Comments on: Visualizing Atmospheric Radiation – Part Eleven – Stratospheric Cooling

By: The Climate Change Debate Thread - Page 2355

The Climate Change Debate Thread - Page 2355 — Wed, 03 Apr 2013 20:02:25 +0000

[...] in this article) will also affect the change in stratospheric temperature from increasing CO2 Visualizing Atmospheric Radiation – Cooling Sign in or Register Now to [...]

By: Wonderland and Radiative Forcing – Part Two | The Science of Doom

Wonderland and Radiative Forcing – Part Two | The Science of Doom — Sun, 03 Mar 2013 08:35:53 +0000

[...] The second left is effectively the “radiative forcing”, and we can see that the above the tropopause (at about 200 mbar) the net flux change with height is constant. This is because the stratosphere has come into radiative balance. Refer to the last article for more explanation. On the right hand side, with all feedbacks from this one change in Wonderland, we can see the famous predicted “tropospheric hot spot” and the cooling of the stratosphere. [...]

By: Wonderland, Radiative Forcing and the Rate of Inflation « The Science of Doom

Thu, 21 Feb 2013 11:45:02 +0000

[...] If we plotted separately the up and down flux we would find that they have a slope, but the slope of the up and down would be the same. Net absorption of radiation going up balances net emission of radiation going down – more on this in Visualizing Atmospheric Radiation – Part Eleven – Stratospheric Cooling. [...]

By: Mitzi Lancaster

Mitzi Lancaster — Thu, 07 Feb 2013 16:31:26 +0000

We could improve on this simple greenhouse model by viewing the atmosphere as a vertically continuous absorbing medium, rather than a single discrete layer, applying the energy balance equation to elemental slabs of atmosphere with absorption efficiency df(z) proportional to air density, and integrating over the depth of the atmosphere. This is the classical ” gray atmosphere” model described in atmospheric physics texts. It yields an exponential decrease of temperature with altitude because of the exponential decrease in air density, and a temperature at the top of atmosphere of about 210 K which is consistent with typical tropopause observations (in the stratosphere, heating due to absorption of solar radiation by ozone complicates the picture). See See Planetary skin for a simple derivation of the temperature at the top of the atmosphere. Radiative models used in research go beyond the gray atmosphere model by resolving the wavelength distribution of radiation, and radiative-convective models go further by accounting for buoyant transport of heat as a term in the energy balance equations. Going still further are the general circulation models (GCMs) which resolve the horizontal heterogeneity of the surface and its atmosphere by solving globally the 3-dimensional equations for conservation of energy, mass, and momentum. The GCMs provide a full simulation of the Earth’s climate and are the major research tools used for assessing climate response to increases in greenhouse gases.

By: Kristian

Kristian — Sat, 02 Feb 2013 14:44:41 +0000

DeWitt Payne,

Thanks.

By: DeWitt Payne

DeWitt Payne — Sat, 02 Feb 2013 14:08:47 +0000

Tropical upwelling is also what drives Brewer-Dobson circulation.

By: DeWitt Payne

DeWitt Payne — Sat, 02 Feb 2013 14:04:22 +0000

Kristian,

Could you point to any consistent real-world measurements of the evolution of stratospheric CO2-content that could back up your implication that increased CO2 in the stratosphere itself, not in the troposphere below, has significantly helped cooling the stratosphere?

Sure.

http://www.nature.com/nature/journal/v316/n6030/abs/316708a0.html

The growth rate of the atmospheric CO2 abundance caused by anthropogenic emission, which varies between 1.0 and 1.5 p.p.m.v. yr–1 at ground level1, is also observed at all stratospheric heights up to 35 km. The shape of the profiles suggests that excess CO2 above 20 km enters the stratosphere through tropical upwelling rather than mid-latitude diffusion. The time lag of this height region with respect to the tropospheric CO2 level is ~5 yr.

By: Kristian

Kristian — Sat, 02 Feb 2013 13:58:23 +0000

DeWitt Payne,

Could you point to any consistent real-world measurements of the evolution of stratospheric CO2-content that could back up your implication that increased CO2 in the stratosphere itself, not in the troposphere below, has significantly helped cooling the stratosphere?

Because, like I said in my first comment to this thread, there is no steady decrease in terrestrial radiation coming UP through the tropopause (from tropo- to stratosphere) during the last decades of global warming and tropospheric CO2 increase. And according to theory (i.e. the real-world application of it), we wouldn’t expect there to be.

What I object to is the whole conflating of tropospheric warming with stratospheric cooling that seems so deep-rooted in the public mind.

Those two processes don’t necessarily have anything to do with one another.

If the stratosphere is (partly) cooled by increasing stratospheric CO2 content, then fine. That’s because in the stratosphere, radiation runs the show. In the troposphere, convection runs the show.

By: Kristian

Kristian — Sat, 02 Feb 2013 13:00:55 +0000

DeWitt Payne,

Of course I didn’t miss that point. I’ve read the article, after all. But stating (more as a routine genuflection to dogma) that the residual cooling is ‘broadly consistent with the predicted impact of increasing greenhouse gases’ while in the actual paper pointing to an increased Brewer-Dobson circulation as the most likely cause of the residual, isn’t in my mind strengthening the CO2 side of this argument.

By: Visualizing Atmospheric Radiation – Part Eight – CO2 Under Pressure « The Science of Doom

Sat, 02 Feb 2013 07:53:26 +0000

[...] Part Eleven – Stratospheric Cooling - why the stratosphere is expected to cool as CO2 increases [...]