1. Service d'Aéronomie du CNRS/Institut Pierre-Simon Laplace (IPSL), BP.3, 91371, Verrières-le-Buisson, France.
2. Space Research Institute (IKI), 84/32 Profsoyuznaya, 117810 Moscow, Russia.
3. Laboratoire de Méteorologie Dynamique/IPSL, University Paris 6, 75252 Paris, France.
4. Belgian Institute for Space Aeronomy (BIRA), 3 Avenue Circulaire, B-1180 Brussels, Belgium.
5. Southwest Research Institute, Boulder, CO 80302, USA.