Investigation of Internal Wave Fields using Eulerian and Lagrangian Formulations

Our incomplete understanding of physical dissipation processes within an internal wave field impacts on question of mixing and momentum transport in both the atmosphere and ocean, with enormous dynamical ramifications in the case of the middle atmosphere. Efforts to solve the puzzle have centred on nonlinear interactions among internal gravity waves, but the inherent complexity has hindered progress. Some recent publications have proposed that the complexity could be circumvented by using a Lagrangian, rather than Eulerian, formulation. We investigate this proposition numerically, using equivalent nonlinear Eulerian and Lagrangian equations and wave fields typical of the middle atmosphere.