1. Department of Arctic GeophysicsThe University Centre in Svalbard Longyearbyen Norway
2. Department of Physics and TechnologyUniversity of Tromsø Tromsø Norway
3. Space and Earth Observation CentreFinnish Meteorological Institute Helsinki Finland
4. Sodankylä Geophysical ObservatoryUniversity of Oulu Sodankylä Finland
5. Birkeland Centre for Space Science Bergen Norway