Temperature Inversion

temperature inversion

[′tem·prə·chər in‚vər·zhən]

(meteorology)

A layer in the atmosphere in which temperature increases with altitude; the principal characteristic of an inversion layer is its marked static stability, so that very little turbulent exchange can occur within it; strong wind shears often occur across inversion layers, and abrupt changes in concentrations of atmospheric particulates and atmospheric water vapor may be encountered on ascending through the inversion layer. Also known as thermal inversion.

(oceanography)

A layer of a large body of water in which temperature increases with depth.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

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 It might be outdated or ideologically biased.

Temperature Inversion

 

an increase in air temperature with increasing altitude, which is inverse to the usual decrease in temperature with altitude in the troposphere. Temperature inversions occur both near the earth’s surface (ground temperature inversions) and in the free atmosphere. Ground inversions usually form on windless nights (sometimes also during the day in winter) as a result of the intensive radiation of heat by the earth’s surface, which cools the surface itself and the adjacent layer of air. Ground inversions measure dozens and hundreds of meters thick. The increase of temperature in the inversion layer varies from tenths of a degree to more than 15°-20°C. Eastern Siberia and Antarctica have the most intense winter ground inversions. In the troposphere, above the surface layer, temperature inversions usually form in high-pressure areas owing to the sinking of air, which is accompanied by its compression and therefore heating (subsidence inversion). In the zones of atmospheric fronts, temperature inversions are created by warm air advected over the cold air beneath. In the upper layers of the atmosphere (the stratosphere, the mesosphere, and the thermosphere) temperature inversions occur as a result of the strong absorption of solar radiation. For example, at altitudes of from 20–30 to 50–60 km there is a temperature inversion related to the absorption of ultraviolet radiation of the sun by ozone. At the base of this layer the temperature ranges between — 50° and — 70°C, while at its upper boundary the temperature rises to between —10° and + 10°C. Intense temperature inversions begin at altitudes of 80–90 km and stretch for hundreds of kilometers upward; they are also caused by absorption of solar radiation.

Temperature inversions are barrier layers in the atmosphere. They obstruct the development of vertical air currents, and as a result water vapor, dust, and condensation nuclei accumulate beneath them. This leads to the formation of layers of haze, fog, and clouds. Mirages sometimes occur as a result of the anomalous refraction of light in temperature inversions. Atmospheric ducts, which promote long-distance propagation of radio waves, also form in temperature inversions.

REFERENCE

Khrgian, A. Kh. Fizika atmosfery. Leningrad, 1969.

S. M. SHMETER

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.