Observations of currents and temperature-salinity-pigment fields in the northern Adriatic Sea in winter 2003

Satellite (sea surface temperature and chlorophyll concentration) and in-situ data (currents from surface drifters and ADCP; sub-surface temperature, salinity and optical properties measured by a towed-vehicle) are used to describe the circulation features and the distribution of temperature, salinity and chlorophyll pigment in the northern Adriatic Sea in winter 2003, with particular focus on fronts and jets. The horizontal structure and temporal variations of these parameters are qualitatively related to the local wind forcing, to the river runoff and to the bathymetry. Vigorous currents are triggered by predominant northeasterly Bora wind events, including a strong cross-basin jet, south of Istria, associated with a sharp (> 3°C/km) and thin (< 0.5 km) front almost compensated in temperature and salinity and affected by barotropic instabilities. To the north, a cyclonic gyre is evident with a southern limb corresponding to the Po River plume extending offshore to the NE. Cold and pigment-rich, river-influenced waters prevail off the entire Italian coast. South of the Po delta these waters flow southeastwards in a coastal layer with baroclinic instabilities.