When you are in an airplane with clouds well below you why do you encounter turbulence? One reason is internal gravity waves. These waves move vertically through the atmosphere and break within it. (The equivalent phenomena on the ocean surface would be crashing waves creating a surf). Researchers are examining how internal gravity waves are generated, propagate and break in order to understand their influence on the Earth's weather and climate. But many open questions remain unresolved, and some fundamental questions have not yet been asked.

This talk will review the physics and mathematical theory for small-amplitude internal gravity waves and will illustrate present limitations on our understanding through laboratory experiments and numerical simulations. The talk will focus on internal gravity wave transmission across a "mixed patch", a problem whose dynamics are mathematically equivalent to the quantum mechanical problem of electron transmission across a "potential barrier".

The material will be presented in a manner accessible to senior undergraduates and other nonspecialists of fluid dynamics