temperature inversion

Noun

temperature inversion (plural temperature inversions)

1. An atmospheric condition in which a cooler layer of air lies below a warmer layer of air that functions as a "ceiling" for the cooler layer, interfering with normal atmospheric circulation and trapping pollutants.
   • Temperature inversions can occur in perfectly clear skies. Samford said such an inversion was present in the Washington area early last Sunday, when up to a dozen unidentified flying objects appeared on radar screens both at Washington national airport and nearby Andrews air base.1952 July 30, Vern Haugland (Associated Press), "Air Force Says Saucers No Menace to US", Ludington Daily News (Michigan, USA), p. 1 (Retrieved 21 June 2012)
   • It's possible that a temperature inversion—a layer of warm air lying on top of a layer of cold air—is causing the sounds of the sonic booms to be carried inland, he said.1993 March 6, Linda Hetsel, “Jets over Gulf may have caused booms”, in Victoria Advocate, Texas, USA, retrieved 21 Jun 2012, page 12A