Evridiki Chrysagi, University of Hamburg, Hamburg, Germany, Lars Umlauf, Leibniz Institute for Baltic Sea Research (IOW), Rostock-Warnemuende, Germany, Ulf Gräwe, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany, Hans Burchard, Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany and Alberto Naveira Garabato, University of Southampton, School of Ocean and Earth Science, Southampton, United Kingdom