- Radiative cooling
Radiative cooling is the condition in which a body loses more energy by radiation than it gains from its surroundings.
Meteorological effects
The large-scale circulation of the
Earth's atmosphere is driven by the difference in absorbed solar radiation per square meter, as the sun heats the Earth more in theTropics , mostly because of geometrical factors. The atmospheric and oceanic circulation redistributes some of this energy assensible heat andlatent heat partly via the mean flow and partly via eddies, known as cyclones in the atmosphere. Thus the tropics radiate less to space than they would if there were no circulation, and the poles radiate more; however in absolute terms the tropics radiate more energy to space.Personally experiencing radiative cooling
Radiative cooling is commonly experienced on cloudless nights, when heat is radiated into space from the surface of the Earth, or from the skin of a human observer. The effect is well-known among
amateur astronomers , and can personally be felt on the skin of an observer on a cloudless night. To feel the effect, one compares the difference between looking straight up into a cloudless night sky for several seconds, to that of placing a sheet of paper between one's face and the sky. Since outer space radiates at about a temperature of 3kelvin s (-270degrees Celsius or -450degrees Fahrenheit ), and the sheet of paper radiates at about 300 kelvins (room temperature), the sheet of paper radiates moreheat to one's face than does the darkened cosmos. The effect is blunted somewhat by Earth's surrounding atmosphere which also traps heat. Note that it is not correct to say that the sheet "blocks the cold" of the night sky; instead, the sheet is literally warming your face, just like a camp fire warms your face; the only difference is that a campfire is several hundred degrees warmer than a sheet of paper, just like a sheet of paper is several hundred degrees warmer than the deep night sky.
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