What kinds of radiation pass through the atmosphere, and what kinds are absorbed?
A. Visible radiation ranges from about 0.35 to about 0.75 micrometers in wavelength. Very little visible radiation is absorbed by gases in the atmosphere. About 30-31 percent of incoming solar radiation is reflected and about 19 percent more is absorbed, mostly by clouds and particulate matter rather than by carbon dioxide and water vapor and oxygen. Those gases absorb a small amount of visible light, but not much. This is in contrast to the infrared (wavelengths greater than about 0.75 micrometer) radiation emitted by the earth’s surface. This radiation has wavelengths mostly between about 2 and 20 micrometers and over 90% of it is absorbed by water vapor, carbon dioxide, methane, ozone, nitrous oxide, fluorocarbons, and other radiatively active (“greenhouse”) gases on the way up. Radiatively active gases are active in specific wavelengths of radiation. For example, if we could see in the infrared spectrum between 5 and 8 micrometers, we could not see the earth’s surface (even on a cl
