Sentences with phrase «of ice sheet albedo»

Not exact matches

Albedo is a measure of the reflectance of the ice sheet.

What G&T are missing is the linear effect of water vapour accelerating the ice albedo effect of change in size of the sea ice sheets.

This mitigates the albedo feedback, as does the lowering in sea level that accompanies the formation of ice sheets.

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.

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.

Ice sheet albedo forcing is estimated to have caused a global mean forcing of about — 3.2 W m — 2 (based on a range of several LGM simulations) and radiative forcing from increased atmospheric aerosols (primarily dust and vegetation) is estimated to have been about — 1 W m — 2 each.

How the albedo of the Greenland ice sheet in July 2017 compared to the average for July from 2000 - 2009.

Other factors would include: — albedo shifts (both from ice > water, and from increased biological activity, and from edge melt revealing more land, and from more old dust coming to the surface...); — direct effect of CO2 on ice (the former weakens the latter); — increasing, and increasingly warm, rain fall on ice; — «stuck» weather systems bringing more and more warm tropical air ever further toward the poles; — melting of sea ice shelf increasing mobility of glaciers; — sea water getting under parts of the ice sheets where the base is below sea level; — melt water lubricating the ice sheet base; — changes in ocean currents -LRB-?)

Note also that going back to the ice ages, the glacial - interglacial temperature swing can not be explained without full water vapour feedback on top of both the ice sheet albedo and CO2 effects.

What G&T are missing is the linear effect of water vapour accelerating the ice albedo effect of change in size of the sea ice sheets.

For example, the ice age — interglacial cycles that we have been locked in for the past few million years seem to be triggered by subtle changes in the earth's orbit around the sun and in its axis of rotation (the Milankovitch cycles) that then cause ice sheets to slowly build up (or melt away)... which changes the albedo (reflectance) of the earth amplifying this effect.

This implies a forcing of 3 W / m2 for albedo changes presumably due to additional ice / snow sheets.

This was a relatively stable climate (for several thousand years, 20,000 years ago), and a period where we have reasonable estimates of the radiative forcing (albedo changes from ice sheets and vegetation changes, greenhouse gas concentrations (derived from ice cores) and an increase in the atmospheric dust load) and temperature changes.

I agree that most people will not fully understand the implications of this, because most don't know diddly about Hadley cells, Ferrel cells, the Polar cell, albedo, latent or sensible heat, and mechanisms by which solar energy can be transported from the Arctic to melt more of the Greenland ice sheet.

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.

(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).

Based on evidence from Earth's history, we suggest here that the relevant form of climate sensitivity in the Anthropocene (e.g. from which to base future greenhouse gas (GHG) stabilization targets) is the Earth system sensitivity including fast feedbacks from changes in water vapour, natural aerosols, clouds and sea ice, slower surface albedo feedbacks from changes in continental ice sheets and vegetation, and climate — GHG feedbacks from changes in natural (land and ocean) carbon sinks.

«Summer melting on lower reaches of the ice sheets and on ice shelves introduces the «albedo flip» mechanism.

Simulating the variation of the ice sheet's albedo using a regional climate model — Modèle Atmosphérique Régionale (MAR), which some members of the team helped develop — indicated that increasing temperatures and melting accompanied by snow grain growth and greater bare ice exposure account for about half the decline, the scientists report.

So how much of the temperature swings are orbitally forced and how much GHG forced and how much ice sheet albedo forced?

«The positive ice - albedo feedback acts to amplify the climate change as a consequence of the melting of sea ice and ice sheets in the Northern Hemisphere.

The new study quantitatively assessed how surface ice algae contribute to darkening of the ice sheet, and found the algae reduce the ice sheet's albedo significantly more than non-algal materials, like mineral particles and black carbon.

A CO2 pulse in the atmosphere will take centuries to finally return to original levels, and that is completely ignoring any potential feedbacks from other parts of the system (ie temperatures raised for centuries could result in massve methane releases and loss of signficant low albedo ice sheets etc.) The experiments I am aware of that show improved plant growth in elevated CO2 levels require that all additional biological needs are amply provided for.

