TEC monitoring by GPS - A possible contribution to space weather monitoring

The world-wide use of GPS satellites for navigation and positioning offers a unique chance for permanent monitoring the total electron content (TEC) o f the ionosphere on regional/global scale, Using permanent operating GPS gr ound station networks (e.g. that from IGS) the derived TEC maps may contrib ute to monitor the actual development of large scale structures in electron content and their dynamics during ionospheric perturbations (e.g. www.kn.n z.dlr.de/ --> Ionosphere Impact --> Storm). Based on GPS measurements at Eu ropean IGS ground stations and subsequent TEC estimations and mapping, both individual as well as common features of ionospheric storms shall be discu ssed for the European ionosphere. The paper demonstrates the power of this new GPS tool to detect and to study the dynamics of large-scale spatial str uctures (e.g. ionospheric response of solar eclipse on I I August 1999). De tected TEC- perturbations are closely related to space weather characterizi ng quantities such as solar radio emission. solar wind and geomagnetic acti vity indices. Due to close relationships between TEC and space weather para meters a permanent space weather monitoring can help to control the ionosph eric impact on operational navigation satellite systems, (C) 2001 Elsevier Science Ltd. All rights reserved.