progressiveslol wrote on Aug 19
th, 2012 at 4:55pm:
muso wrote on Aug 19
th, 2012 at 4:39pm:
You'll have to explain what you mean. Maybe you could give us an example of what you mean by like for like. What about tropical convective clouds then? Some pretty major feedbacks there.
What factors determine "like for like" as you put it?
I am talking like for like in every way. It would have to be height, density, convection, even chemical make up should be similar ect ect.
... then you might as well throw in geographical location and season if you want like for like. You do realise that cloud altitudes are much higher in tropical latitudes for one thing? For example, high clouds range from about 6000 metres to about 18,000 metres in the tropics, whereas similar clouds are found between about 5000 metres and 13,000 metres at mid latitudes.
Cloud altitude has a considerable effect on radiative feedback for several reasons. For a start, feedback can have negative and positive components. Usually positive feedbacks result from reflection/emission of IR radiation back to ground level from the cloud base, whereas negative feedbacks result from radiation from the cloud ceiling to outer space. The altitude of the clouds also has impacts on increasing the moisture content of the upper atmosphere, which increases radiative feedback etc.
So in practice it's extremely difficult to account for variations in planetary boundary layer (among other factors) when calculating cloud feedbacks. Studies like Miller, M., Ghate, V., Zahn, R., (2012) are intended to improve our understanding of regional cloud feedback processes and hence improve the resolution of regional climate prediction.
Of course, every single denialist site on the blogosphere will misinterpret, clutch at straws,seize the wrong end of the stick and just about everything else they can do.
The sad thing is that the likes of Anthony Watts is about as ignorant on the subject as you are, based on your responses.