Relative dispersion in the Liguro-Provençal basin: From sub-mesoscale to mesoscale

摘要: Abstract Relative dispersion in the Liguro-Provencal basin (a subregion of Mediterranean Sea) is investigated using clusters surface drifters deployed during two Marine Rapid Environment Assessment (MREA) experiments covering different months 2007 and 2008, respectively. The have initial radii less than 1 km, or an order magnitude below a typical deformation radius (approximately 10–20 km). data set consists 45 original pairs more 50 total (including chance ones) spatial range between 1 200 km. estimated mean square separation particle Finite Scale Lyapunov Exponents (FSLEs). metrics show broadly consistent results, indicating particular clear exponential behaviour with e-folding time scale 0.5 days, exponent λ 0.7–1 days−1. phase extends for 4–7 days 10–20 km space. To our knowledge, this only third that regime observed world ocean from drifter data. This result suggests relative nonlocal, namely controlled mainly by mesoscale dynamics, effects sub-mesoscale motions are negligible comparison. NCOM model results used to complement quantify errors arising sparse sampling observations.