Parameterization of dispersion in two-dimensional turbulence

We investigate the performance of standard stochastic models of single-part icle dispersion in two-dimensional turbulence. Owing to the presence of coh erent vortices, particle dispersion in two-dimensional turbulence is charac terized by a non-Gaussian velocity distribution and a non-exponential veloc ity autocorrelation, and it cannot be properly captured by either linear or nonlinear stochastic models with a single component process. Based on phys ical and dynamical considerations, we introduce a family of two-process sto chastic models that provide a better parameterization of turbulent dispersi on in rotating barotropic flows.