1. a Institute of Oceanography, University of Gdańsk , Gdańsk, Poland E-mail:
2. b Institute of Geography, Nicolaus Copernicus University , Toruń, Poland E-mail:
3. c Faculty of Geography and Regional Studies , University of Warsaw , Warsaw, Poland E-mail:
4. d Institute of Water Engineering and Water Management, Technical University of Cracow , Cracow, Poland E-mail:
5. e Research Centre for Agricultural and Forest Environment , Polish Academy of Sciences , Bukowska 19, 60-809, Poznań, Poland E-mail:
6. f Potsdam Institute for Climate Impact Research , Telegrafenberg, D-14412, Potsdam, Germany. E-mail: