Importance of propagation effects in determining the characteristics of inertia-gravity waves generated by jets and fronts

It has been noted in observations and in numerical simulations that large amplitude gravity waves in the vicinity of jets are often located in jet exit regions. These waves are propagating in a complex, three-dimensional, time-evolving flow. How this propagation may influence the characteristics of the gravity waves, whatever the generating mechanism, is the object of this study.

As a simpler example, we first investigate the propagation and evolution of gravity waves in the exit region of a balanced, steadily propagating dipole. Simple ray-tracing considerations and numerical simulations suggest that this background flow may have a systematic effect on the evolution of the characteristics of the gravity waves. Full simulations of baroclinic lifecycles, using the Weather Research and Forecast Model, are then used to establish the importance of these effects in more realistic flows.