Transport properties in the Adriatic Sea as deduced from drifter data

The surface transport properties in the Adriatic Sea, a semienclosed subbas in of the Mediterranean Sea, have been studied using a drifter dataset in t he period December 1994-March 1996. Three main points have been addressed. First, the exchange between southern and northern regions and between deep and coastal areas have been studied, focusing on the role of topography. A significant cross-topography or cross-shelf exchange has been found, probab ly due to the direct wind forcing and to the influence of stratification th at isolates the surface flow from bottom effects, especially in the open se a. Second, a Lagrangian transport model with parameters derived from the da ta has been implemented. Simulated particles have been compared with drifte r data with positive results. The model is found to be able to reproduce re ality with good approximation, except for a specific advective event during the late summer season. Finally, the residence timescale T, that is, the a verage time spent by a surface particle in the basin, has been estimated. D irect estimates from the data suggest T approximate to 70-90 days, but thes e values are biased due to the finite lifetime of the drifters. Model resul ts have been used to estimate the bias, and they suggest a "true" value of T approximate to 200 days.