Sentences with phrase «albedo over»

For example, the initial development of a continental ice sheet increases albedo over a portion of Earth, reducing surface absorption of sunlight and leading to further cooling.

Does anyone know of a good graph which shows the change in albedo over the last... well, as far back as possible?

Yet measured variations in earth's albedo over just several years has it changing by more watts / m2 than the highest estimate of alleged anthropogenic warming.

Greenhouse warming that is stronger over land and in the Northern Hemisphere tends to strengthen the monsoon, but increases in planetary albedo over the continent due to aerosol forcing and / or land - use change tend to weaken it.

In this article I present prima facie evidence that the ongoing natural increase in spring insolation occurring at high northern latitudes, coupled with the positive feedback effect of the resultant snow and ice loss reducing the region's mean albedo over summer, comprises just such a causative agency.

Longer duration = higher average albedo over a day.

Intercomparison Between in situ and AVHRR Polar Pathfinder - derived Surface Albedo over Greenland Remote Sensing of the Environment 75 (3): 360 - 374.

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.

Not exact matches

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 unmanned SRB buoy we built made it possible for the first time to generate continuous data on albedo and other properties of sea ice over a long period,» says Dr Gerland.

Because of concerns over embargoes, the team has only reluctantly disclosed the dimensions and volume of the comet, for instance, and it has yet to publicly describe the comet's albedo, or reflectivity.

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.

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.

Over a five - year period, scientists found that albedo did increase slightly.

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.

But they do at least have certain basic physical principles in their cloud representations — clouds over ice have less albedo effect than clouds over water, you don't get high clouds in regions of subsidence, stable boundary layers lead to marine stratus, etc..

There was more ice around in the LGM and that changes the weighting of ice - albedo feedback, but also the operation of the cloud feedback since clouds over ice have different effects than clouds over water.

The albedo and CO2 feedbacks amplified weak orbital forcings, the feedbacks necessarily changing slowly over millennia, at the pace of orbital changes.

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.

I would expect the albedo effect presented by clouds to be weak over the mostly snow / ice covered Antarctica, but Svensmark argues that the clouds here warm rather than cool the temperature.

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.

I should have been more accurate — the presentation says «reversibility suggests natural variations» and I presume this is because over the period 1984 - 2003 the albedo is seen to both decrease and increase and there is an assumption that an anthropogenic variation would be one - way.

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...).

So for example deglaciation warmed global mean temps by about 5 C over 10k years with a radiative forcing of about 6.5 W / m2 (total of both GHG increases and albedo decreases).

For example, the optical thickness of the CO2 in the atmosphere (if you see an error in this list of things independent of climate, see below), the incident solar radiation and it's distribution over time and space (latitude), variations in surface albedo between ocean, rock, vegetation, etc.).

Orbital forcing causes ice ages or ends them by redistributing incoming solar radiation over seasons and latitudes so that ice sheet growth or decay is more or less favorable on a regional basis, with a resulting global average albedo feedback.)

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).

The ambiguity over the definition of ice - free is not really important as far as the strong albedo feedbacks magnifying the warming of the region, so is kind of a red herring in the discussion.

This implies that the CRF levels must have systematically decreased over time, causing a long - term decrease in the low cloud fraction and hence a long - term reduction in the planetary albedo, that again would be responsible for the warming.

Is there a discernible point, maybe in a model, that includes reduced albedo in the summer, that might show an acceleration of melting above the average temperature increase curve for the region so that ocean warmth has an increasing role over atmospheric??

The exposed open water caused by the wind divergence may absorb some additional sunlight and melt more ice than usual over the next few weeks (temperature - albedo feedback)[related NASA animation], but given that the sun is well on its way to setting for the winter, I think this effect will be fairly minimal.

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.

The rise of CO2 from 270ppm to now over 400ppm, the extent of equatorial and sub tropical deforestation, the soot deposits on the polar ice caps, the increase in atmospheric water vapour due to a corresponding increase in ocean temps and changes in ocean currents, the extreme ice albedo currently happening in the arctic etc, etc are all conspiring in tandem to alter the climate as we know it.

And all those scientists roaming all over the place up there... wonder what's the albedo differential of yellow snow.

Would the much lower albedo result in higher temperatures over a broad enough region to accelerate the crossing of other «tipping points» elsewhere, such as the release of large quantities of methane / CO2 from Siberian peat?

The idea was that the arctic did not freeze over, leading to more water uptake, and massive snows that decreased albedo.

All of this is reason for everyone and his brother, aunt and sister to greatly reduce their own GHG emissions, and to scream bloody murder till every corporation, institution and governmental body they have any influence over to immediately institute policies to rapidly bring down GHG emissions and look at reliable ways of drawing down atmospheric CO2 levels directly (especially replanting grasslands in the north, tree planting toward the equator where albedo change is not an issue).

Albedo from medium / low level clouds warms or cools the ocean surface by increasing or decreasing over time across the global surface.

This albedo has been changing over recent decades and is responsible for most ocean warming with the increased maintained higher solar levels.

But the climate is changing so rapidly that we already face volatile scenarios like the possibility of escalating international conflicts over potentially dangerous albedo hacking experiments.

Have you ever heard of aerosols, volcanoes, albedo, and the largest control knob of Earth's climate over its 4.5 billion year existence, CO2?

For instance, Han et al. (1998) showed that cloud albedo decreases with decreasing droplet size for the optically thinner clouds over the oceans.

The mechanism by which the effect of oceanic variability over time is transferred to the atmosphere involves evaporation, conduction, convection, clouds and rainfall the significance of which has to date been almost entirely ignored due to the absence of the necessary data especially as regards the effect of cloudiness changes on global albedo and thus the amount of solar energy able to enter the oceans.

The albedo enhancement over the cloud - rain areas tends to increase the net (IR + albedo) radiation energy to space more than the weak suppression of (IR + albedo) in the clear areas.

Logical simple statistics (and one can actually calculate the Albedo - climate - impact of Antarctica icing over — surprise, it is exactly -2.0 C) versus fantasy made - up statistics.

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.

The author claims the climate models are building up the affects of the processes like ice albedo from its pieces, ie rather than abstracting in to the gain formula, the models are adding up all the individual pieces, on a grid, over time.

If you look at visible satellite pictures you see the reflection of the sun over a small area, and the brightness could be from albedos in this range.

The albedo change resulting from the snowline retreat on land is similarly large as the retreat of sea ice, so the combined impact could be well over 2 W / sq m. To put this in context, albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, estimated by the IPCC to be 1.6 W / sq m in 2007 and 2.29 W / sq m in 2013.»

Keep in mind there's a dearth of insolation at high latitudes so albedo becomes increasingly less important so snow cover over land doesn't mean as much.