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) of the ionosphere on regional/global scale. Using permanent operating GPS ground station networks (e.g. that from IGS) the derived TEC maps may contribute to monitor the actual development of large scale structures in electron content and their dynamics during ionospheric perturbations (e.g.www.kn.nz.dlr.de/ → Ionosphere Impact → Storm). Based on GPS measurements at European IGS ground stations and subsequent TEC estimations and mapping, both individual as well as common features of ionospheric storms shall be discussed 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 structures (e.g. ionospheric response of solar eclipse on 11 August 1999). Detected TEC-perturbations are closely related to space weather characterizing quantities such as solar radio emission, solar wind and geomagnetic activity indices. Due to close relationships between TEC and space weather parameters a permanent space weather monitoring can help to control the ionospheric impact on operational navigation satellite systems.