Inversion – The Wise Pilot

A temperature inversion is a reversal of the normal behaviour of temperature in the troposphere (the region of the atmosphere nearest Earth’s surface), in which a layer of cool air at the surface is overlain by a layer of warmer air.

Glossary: Clear Air Turbulence
Clear Air Turbulence (CAT) is defined as sudden severe turbulence occurring in cloudless regions that causes violent buffeting of aircraft. This term is commonly applied to higher altitude turbulence associated with wind shear.