Finnish Forest Research Institute, Rovaniemi Northern Unit, 96300, Finland;
Training Centre of China Meteorological Administration, Beijing 100081, China;
Finnish Environment Institute, Helsinki P.O.Box 140, 00251, Finland;
Department of Geosciences and Geography, University of Helsinki, Helsinki P.O.Box 64, 00014, Finland;
Finnish Forest Research Institute, Rovaniemi Northern Unit, 96300, Finland;
