Evridiki Chrysagi, Leibniz Institute for Baltic Sea Research (IOW), Physical Oceanography, Warnemuende, Germany, Peter Ludwig Holtermann, Leibniz Institute for Baltic Sea Research (IOW), Rostock, Germany, Lars Umlauf, Leibniz Institute for Baltic Sea Research (IOW), Warnemuende, Germany and Hans Burchard, Leibniz Institute for Baltic Sea Research (IOW), Department for Physical Oceanography and Instrumentation, Rostock, Germany