Sentences with phrase «with average albedo»

Wouldn't it be a pretty good first approximation to model a one square meter of earth and the atmosphere above it with average albedo, average solar input, average cloud cover, etc?

Not exact matches

[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?)

(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).

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.)

So we are left with little sense of how much some «average» macrovariables like albedo, vary day to day and hour by hour as clouds come and go and land use and natural cover vary

That is an average available with an assumed fixed albedo.

Taking the pessimistic assumption that there would eventually be an «ice free summer» in the Arctic, I come up with a future reduction of the average albedo of the Earth of:

When the planet's sun is 4 billion years younger it's output is 33 % less than it is today, so under clear skies with an albedo for water of 0.1, the average incident solar energy would be ~ 274 watts / m2.

It is arguably one of the most advanced of the seven in its impacts, with a 2011 GRL report putting its warming effect as equivalent to around 30 % of atmospheric anthro - CO2, and the recent report putting albedo loss from arctic sea - ice decline since»79 as providing a forcing equivalent on average to that from 25 % of the anthro - CO2 levels during the period.

Given a planet with a certain albedo, a certain distance from a star of a given luminosity, one can determine what the average temperature of the planet would be in the absence of a greenhouse effect.

The solar flux is 1366 watts per sq m so with the hemisphere having twice the cross sectional area this averages to 688 watts / sq m The albedo reduces this by 30 % to 478 watts / sq m About half of this energy is incorporated into the Earth systems growing plants creating weather etc leaving 239 watts / sq m which must be returned to space.

The 21st century can be expected to be with lower solar activity, less deflection of cloud - seeding galactic cosmic rays, higher average cloud cover, a more reflective planetary albedo, and a cooler planet..

Given the earth with an albedo similar to the moon (i.e. all rocks) it would have an average surface temperature well below freezing.

In the absence of absorption of terrestrial radiation by the atmosphere (and with the other caveats about still having the same albedo and such), that average temperature would have to be 255 K at the surface because of radiative balance and then the temperature would decrease with height at the lapse rate from there.

For example, the global average effect of any change in albedo from using solar power would be rather small in comparison to mitigation of climate change if that solar power is used (to displace fossil fuels) for a sufficient time period (example: if a 10 % efficient PV panel with zero albedo (reflectivity for solar (SW) radiation) covered ground with an albedo of 25 — 30 %, the ratio of total increased heating to electricity generation would be similar to that of many fuel - combusting or fission - powered power plants (setting aside inverter and grid efficiency, etc., but still it would be similar).

The problem doesn't go away however because the earth has a non-zero albedo too and it isn't known nearly as well as the moon's with, depending on who you ask, an average albedo in the range of 32 % which is primarily the result of some 70 % being shrouded by clouds of some sort at any given instant.

Obviously, we are currently in transition and our global atmospheric cell structures are going to shift rapidly with broadly expanding Hadley cell and collapsing Arctic cell leading to meridional migration of average cloud cover and reduced albedo.

Hence this wild notion on the problem of albedo, how do we define the average colour of your classic redhead in prime condition but with lots of freckles?

In the almost sure knowledge that the earth never experienced a runaway greenhouse even with ancient CO2 levels 10 to 20 times greater than today, these anti-science scoundrels insist with a «high level of confidence» that this amplification is real and it's based on nothing more than faster than expected surface temperature rise in the past few decades which can be TOTALLY explained by multi-decadal cyclic behavior in ocean currents, trade winds, and / or solar magnetic activity causing small global average albedo changes.