The single-particle dispersion, Lagrangian structure functions and Lagrangian energy spectra characteristic of two-dimensional incompressible turbulent flows are investigated theoretically and numerically. The domain of validity of the classical asymptotic estimates is extended; it is shown in particular that the asymptotic behavior of the single-particle dispersion at small times remains valid throughout the whole self-similar range when the Lagrangian energy spectrum is steeper than −1. Straightforward estimates of the Lagrangian integral time scale TL and the diffusion coefficient at large times K, based on energy and enstrophy, are proposed; to some extent, they remain valid locally, which allows an analysis of the spatial variability of TL and K within a single turbulent field. Finally, the detrimental effect of artificial numerical diffusion on the numerical simulation of Lagrangian statistics is highlighted and discussed.
The Journal of Marine Research publishes peer-reviewed research articles covering a broad array of topics in physical, biological and chemical oceanography. Articles that deal with processes, as well as those that report significant observations, are welcome. In the area of biology, studies involving coupling between ecological and physical processes are preferred over those that report systematics. Authors benefit from thorough reviews of their manuscripts, where an attempt is made to maximize clarity. The time between submission and publication is kept to a minimum; there is no page charge.