Dr. Robin Shelton is hosting Dr. John Knox of the University of Georgia this week and his talk is entitled "The Physics Behind Clear-Air Turbulence (CAT): An Unsolved Mystery."

Airplane passengers experience clear-air turbulence (CAT) when the flight becomes bumpy at high altitudes far away from thick clouds, thunderstorms, or other known sources of turbulence. Why does CAT happen, what are the physical processes leading to this phenomenon, and how can we forecast it better so pilots can avoid it? In this talk, I attempt to answer these surprisingly difficult questions in the context of fluid dynamics principles, specifically hydrodynamic instabilities and buoyancy waves in the atmosphere. I will present results from my own research collaboration with an experimental fluid dynamicist on a link between CAT and a recently discovered source of atmospheric buoyancy waves based on aeroacoustics research.