Definition
An atmospheric condition in which temperature increases with altitude instead of decreasing. The warmer air sits above cooler air near the surface, reversing the normal vertical temperature pattern. Inversions can bend or trap radar and radio signals, causing radar returns to display targets at incorrect ranges or to miss targets entirely.
Plain English
Normally, the air gets colder as you go up. In a temperature inversion, it gets warmer as you go up for a while. This flipped layer can bend radar beams in unexpected ways, so the radar picture may show things in the wrong place or not at all.
Context Anchor
Seen in discussions of radar limitations, especially when weather or atmospheric conditions affect how well ground-based radar can detect aircraft.
Derivation
From Latin 'invertere,' meaning 'to turn upside down.' The temperature profile is literally turned upside down compared to the usual pattern, which is a useful image to keep in mind.
Why Pilots Care
These layers can produce false radar returns or allow detection of distant targets, affecting navigation accuracy and traffic awareness.
Grounding Statement
Picture a warm lid of air sitting on top of a layer of cooler air near the ground -- the usual cold-on-top arrangement is flipped.
Intuition Check
A temperature inversion does not mean the temperature simply changes with height. It means the usual pattern is reversed: the air gets warmer as you go up through that layer.
Example Sentence 1
The controller mentioned that a temperature inversion over the area might be affecting radar returns at low altitudes.
Example Sentence 2
The briefing warned of temperature inversions that could extend radar coverage and create false targets.