Sentences with phrase «surface albedo feedbacks»

Using feedback parameters from Fig. 8.14, it can be estimated that in the presence of water vapor, lapse rate and surface albedo feedbacks, but in the absence of cloud feedbacks, current GCMs would predict a climate sensitivity (± 1 standard deviation) of roughly 1.9 °C ± 0.15 °C (ignoring spread from radiative forcing differences).

The failures to reproduce the increase in precipitation (Wentz) and the surface albedo feedbacks (Roesch) were quite enough.

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.

However, the contributions of water vapour / lapse rate and surface albedo feedbacks to sensitivity spread are non-negligible, particularly since their impact is reinforced by the mean model cloud feedback being positive and quite strong.

Then, one can presumably decompose this «total forcing» into its components which might include WV feedbacks, cloud feedbacks, surface albedo feedbacks etc..

Equilibrium sensitivity, including slower surface albedo feedbacks, is 6 °C for doubled CO2 for the range of climate states between glacial conditions and ice - free Antarctica.»

New techniques that evaluate surface albedo feedbacks have recently been developed.

Plotting GHG forcing (7) from ice core data (27) against temperature shows that global climate sensitivity including the slow surface albedo feedback is 1.5 °C per W / m2 or 6 °C for doubled CO2 (Fig. 2), twice as large as the Charney fast - feedback sensitivity.»

(57j) For surface + tropospheric warming in general, there is (given a cold enough start) positive surface albedo feedback, that is concentrated at higher latitudes and in some seasons (though the temperature response to reduced summer sea ice cover tends to be realized more in winter when there is more heat that must be released before ice forms).

Thus, the positive λSW of the CMIP5 ensemble average and the resulting energy accumulation by enhanced ASR under GHG forcing can be expected based only on the robust physics of the water vapor feedback and the surface albedo feedback in the absence of any changes in clouds... ``

The SW surface albedo feedback has a value of +0.3 ± 0.1 W m − 2 K − 1 (43, 45).

A number of processes, other than surface albedo feedback, have been shown to also contribute to the polar amplification of warming in models (Alexeev, 2003, 2005; Holland and Bitz, 2003; Vavrus, 2004; Cai, 2005; Winton, 2006b).

The surface albedo feedback is assessed here to be likely positive.

Including water vapor feedback, lapse rate feedback and surface albedo feedback, but excluding cloud feedback, the IPCC models predict a value of 1.9 °C ± 0.15 °C.

Seasonal changes in SWR from clear skies have little to do with the surface albedo feedback that will follow global warming (aka ice - albedo feedback).

Arctic climate change is strongly influenced by the surface albedo feedback, which acts to

Since the TAR, some progress has been made in quantifying the surface albedo feedback associated with the cryosphere.

In AOGCMs, the water vapour feedback constitutes by far the strongest feedback, with a multi-model mean and standard deviation for the MMD at PCMDI of 1.80 ± 0.18 W m — 2 °C — 1, followed by the (negative) lapse rate feedback -LRB--- 0.84 ± 0.26 W m — 2 °C — 1) and the surface albedo feedback (0.26 ± 0.08 W m — 2 °C — 1).

The three studies, using different methodologies to estimate the global surface albedo feedback associated with snow and sea ice changes, all suggest that this feedback is positive in all the models, and that its range is much smaller than that of cloud feedbacks.

These runs are examined for evidence of accelerated climate change associated with the removal of sea ice, particularly due to increasing surface albedo feedback.

Not exact matches

Let's just mention the ice - albedo feedback, which is very different at (hypothetically) e.g. 100K surface temperature with probably «snowball earth» and at 300K with no ice at all.

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).

This chemical weathering process is too slow to damp out shorter - term fluctuations, and there are some complexities — glaciation can enhance the mechanical erosion that provides surface area for chemical weathering (some of which may be realized after a time delay — ie when the subsequent warming occurs — dramatically snow in a Snowball Earth scenario, where the frigid conditions essentially shut down all chemical weathering, allowing CO2 to build up to the point where it thaws the equatorial region, at which point runaway albedo feedback drives the Earth into a carbonic acid sauna, which ends via rapid carbonate rock formation), while lower sea level may increase the oxidation of organic C in sediments but also provide more land surface for erosion... etc..

These models all suggest potentially serious limitations for this kind of study: UVic does not simulate the atmospheric feedbacks that determine climate sensitivity in more realistic models, but rather fixes the atmospheric part of the climate sensitivity as a prescribed model parameter (surface albedo, however, is internally computed).

Slow insolation changes initiated the climate oscillations, but the mechanisms that caused the climate changes to be so large were two powerful amplifying feedbacks: the planet's surface albedo (its reflectivity, literally its whiteness) and atmospheric CO2 amount.

The model considers all relevant feedback processes caused by changes of water vapour, lapse - rate, surface albedo or convection and evaporation.

