What percentage of income solar radiation does Earth's atmosphere absorb?

Answer 1

19% of incoming solar radiation is absorbed by the atmosphere (and clouds).

Answer 2

The correct answer, from an authoritative source, is about 20%.

(About 22% is reflected by the atmosphere.) The following

answer was written before mine :

"Scattered" is a better word to use than "absorbed" because as soon as a molecule absorbs a photon, it re-emits it in a random direction. It doesn't stay in the molecule forever. That being said, our atmosphere treats different electromagnetic wavelengths differently, because of the different gasses in our atmosphere. Depending on the shape of a gas molecule, it might scatter one type of radiation, but let another type pass straight through. It's hard to say exactly what percent of radiation gets blocked, because, not only does our atmosphere absorb different types, but the sun emits different types. In order to answer this question, I'll break it down type-by-type:

• Gamma rays- The sun doesn't emit many, and our atmosphere scatters all of them.
• X Rays- The sun emits a little more x-rays than gamma rays, but still not very much, and, again, our atmosphere scatters all of them.
• UV Rays- The sun emits a decent amount of UV rays, and the ozone layer scatters most of them.
• Visible light- The sun emits more visible light than any other wavelength, and our atmosphere hardly scatters any of it.
• Infrared light- The sun also emits a large amount of IR waves. Greenhouse gasses, like CO2 and water vapor, manage to scatter about 50% of it.
• Microwaves- The sun emits a little microwave radiation, and about 75% of it is scattered by water vapor and oxygen.
• Radio waves-The sun emits radio waves least of all. Short radio waves (.1 to 10 meters) go right through our atmosphere. Long radio waves (10 m or more) are all scattered.

Overall, I'd say that about 30 to 40% of the sun's radiation is scattered by our atmosphere.