Jinqiao Duan, James Brannan, Vincent Ervin
Escape Probability, Mean Residence Time and
Geophysical Fluid Particle Dynamics
(1863K, Postscript)
ABSTRACT. Stochastic dynamical systems arise as models for
fluid particle motion in geophysical flows with
random velocity fields. Escape probability (from a fluid domain) and mean
residence time (in a fluid domain) quantify
fluid transport between flow
regimes of different characteristic motion.
We consider a quasigeostrophic meandering jet model with random
perturbations. This jet is parameterized by the
parameter $\beta = \frac{2 \Omega}{r} \cos (\theta)$, where
$\Omega$ is the rotation rate of the earth, $r$ the earth's radius and $\theta$
the latitude. Note that $\Omega$ and $r$ are fixed, so $\beta$ is a monotonic
decreasing function of the latitude. The unperturbed jet
(for $0 < \beta <\frac23$)
consists of a basic flow with attached eddies.
With random perturbations, there is
fluid exchange between regimes of different characteristic motion.
We quantify the exchange by escape probability and mean residence time.