Latitudinal variations of TEC over Europe obtained from GPSobservations

Abstract
GPS technique has opened broad possibilities to study the TEC distribution on a regular basis. In this paper, the latitudinal dependence of TEC over Europe for geographic latitudes ranging from 40°N to 75°N is presented. We discuss the day-to-day variations of the latitudinal TEC profiles for a period of 1999 to 2001 for both quiet and disturbed magnetic conditions. More than 4300 TEC profiles were created from the TEC maps with a one-hour interval. GPS data from 65 European permanent stations were used to produce the TEC maps. The comparison of GPS-derived TEC profiles with the IRI model is also discussed. Key words. Ionosphere (mid-latitude ionosphere; ionospheric disturbances)