CAS Seminar

Tuba Masur

(Jacobs University)

"Update on optimal balance for geophysical flows and spontaneous emission"

Date: Wed, March 13, 2019
Time: 15:45
Place: Research I Meeting Room

Abstract: Esentially balanced large-scale oceanic flows are broken down in small scales due to spontaneous emission of gravity waves, so-called imbalanced flows. This spontaneous emission is closely interlinked to a dissipation route of energy in the ocean, which is essential to understand ocean dynamics. To analyse the role of imbalanced flows in the energy transfer, decomposing geophysical flows into balanced and imbalanced components is required due to nonlinear coupling between the components. This flow decomposition can be provided by a pure numerical scheme optimal balance which is introduced by Viúdez and Dritschel (2004). This scheme is studied in the context of rapidly rotating fluid flow with Langrangian view to provide balanced initializations for geophysical flows. We aim to investigate this numerical scheme in the rotating shallow water model with primitive variables. In our scheme, the decomposition of balanced-imbalanced flows is carried out through adiabatically deforming the nonlinear rotating shallow water model into a linear one for which mode-splitting is exact, where this procedure is treated as a boundary value problem in time to be solved iteratively until converging a balanced flow. In the iterative procedure, we observe a fast convergence to a balanced flow and set a nearly-balanced initialization to the model. Then, we want to investigate excitation of imbalances through time evolution. In this talk, we will discuss on this on-going research starting with introduction of the numerical scheme, and then, discussion on parameter and some existing results will follow.