Lagrangian covariance analysis of homogeneous -plane turbulence
نویسنده
چکیده
J. R. Ristorcelli X Division, Los Alamos National Laboratory University of California, Los Alamos, NM 87545 A.C. Poje Division of Applied Mathematics Brown University, Providence, RI 02192 Abstract The e ects of Rossby wave { turbulence interactions on particle dispersion are investigated in a Lagrangian analysis of the potential vorticity equation. The analysis produces several exact statistical results for uid particle dispersion in barotropic turbulence on a plane. In the inviscid problem the rst integral time scale of the meriodional velocity is found to be zero and the meridional particle dispersion is bounded. The second integral time scale, which determines the magnitude of the bound, is shown to depend explicitly on , the enstrophy and the energy of the meridional velocity. Expressions relating the autocorrelation of the vorticity to the autocorrelation of the meridional velocity are also derived and the Lagrangian integral time scale of the relative vorticity is diagnostically related to the meridional velocity correlation. The applicability of these predictions is veri ed in a series of numerical simulations. For a range of values, the meridional extent of quasi-steady alternating zonal jets occurring in the numerical solutions scales with a length scale given by the the standard deviation of the meridional particle dispersion.
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