Monday, February 03, 2020

Again in the Margins

While pursuing a chimera through his sea of bullshit, Eli came upon a second paper from Syukuro Manabe and Richard Wetherald, not the 1967 one in the Journal of Atmospheric Sciences, Thermal equilibrium of the atmosphere with a given distribution of relative humidity which pretty much nailed the 2x CO2 climate sensitivity, but a later one, The Effects of Doubling the CO2 Concentration on the climate of a General Circulation Model which appeared in the same journal, but eight years later (1975).

Before passing on to the material at hand Eli would like to point out that even the title of the first paper puts the wood to the plaint that climate science has always neglected the role of water vapor, but let us move on to the subject at hand. Before getting to business, it is worth quoting some of the conclusions from the second 1975 paper

1) In general, the temperature of the model troposphere increases resulting from the doubling of the concentration of carbon dioxide. This warming in the higher latitudes is magnified two to three times the overall amount due to the effects of snow cover feedback and the suppression of the vertical mixing by a stable stratification.
2) the temperature of the model stratosphere decrease because of the larger emission from the stratosphere into space caused by the greater concentration of CO2.
There is more (including more precipitation and evaporation), but what caught Eli's eye was a series of comments on Rasool and Schneider. Eli has always pointed out that R&S (and S agreed at about the time of the second paper) was that they over estimated the increased aerosol loading of the atmosphere and underestimated greenhouse gas forcing, but Manabe and Wetherald point to other problems
1) Rasool and Schneider did not take into consideration the fact that the temperature change in the stratosphere has an opposite sign to that in the troposphere
Since R&S were using Hansen's Venus model, not much of a surprise but something the Bunny had not seen before
2) The absorption of solar radiation is altered if the atmospheric temperature and accordingly also the water vapor content changes.  This factor was not considered by Rasool and Schneider
Which is all about the Foote Effect (TM Eli Rabett)

1 comment:

Chase S said...

Walter Hannah had a nice writeup about this paper (it's also included in The Warming Papers). The ocean is essentially an infinitely evaporating swamp.