Growth and nonlinear equilibration of baroclinic instability скачать в хорошем качестве

Growth and nonlinear equilibration of baroclinic instability

An initial value problem of the Philips 2-layer model for baroclinic instability (http://bit.ly/multilayerqg). Shown is the evolution of q (relative vorticity, ∂v/∂x-∂u/∂y, + vortex stretching term) for each layer. The flow starts form an small-amplitude random initial condition. Also shown is the evolution of the kinetic energy in each fluid layer KE₁(t), KE₂(t), and the potential energy at the fluid interface PE(t). Numerical details: domain size 2π x 2π; using a pseudo spectral solver with 256 x 256 grid points in each of the two layers; time-steped via a Runge-Kutta 4th-order scheme and time-step dt=0.001. The imposed zonal flow at the top layer is U₁=0.7 and at the bottom layer U₂=0.7. The fluid layer depths are H₁=0.2 and H₂=0.8. The bottom layer includes linear bottom drag with coefficient μ=0.05. The planetary vorticity gradient is β=25. The parameters chosen imply q₁ = ∇²ψ₁ + 225 (ψ₂-ψ₁) and q₂ = ∇²ψ₂ + 225/4 (ψ₁-ψ₂). The script used for this animation was largely based on the surface quasi-geostrophic example found in the documentation of GeophysicalFlows.jl at http://bit.ly/phillips2layer.