Be able to describe what it means for the atmosphere to be a selective absorber. The atmosphere being a selective absorber means that it is not equally effective at absorbing different waveleght of radiation. be able to describe the atmospheric window. The range of wavelengths that are not readily absorbed by the gases of the atmosphere. (about 8 to 12 um). This is very important to radiation balance. given a wavelength of em radiation, be able to determine if the atmosphere would absorb it or not. Long wave radiation is absorbed by the atmosphere more readily than. Swr be able to describe the impact of clouds on the radiation budget. Day: during daylight hours clouds reduce the amount of swr that makes it to the earth"s surface, keeping temperatures cooler. Night: clouds readily absorb virtually all long wave radiation. This explains why cloudy nights do not cool off nearly.