A stochastically excited linear system as a model for quasigeostrophic turbulence: analytic results for one- and two-layer fluids

Abstract

The authors explore the hypothesis that nonlinear eddy interactions in quasigeostrophic turbulence can be parameterized as a stochastic excitation plus an augmented dissipation in a statistically stationary equilibrium. The focus is primarily on models sufficiently simple to be solved analytically. In particular, closed form solutions are obtained for the linear response to stochastic excitation of horizontally uniform barotropic and two-layer baroclinic flow. The response of the barotropic model is very simple to understand because the governing equations are mathematically normal. In contrast, the two-layer model is non-normal in the presence of vertical shear and/or vertically asymmetric dissipation and yields rather complicated results. -from Authors