For example. If I meet someone for the first time and they are really sick. My only knowledge of that person is that they are sick. I didnt know them prior. Same as earth and its climate changes.

In case you check in while you’re still in Florence, you might want to have a look at my page on David: A New Perspective.

Ciao!

Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations, De-Zheng Sun, Yongqiang Yu, Tao Zhang

Radiative and Dynamical Feedbacks Over the Equatorial Cold-Tongue: Results from Nine Atmospheric GCMs D.-Z. Sun and T. Zhang, C. Covey and S.A. Klein, W.D. Collins, J. J. Hack, J.T. Kiehl, and G.A. Meehl, I. M. Held, M. Suarez

Radiative and Dynamical Feedbacks Over the Equatorial Cold-Tongue: Results from Seven Atmospheric GCMs, D.-Z. Sun and T. Zhang, C. Covey and S. Klein, W.Collins, J. Kiehl, and J. Meehl, I. Held, M. Suarez

By comparing the response of clouds and water vapor to ENSO forcing in nature with that in AMIP simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate of the strength of the negative cloud albedo feedback and (2) an overestimate of the positive feedback from the greenhouse effect of water vapor. … These biases, however, highlight the continuing difficulty that models have to simulate accurately the feedbacks of water vapor and clouds on a time-scale we have observations.

It may be that there is a big difference between the tropics and elsewhere, but according to Sun all the models are hypersensitive to water vapor in the tropics and get clouds and lateral feedback wrong.

My comment on Dessler, a few paragraphs long, has been in review at GRL for 5 months. Have a comment back from Dessler. Still waiting.

http://landshape.org/enm/propagation-of-uncertainty-through-dessler/

Regarding Lindzen’s paper, his results are actually fairly similar to Spencer’s-in fact the feedback from LW (OLR) is actually near zero and the feedback from shortwave is strongly negative:

http://www.leif.org/EOS/2009GL039628-pip.pdf

Which he reckons is the result of either no water vapor feedback or the cancellation of the WV feedback by the Iris Effect. Considering the similarity of their overall results, one is left to wonder, what of Spencer’s positive LW feedback and much stronger SW feedback? The answer could be that Spencer is examining the whole Earth, while Lindzen’s ERBE results are for just the tropics. If so, the probable situation would be:

Tropics:

Iris and WV feedback operating
fairly strong SW negative feedback operating

Extratropics:

strong WV feedback operating
ice albedo feedback
very strong SW negative feedback

I’ll have to ask Spencer about the possibility of a regional analysis to see if in fact his and Lindzen’s results are compatible. But the above describes the situation that would need to be the case for that to be so, and may serve as a sort of hypothesis to be tested.

As for how good their methods are, let’s see what happens in the next few months. If they are seriously flawed, someone is bound to notice and wave the result like a bloody shirt.

Nicely posed, but I think the water, in all its phases, feedback is variable, dependent upon need. There are so many components of the feedbacks that chaos, or a random walk between the two lines marking the ice ages and the in between times, reigns. I don’t know how the system is self-centering back and forth between those two boundaries, but it does.
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1) The Dessler and Zhang (2009) paper apparently shows from the 6 years of validated AIRS temperature and humidity data (2003 to 2008) a confirmation of a strong positive water vapour feed back. This conclusion, however, is partly founded on the use of the radiative kernels developed by Sodon et al which themselves are derived from models. The Lindzen (2009) paper infers a negative feedback by comparing total OLR from ERBE non-scanner data against temperature. Roy Spencer (March 2009 blog) confirms the magnitude of the IR response inferred by Dessler and Zhang, but argues that the key is probably in the SW response, which renders the total feedback negative. What are the arguments for and against these positions?
Have a great holiday!

If a doubling of CO2 is pretty well established that a non corresponding rise in temperature would occur without a positive feedback why do we attack CO2 and not the feedback that causes the AGW?

Don’t give them any ideas!