[1] Univ Helsinki, Dept Geosci & Geog, FIN-00014 Helsinki, Finland
[2] Lund Univ, Dept Phys Geog & Ecosyst Sci, Solvegatan 12, S-22362 Lund, Sweden
[3] Univ Innsbruck, Inst Atmospher & Cryospher Sci, A-6020 Innsbruck, Austria
[4] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA