Division of Atmospheric Sciences, Department of Physical Sciences, University of Helsinki, Vourikatu 15 A, P.O. Box 503, Helsinki, 00101 Finland ; 2Nansen Environmental and Remote Sensing Centre / Bjerknes Centre for Climate Research, Thormohlensgate 47, Bergen, 5006 Norway
2Nansen Environmental and Remote Sensing Centre / Bjerknes Centre for Climate Research, Thormohlensgate 47, Bergen, 5006 Norway