A conceptual model is presented where, through a number of synergistic processes and positive feedbacks, changes in the ultraviolet / blue flux alter the dimethyl sulphide flux to the atmosphere, and in turn the number of cloud condensation nuclei, cloud albedo, and thus sea surface temperature.

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.

re 454 wili — of course, introducing additional feedbacks like vegetation albedo (boreal forests replacing tundra) and methane hydrate / clathrate, etc, could concievably make it runaway — again, limited by C reservoir and land area / latitude ranges (and some places would probably see a surface albedo increase).

, (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-?)

But both CO2 and solar - caused surface + tropospheric warming will cause at least some similar latitudinal and seasonal patterns of change within the troposphere + surface via the patterns of albedo feedback and lapse rate feedback.

I have a question about the potential albedo feedback effect on a ablating ice sheet surface.

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).

Is it the long - awaited, predicted and scientifically reasonable CO2 fertilization feedback effect on the oceans» vast biomass of CO2 - consuming cyanobacteria, albeit also driven by the (literally) «shit - loads» of nitrogen compounds the human race is also pumping into the oceans — thereby shifting sea surface albedos, reducing evaporation rates and troposphere relative humidities (ringing any bells here, bros)?

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.

Arctic sea ice extent reconstruction - Kinnard et al. 2011 Sea ice albedo feedback - NASA Polar jet stream - NC State University Greenland ice sheet surface melt - NASA Permafrost distribution in the Arctic - GRID - Arendal Atmospheric methane concentration - NOAA ESRL Russia plants flag at North Pole - Reuters

A substantial reduction in water vapor (shown below, from Lacis et al (2010) as well as increase in the surface albedo are important feedbacks here, showing that removing the non-condensing greenhouse gases (mostly CO2) in the atmosphere can collapse nearly the entire terrestrial greenhouse effect.

It is notable that this feedback is arguably the most difficult to control due to the period of several decades that would be required to restore the upper oceans» natural temperature by an Albedo Restoration program lowering the surface air temperature.

AGW climate scientists seem to ignore that while the earth's surface may be warming, our atmosphere above 10,000 ft. above MSL is a refrigerator that can take water vapor scavenged from the vast oceans on earth (which are also a formidable heat sink), lift it to cold zones in the atmosphere by convective physical processes, chill it (removing vast amounts of heat from the atmosphere) or freeze it, (removing even more vast amounts of heat from the atmosphere) drop it on land and oceans as rain, sleet or snow, moisturizing and cooling the soil, cooling the oceans and building polar ice caps and even more importantly, increasing the albedo of the earth, with a critical negative feedback determining how much of the sun's energy is reflected back into space, changing the moment of inertia of the earth by removing water mass from equatorial latitudes and transporting this water vapor mass to the poles, reducing the earth's spin axis moment of inertia and speeding up its spin rate, etc..

They have to interpret innumerable feedback loops, all the convective forces, the evaporation, the winds, the ocean currents, the changing albedo (reflectivity) of Earth's surface, on and on and on.

In the Arctic, one familiar feedback effect is sea ice albedo, which measures how well the Earth's surface reflects sunlight.

They also warn that feedback patterns are starting to emerge in the shape of the ice albedo effect: ice reflects heat away from the surface, so as it decreases in extent so warming quickens.

The net effect is a greater (reflecting) albedo, less sunlight reaching the surface, and therefore a negative feedback that reduces the original warming from increasing CO2.

Slow insolation changes initiated the climate oscillations, but the mechanisms that caused the climate changes to be so large were two powerful amplifying feedbacks: the planet's surface albedo (its reflectivity, literally its whiteness) and atmospheric CO2 amount.

There are, however, also slow feedbacks like the change in surface albedo from the reduction of snow cover that contribute to TCS / ECS.

This radiative response by the system is due predominantly to increased thermal radiation, but it is modified by climate feedbacks such as changes in water vapour, clouds and surface albedo, which affect both outgoing longwave and reflected shortwave radiation.

Finds that the feedback for which the evidence of ongoing changes is most compelling is the surface albedo - temperature feedback, which is amplifying temperature changes over land (primarily in spring) and ocean (primarily in autumn — winter)

Figure 1: Schematic diagram of the equilibrium fast - feedback climate sensitivity and Earth system sensitivity that includes surface albedo slow feedbacks.

Vegetation cover changes caused by land use can alter regional and global climate through both biogeochemical (emissions of greenhouse gases and aerosols) and biogeophysical (albedo, evapotranspiration, and surface roughness) feedbacks with the atmosphere, with reverse effects following land abandonment, reforestation, and other vegetation recoveries (107).

Using measured amounts of GHGs during the past 800000 years of glacial — interglacial climate oscillations and surface albedo inferred from sea - level data, we show that a single empirical «fast - feedback» climate sensitivity can account well for the global temperature change over that range of climate states.