On dispersion properties of surface motions in the Gulf of Finland; pp. 269–279

Abstract

The spreading rate of initially closely located water particles and passive drifters in the surface layer of the Gulf of Finland is studied using autonomous surface drifters. The average spreading rate increases with the increase in the time elapsed from the deployment, equivalently, with the increase in the distance between drifters. The typical spreading rate is about 200 m/day for separations below 0.5 km, 500 m/day for separations below 1 km and in the range of 0.5–3 km/day for separations in the range of 1–4 km. The spreading rate does not follow the Richardson law. The initial spreading, up to a distance of about 150 m, is governed by the power law d ~ t 0.27 whereas for larger separations the distance increases as d ~ t 2.5.