Spatio-temporal variations in hydro-physical and -chemical parameters during a major upwelling event off the Southern coast of the Gulf of Finland in summer 2006

The objective of the paper is to document and examine the major upwelling event that occurred along the northern coast of Estonia in August 2006. With a horizontal extension of 360 km, the event was caused by persistent easterlies and was noticed by a large number of holidaymakers, as it reduced the temperature of the coastal sea to a chilly 5–10◦C for about a month. In situ measurements from an RDCP current profiler revealed an along-wind coastal jet of up to 60 cm s−1 and a weak near-bottom countercurrent. The depths of the pycnocline and nutricline rose. The maximum drop in water temperature was 16◦C, that of salinity was 3.6 PSU. Analysis of satellite images confirmed the large extension and the prominence of the event.