With the albedo - flip kicking in, the energy poured into killing off millennia - old MY ice will then go into the warming of the Arctic Ocean itself, with the result of longer and longer melt seasons each year & a corresponding ramp - up of ice loss from both the Greenland Ice Sheet and the West Antarctic Ice Sheice will then go into the warming of the Arctic Ocean itself, with the result of longer and longer melt seasons each year & a corresponding ramp - up of ice loss from both the Greenland Ice Sheet and the West Antarctic Ice Sheice loss from both the Greenland Ice Sheet and the West Antarctic Ice SheIce Sheet and the West Antarctic Ice SheIce Sheet.

(Other things, like ice sheets, albedo, etc, while super important, are also over time reflection of that.)

http://earthobservatory.nasa.gov/IOTD/view.php?id=83672 http://www.nytimes.com/2014/05/13/science/earth/collapse-of-parts-of-west-antarctica-ice-sheet-has-begun-scientists-say.html It will add about 10 feet according to an interview with one of the scientists involved; but over a long time and fairly vague time frame, unless reinforcing processes (carbon release from melting permafrost, shallow ocean bottom warmingn in the form of methane from clathrates), a major reduction in earth's albedo from permafrost, net ice sheet, and total sea ice, continue to increasingly accelerate the process.

The melting of the ice sheets and the change in albedo and the change in the sea levels were all feedbacks as a result of the insolation change.

If these plumes of warm air operated in the same way during the last glaciation as they do know then they would make short work of ice sheets that were hanging around because of the albedo effect, this is possible because not all the northern hemisphere mid latitude land surface was covered with ice throughout the period of glaciation and might explain why glaciations terminate quickly

Comparisons of the impacts of shortwave and longwave radiative forcing appropriate over the ice sheets are not straightforward, but taking summer half - year insolation variations in shortwave (Figure 3), and assuming an albedo of 0.5 for melting ice, variations in summertime shortwave forcing exceed the direct CO2 radiative forcing by about a factor of five.

The remaining slow drift to lower GMT and pCO2 over glacial time, punctuated by higher - frequency variability and the dust − climate feedbacks, may reflect the consequences of the growth of continental ice sheets via albedo increases (also from vegetation changes) and increased CO2 dissolution in the ocean from cooling.

Albedo change due to LGM — Holocene vegetation change, much of which is inherent with ice sheet area change, and albedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foAlbedo change due to LGM — Holocene vegetation change, much of which is inherent with ice sheet area change, and albedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foalbedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foalbedo climate forcing.

To avoid long response times in extreme climates, today's ice sheets are assigned surface properties of the tundra, thus allowing them to have a high albedo snow cover in cold climates but darker vegetation in warm climates.

Glacial — interglacial oscillations of the CO2 amount and ice sheet size are both slow climate feedbacks, because glacial — interglacial climate oscillations largely are instigated by insolation changes as the Earth's orbit and tilt of its spin axis change, with the climate change then amplified by a nearly coincident change of the CO2 amount and the surface albedo.

Greenland and West Antarctic Ice Sheets — Like sea - ice, ice sheets have a high albedo, locally reflecting much of the Sun's enerIce Sheets — Like sea - ice, ice sheets have a high albedo, locally reflecting much of the Sun's eSheets — Like sea - ice, ice sheets have a high albedo, locally reflecting much of the Sun's enerice, ice sheets have a high albedo, locally reflecting much of the Sun's enerice sheets have a high albedo, locally reflecting much of the Sun's esheets have a high albedo, locally reflecting much of the Sun's energy.

An ice sheet teetering on the edge of melting away is going to have a huge response because just a little extra energy changes the albedo.

The glaciers and ice caps / sheets ECV is of importance to climate models and albedo, water balance, sea level, and radiation budget climate studies.

The land ECV breakout group was asked to consider 10 ECVs related to surface observations: glaciers and ice caps / sheets, snow cover, soil moisture, fire disturbance, lakes, biomass, land cover, surface albedo, fraction of absorbed photosynthetically active radiation (FPAR), and leaf area index (LAI).

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.

These include intrinsic limitations in current observational capabilities (e.g., spatial and radiometric resolution of currently available spaceborne sensors) and limitations on how accurately surface energy balance models handle ice sheet albedo.

A fall of just a couple of degrees and you have increasing Ice sheets, Increasing Albedo, growing Glaciers, in short..

Another way of saying this is to estimate ECS from the last glacial - interglacial transition, the albedo change due to ice sheet melting is taken as a forcing rather than as a feedback.