Sentences with phrase «which changes the albedo»

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 is a small forcing, but it caused ice to retreat in the north, which changed the albedo.

Not exact matches

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).

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.

Perhaps you might want to read that paper as well as «Climate Change and Trace Gases», available in many places, which argues for an albedo flip mechanism and (relatively) short timescales for icesheet response to forcing, based on paleo data.

In our own modelling, we have improved the calculations to reduce the amount of numerical diffusion (which helped a lot), and increased resolution (which also helped), but changes to the ocean model also have a big impact, as do Arctic cloud processes and surface albedo parameterisations, so it gets complicated fast.

The resulting increased / decreased ice is amplified by «various feedbacks, including ice - albedo, dust, vegetation and, of course, the carbon cycle which amplify the direct effects of the orbital changes.»

As an analogy, if I told you that I was going to paint my white car black and that I expected it would get hotter on sunny days as a result, you would probably start asking questions about what the temperature of the paint was when I applied it and how those molecules heated up or cooled down, ignoring the relevant factor which is this: By painting the car black, I am changing the car's albedo and thus changing the radiative balance between the car and the sun on sunny days.

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.

The cooling (that results from the change in albedo) necessarily reduces the amount of H2O in the atmosphere, which is a positive feedback that further cools the planet.

It doesn't have to be CO2 — in this case it's seasonal insolation changes which cause an expansion of ice cover which cause a change in the planet's overall albedo.

During that process, upward LW radiation reaching the upper atmosphere will increase (depending on albedo / solar heating feedbacks), which will change the equilibrium temperature of the upper atmopshere again.

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).

So albedo change (owing to changes in orbital forcing, which is what melts the ice sheets) was comparable to, and probably larger than, the CO2 change.

What I was trying to raise was the general issue of changes in albedo, which would seem far more effective ways of altering the radiation balance of the planet than the IEEE device, no matter how ingenious.

(while maintaining solar heating, which is actually a hypothetical excercise in part because removing clouds would change the albedo, though albedo could be artificially maintained by other means for the sake of this thought experiment)

I continued to question 4, changed insolation and suface albedo as indicated (just like in question 2, which was marked right), and set TOA radiative inbalance back to 0.

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...»

Increasing CO2 does increase the greenhouse effect, but there are other factors which determine climate, including solar irradiance, volcanism, albedo, orbital variations, continental drift, mountain building, variations in sea currents, changes in greenhouse gases, even cometary impacts.

«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...»

Only a change in the surface area of lakes frozen or a change in timing (which would both affect earth albedo) would have any climate significance.

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.

However, even a smaller figure (I had calculated about 0.17 W / m ^ 2 based on your inflated figure for total planetary albedo, but you can check it out) is still significant when compared with the total flux imbalance, which I think is a more informative comparison than an arbitrarily selected change in cloud cover, because it compares the sea ice reduction with the effects of all climate variations that have been operating in recent years..

Your albedo change represents a value of about 0.17 W / m ^ 2, which if correct, would make Arctic sea ice reduction in recent years potentially a major contributor to ongoing imbalances.

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.

Its warming effect, however, is simultaneously amplified and dampened by positive and negative feedbacks such as increased water vapor (the most powerful greenhouse gas), reduced albedo, which is a measure of Earth's reflectivity, changes in cloud characteristics, and CO2 exchanges with the ocean and terrestrial ecosystems.

Most of it temperature related which was driven by change in albedo due to Earth dynamics — some 25W / m2 less reflected shortwave.

By so doing, we are ignoring other low frequency forcings (such as long wavelength changes in TSI and albedo) which would have to be included to make any sense of the data.

Appreciable changes in climate are the result of changes in the energy balance of the Earth, which requires «external» forcings, such as changes in solar output, albedo, and atmospheric greenhouse gases.

Dr. Roy Spencer has proposed a hypothesis whereby some unknown internal mechanism causes cloud cover to change, which in turn changes the reflectivity (albedo) of the planet, thus causing warming or cooling.

The albedo value changes with the size of the daytime global cloud cover, which is the umbrella of the globe.

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..

Leaf area and biomass respond to climate which can lead to changes in albedo and transpiration.

Team Purple could check for UHI, albedo change, pollution etc theories to see if those, combined with the greenhouse effect, can produce predictions which actually match reality, something Red's efforts conspicuously fail to do.

Among other things, it ignores: heating due to changes in albedo; «waste» heat (which may be several times greater than power consumption); convection and advection; etc., etc..

In order to determine the solar contribution, we have to start with the solar radiative forcing, which is the change in total solar irradiance (TSI) in Watts per square meter (W / m2) divided by 4 to account for spherical geometry, and multiplied by 0.7 to account for planetary albedo (Meehl 2002).

The main albedo change in the last 60 years is probably ice / snow loss, which is another positive feedback to the change and not independent.

There are other factors such as albedo change, buildings that diminish surface winds, and anthropogenic heat sources from anthing that consumes fuel or electricity to produce work and waste heat which buildings then help to trap.

This is the limit imposed by albedo which can only change so much with the current arrangement of the continents.

Land albedo will have changed several times and of course aerosols which they mention in passing.

Pielke seniors thing is that land use changes leadto albedo changes which lead to more heat absorbed, so actually the warming isn't much to do with CO2 and so there isn't much of a problem.

In the case of the 100 kyr ice age cycles, that forcing is high northern latitude summer insolation driven by predictable changes in Earth's orbital and rotational parameters — aka, Milankovitch theory — which has the intial effect of melting glaciers, thereby reducing albedo at those latitudes.

Now, that statement I have just made applies to the insolation itself, but a far greater non-linearity to be anticipated, and which I discussed in my essay, is the effect of the changing insolation in terms of altering the albedo values and distribution, and therefore the overall consequences of that changing insolation.

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.

To me, the prime suspect behind any real warming is changes in cloud cover which may have reduced albedo and may have allowed the oceans to absorb more solar energy.

When you compare this with the actual surface temperature of ~ 288 K and the temperature in absence of the greenhouse effect but no change in albedo of ~ 255 K, what we can say is the follows: The greenhouse effect due to all the greenhouse gases (water vapor, clouds, and the long - lived GHGs like CO2 and CH4) raises the temperature of the Earth by an amount of ~ 33 K (which is 288K — 255K); the albedo due to cloud reduces the temperature by ~ 17 K (which is 272 K — 255 K); the net effect of both the GHGs and the cloud albedo is ~ 16 K (which is 288K — 272K).

Just changing the Albedo percentage to a number I believe it was (0.333) and then changing the orange cell to 89 % simulates the surface temperature properly but the troposphere temperature drops to -11.9 C, which is not the way I understand the climate models would simulate it.

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)

The only thing that I would contend could be added would be long slow cumulative changes in solar output other than raw TSI namely changes in the mix of particles and wavelengths over longer periods of time such as MWP to LIA to date and which seem to have some effect on surface pressure distribution and global albedo so as to alter solar shortwave into the oceans and thus affecting the energy available to the ENSO process.