Energy and potential enstrophy flux constraints in the two-layer quasi-geostrophic model

Abstract

We investigate an inequality constraining the energy and potential enstrophy flux in the two-layer quasi-geostrophic model. This flux inequality is unconditionally satisfied for the case of two-dimensional Navier-Stokes turbulence. However, it is not obvious that it remains valid under the multi-layer quasi-geostrophic model. The physical significance of this inequality is that it decides whether any given model can reproduce the Nastrom-Gage spectrum of the atmosphere, at least in terms of the total energy spectrum. We derive the general form of the energy and potential enstrophy dissipation rate spectra for a generalized multi-layer model. We then specialize these results for the case of the two-layer quasi-geostrophic model under dissipation configurations in which the dissipation terms for each layer are dependent only on the streamfunction or potential vorticity of that layer. We derive sufficient conditions for satisfying the flux inequality and discuss the possibility of violating it under different conditions.