Department of Meteorology, Stockholm University, Stockholm, 10691 Sweden
Department of Meteorology, Stockholm University, Stockholm, 10691 Sweden; Leibniz Institute of Atmospheric Physics, Schlossstr. 6, Kühlungsborn, 18225 Germany
E.O. Hulbert Center for Space Research, Naval Research Laboratory, Washington, DC 20375, USA
Department of Meteorology, Stockholm University, Stockholm, 10691 Sweden