Sentences with phrase «vapor feedback values»

When you consider that the «Greenhouse» effect is logarithmic, wouldn't that affect subsequent water vapor feedback values?

Not exact matches

(PS regarding Venus — as I have understood it, a runaway water vapor feedback would have occured when solar heating increasing to become greater than a limiting OLR value (Simpson - Kombayashi - Ingersoll limit — see http://chriscolose.wordpress.com/2010/08/23/climate-feedbacks-part-1/ — although I should add that at more «moderate» temperatures (warmer than today), stratospheric H2O increases to a point where H escape to space becomes a significant H2O sink — if that stage worked fast enough relative to solar brightening, a runaway H2O case could be prevented, and it would be a dry (er) heat.

Since many of these processes result in non-symmetric time, location and temperature dependant feedbacks (eg water vapor, clouds, CO2 washout, condensation, ice formation, radiative and convective heat transfer etc) then how can a model that uses yearly average values for the forcings accurately reflect the results?

(Within the range where water vapor feedback is runaway, zero change in external forcing»cause s» a large change in climate; the equilibrium surface temperature, graphed over some measure of external forcing, takes a step at some particular value.)

If a doubling of CO2 resulted in a temperature increase of approximately 1 K before any non-Planck feedbacks (before water vapor, etc.), then assuming the same climate sensitivity to the total GHE, removing the whole GHE would result in about a (setting the TOA / tropopause distinction aside, as it is relatively small relative to the 155 W / m2 value) 155/3.7 * 1 K ~ = 42 K. Which is a bit more than 32 or 33 K, though I'm not surprised by the difference.

Willis Eschenbach says: August 14, 2011 at 9:58 am «My point is that the main issue is not the exact value of the feedback from clouds and from water vapor, because those values are not what affect the operating point temperature of the tropics.

There is much discussion as to the value of the climate sensitivity, which swirls around whether there is net positive or negative feedback from things like clouds and water vapor.

My point is that the main issue is not the exact value of the feedback from clouds and from water vapor, because those values are not what affect the operating point temperature of the tropics.

They most certainly don't cancel one another as the water vapor feedback is much larger and the cloud feedback either adds or is small to allow for measured values of 2 C per doubling.

But I am not about to buy in on the AGW premise of IPCC, which is based on a mean ECS value of 3.2 C (with a «fat tail»), which is in turn based on net positive feedback from clouds and a water vapor feedback based on essentially maintaining constant relative humidity with warming, all of which is solely based on model predictions and not on empirical evidence.

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.

In his 1906 publication, Arrhenius adjusted the value downwards to 1.6 °C (including water vapor feedback: 2.1 °C).

«Interestingly, the true feedback is consistently weaker than the constant relative humidity value, implying a small but robust reduction in relative humidity in all models on average, as weighted by the water vapor kernel.»

I thought that the rough numbers were that the water vapor feedback about doubles the climate sensitivity from the no - feedback value and then the lapse rate feedback takes about half of that back, leaving about a 1.5X - or - so increase in the climate sensitivity.