Heat Transfer in the Atmosphere

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Heat Transfer in the Atmosphere

 

the horizontal and vertical transport of heat in the atmosphere. Heat flows from hotter regions to cooler regions. The greater the temperature difference, the more intense the heat flow.

In general, the temperature in the troposphere decreases from the equator to the poles and, at each latitude, decreases with increasing height. As a consequence of heat transfer between latitudes, the atmosphere loses heat in the tropical and subtropical latitudes (latitudes up to 40° in the northern hemisphere) and gains heat in the higher latitudes. In addition, heat is transferred in a latitudinal direction as a result of the nonuniformity of the thermal properties of the underlying surface—for example, the difference in the thermal properties of the land and ocean. In vertical heat transfer, the heat flow is directed primarily upward from the earth’s surface.

Heat is transported in the atmosphere in the following ways: through convection (including advection), that is, through the horizontal and vertical transport of air; through radiation; through transfer by means of the evaporation of water and the condensation of water vapor; and, to an insignificant degree, through molecular heat conduction.

Horizontal convective (advective) heat transfer between northern and southern latitudes occurs through the meridional transport of air masses and amounts to about 1019 calories (cal) per day. Vertical convective heat transfer is due both to ordered vertical motions of air in the regions of cyclones and anticyclones and to turbulence. The average vertical heat flow due to convective heat transfer in the northern hemisphere is approximately 50 cal/cm2/day.

Radiative heat transfer occurs through the absorption and emission of long-wavelength radiation by water vapor, dust, carbon dioxide, clouds, and other gases and aerosols in the atmosphere. Radiative heat transfer ultimately leads to the transfer of heat from the atmosphere into space. The average amount of heat radiated into space is 400 cal/cm2/day. In general, the heat loss to outer space decreases from low to high latitudes.

The average amount of heat transferred from the earth’s surface to the atmosphere through evaporation and condensation is about 120 cal/cm2/day. Heat transfer by this mechanism is most intense in the low latitudes.

An annual and daily variation is observed in the rate of heat transfer because of the existence of annual and daily temperature changes and daily variations in wind speed.

REFERENCES

Palmen, E., and C. Newton. Tsirkuliatsionnye sistemy atmosfery. Leningrad, 1973. (Translated from English.)
Khrgian, A. Kh. Fizika atmosfery. Leningrad, 1969.
Kondrat’ev, K. Ia. Luchistyi teploobmen v atmosfere. Leningrad, 1956.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.