MONITOR services SISTED and GSFLAI

The availability of extensive networks of Global Navigation Satellite Systems (GNSS) dual frequency receivers monitoring simultaneously the daylight and night hemispheres, makes it feasible to detect major solar flares as they cause rapid strong ionisation in the dayside ionosphere. This opportunity is used in the SISTED (Sunlit Ionosphere Sudden TEC Enhancement Detector) and GSFLAI (GNSS Solar Flare Indicator) products which have been developed and are operated by the Universitat Politècnica de Catalunya (UPC, Ionospheric determination and Navigation based on Satellite and Terrestrial systems). GSFLAI and SISTED are a part of the ESA MONITOR services (http://monitor.estec.esa.int). In collaboration with UPC, the Finnish Meteorological Institute (FMI) has integrated these services to the Ionospheric Weather Expert Service Centre which is operated under the ESA Space Situational Awareness Programme.