You know not how much you ask. The physics of clouds is very complex. Starting with the basics, clouds contain liquid water. Water molecules are close enough to interact and that changes the spectral profile. Whereas the spectrum of water vapor is a forest of rotational bands centered at about 1650 cm-1 and 3600 cm-1 (bending and stretching, respectively), the spectrum of liquid water has strong and broad absorptions in these regions. Water forms short lived crystals: dimers, trimers, tetramers, etc. As the reduced mass goes up, the frequency goes down. This is particularly noticeable in the OH stretch where the broad absorption is a superposition of many small cluster bands. At the low end, librational bands appear from about 1280 cm-1 down. Water is essentially opaque at wavelengths in the mid IR above 8 microns and will behave like a black body in the earth's thermal radiation region. (Water becomes transparent again at very low frequencies) There are several confounding factors that have not been addressed above. First, water droplets are best described by the Mei Theory of scattering. Briefly, the scattering and absorption are functions of the droplet size and complex refractive index. Secondly, many droplets contain a dust nucleation core. The electrical properties of the dust affect the optical properties of the droplet. This is a very involved calculation based on Maxwell's equations. Finally, there are effects from the droplet size distribution and interactions between droplets (rainbow, for example). I noticed that Dr. James Hansen included these factors in his radiative transfer code. I was impressed. Not many scientists willingly dive into that kind of mathematical rigor.

I'll answer with one part I know and one part I have a pretty good idea of:

For the visible spectrum of incoming solar radiation, clouds generally reflect about 20% back to space, absorb about 3% (water droplets) and allow the rest to pass through to the ground.

Clouds do have a significant affect on AGW. I.e., since clouds have both the property of general cooling AND warming we need to determine their net effect. And perhaps more importantly, clouds are central to the estimation of climate sensitivity and whether there is weak or strong positive feedback due to increasing water vapor.

Hi Darwinist These couple of links may help you work it out

http://en.wikipedia.org/wiki/Oxide

http://en.wikipedia.org/wiki/Ion

http://en.wikipedia.org/wiki/Corona_disc...

http://en.wikipedia.org/wiki/Ionic_condu...

All the above links are the reasons this works http://www.australianrain.com.au/trials/...

The structure of a cloud would determine it's interactions and emissions.http://en.wikipedia.org/wiki/Atomic_orbi...

Edit for those that don't get it , This link describes what heat is http://www.chelationtherapyonline.com/te... from here you might if smart enough see why adding electrical energy to a reagen of air already ionized will increase its magnetic potential

http://en.wikipedia.org/wiki/Electric_fo... The problem with science at the moment IS not what's being communicated to the public BUT what's left out. WHY ?

I cannot "view" Kano's question "at this time" so it is difficult to guess what this question is really driving at. Although the additional detail, "how significant to the question of AGW is any of the above?," is at least indicative. I got a minimal response when I recently asked more directly what role clouds play in climate change. The suggestion then, however, was that clouds on balance enhance rather than retard anthropogenic increases in average long term global temperature. http://answers.yahoo.com/question/index;...

how can i know. imean how can anyone know.what happens is what happens.why should we know

Just following on from Kano's question.

Are they as black body radiators, or do they radiate at specific wavelengths in a similar way to greenhouse gasses?

And what about absorption; clearly clouds are highly reflective at visible wavelengths, but is the reflection 100%? If not, then what happens to the rest? (Also, as an aside, is reflection the best word to use?)

What about non visible wavelengths; the same for visible? ... and are there any wavelengths to which clouds are transparent?

Finally, how significant to the question of AGW is any of the above?