1. Department of Meteorology, University of Reading, Earley Gate, PO Box 243, Reading RG6 6BB, UK
2. V.E. Zuev Institute of Atmospheric Optics, SB RAS, 1, Academician Zuev Square, Tomsk 634021, Russia
3. RAL Space, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK