zones below the tropopause leading to changes in global cloudiness and albedo with alters the amount of energy getting into the oceans.»

The sun is clearly driving changes in global air circulation and thus global albedo as per my model:

6) The main cloud bands move more poleward to regions where solar insolation is less intense and total global albedo declines via a reduction in global cloud cover due to shorter lines of air mass mixing.

Human - caused global warming contributes to the summer Greenland warming (Figure 3), which causes snow to melt earlier, which causes decreased local albedo, which contributes to record Greeland ice sheet decline, which further decreases local albedo, which in turn contributes to the Arctic sea ice decline.

In terms of mitigation strategy, this appears to indicate that even an overnight termination of global anthro - CO2 outputs would already be offset by Albedo loss by around 30 %.

Conserving the viability of forestry seems to me a third reason to view a program of Albedo Restoration as the necessary and sufficient complement in a Troika mitigation strategy, alongside the objectives of halting the ongoing disruption of global agriculture and decelerating the main interactive feedbacks.

A simple method for estimating the global radiative forcing caused by the sea - ice - albedo feedback in the Arctic is presented.

«Kopacz et al. used a global chemical transport model to identify the location from which the BC arriving at a variety of locations in the Himalayas and the Tibetan Plateau originates, after which they calculated its direct and snow - albedo radiative forcings... they say that observations of black carbon (BC) content in snow «show a rapidly increasing trend,»... «emissions from northern India and central China contribute the majority of BC to the Himalayas,» and that «the Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries.»»

But assuming there is an unknown oscillating oceanic mechanism, for example, which varies, in important parts of the globe, the low clouds, there can be variation in the albedo, regardless of global temperature.

To date, while various effects and feedbacks constrain the certainty placed on recent and projected climate change (EG, albedo change, the response of water vapour, various future emissions scenarios etc), it is virtually certain that CO2 increases from human industry have reversed and will continue to reverse the downward trend in global temperatures that should be expected in the current phase of the Milankovitch cycle.

So the Earthshine project first reveals the global high albedo of the more equatorward jets from the 1960s when the sun was less active during cycle 20 (although cycle 20 was still high in historical terms) and there was some tropospheric cooling.

BUT, other important / related parameters — BRDF (bidirectional reflectance distribution function)-- albedo i. /: 00 solar local time Neural network based on CYCLOPES and MODIS / wrong ALSO Need to make assumptions about carbon lost via respiration to go from GPP to / Cox et al. (2000) Acceleration of global warming due to carbon - cycle feedbacks in a coupled / / JRC / FastOpt: http://www.fastopt.com/topics/publications.htmlhttp://www.fastopt.com/topics/publications.html 50 0 = water; 1 /

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.

However what I do say is that if other factors alter albedo (or any other component of the global energy budget) then the jets will move in response to that other forcing in order to try to move back towards equilibrium between the temperature of the ocean surface and the temperature at the tropopause.