Anders Lindroth¹, Jutta Holst², Mika Aurela³, Michal Heliasz², Jinshu Chi⁴, Andreas Ibrom⁵, Pasi Kolari⁶, Leif Klemedtsson⁷, Tuomas J A Laurila⁸, Maj-Lena Linderson⁹, Ivan Mammarella¹⁰, Meelis Mölder¹, Matthias Peichl¹¹, Kim Pilegaard¹², Timo Vesala¹⁰, Per Weslien¹³ and Patrik Vestin⁹, (1)Lund University, Department of Physical Geography and Ecosystem Science, Lund, Sweden, (2)Lund University, Physical Geography and Ecosystem Sciences, Lund, Sweden, (3)Finnish Meteorological Institute, Helsinki, Finland, (4)Swedish University of Agricultural Sciences, Umeå, Sweden, (5)Technical University of Denmark, Department of Environmental Engineering, Copenhagen, Denmark, (6)University of Helsinki, Helsinki, Finland, (7)University of Gothenburg, Gothenburg, Sweden, (8)Finnish Meteorological Inst, Helsinki 76, Finland, (9)Lund University, Lund, Sweden, (10)University of Helsinki, Institute for Atmospheric and Earth System Research / Physics, Faculty of Science, Helsinki, Finland, (11)SLU Swedish University of Agricultural Sciences Umeå, Department of Forest Ecology and Management, Umeå, Sweden, (12)Technical University of Denmark, Lyngby, Denmark, (13)University of Gothenburg, Department of Earth Sciences, Gothenburg, Sweden