Waves, currents and sea level variations along the Letipea - Sillamäe coastal section of the Southern Gulf of Finland

Variations in the hydrodynamic conditions were studied on the basis of 336 days of measurements with a Doppler current profiler. With wave data as a calibration reference, a semi-empirical hindcast of wave parameters is presented in the fetch- limited near-shore area for the period 1966–2008. A resultant 4–6 cm s−1 westward current dominated along the coast. Occasional fast sub-surface westward currents under modest wind forcing, as well as asymmetrical vertical profiles for westward and eastward currents indicated the influence of upwelling-related baroclinic coastal jets. The average frequency of upwelling was estimated at 17%; some of the events were identified in near-homothermic winter conditions on the basis of salinity and multi-layer flow records. While the mean sea level trend at Narva-Jõesuu roughly approximated the global estimates for 1899–2009, the annual maximum sea level increase was 5–8 mm yr−1. Both mean and maximum wave heights declined as a result of decreasing winds from the north.