The fractal dimension of drifter trajectories and estimates of horizontal eddy-diffusivity

Abstract

We analyze drifter data from the Northeast Atlantic and find that single-particle motion has fractal dimension D = 1.28 ± 0.08 at scales 5 to 100 km. The single particle trajectories are modeled using fractional Brownian motion. Integral time scale is therefore shown to be a function of both the time between position fixes and the length of the total period the drifter was tracked. The variance (particle dispersion) grows as approximately t3/2. The probability density function of single-particle velocity is observed to be leptokurtic, consistent with the fractional Brownian motion model. -from Authors