Ionospheric TEC Weather Map Over South America

Abstract

Ionospheric weather maps using the total electron content (TEC) monitored by ground based GNSS receivers over South American continent, TECMAP, have been operationally produced by INPE´s Space Weather Study and Monitoring Program (Estudo e Monitoramento Brasileiro de Clima Especial, EMBRACE) since 2013. In order to cover the whole continent, 4 GNSS receiver net-works, RBMC/IBGE, LISN, IGS and RAMSAC, in total ~140 sites, have been used. TECMAPs with a time resolution of 10 minutes are produced in 12 hour time delay. Spatial resolution of the map is rather low, varying between 50 and 500 km depending on the density of the observation points. Large day to day variabilities of the equatorial ionization anomaly (EIA) have been observed. Spatial gradient of TEC from the anomaly trough (TECu 80) causes a large ionospheric range delay in the GNSS positioning system. Ionospheric plasma bubbles (IPB), their seeding and development, could be monitored.These plasma density (spatial and temporal) variability causes not only the GNSS based positioning error but also radio wave scintillations. Monitoring of these phenomena by TEC Mapping becomes an important issue for Space Weather concern for high technology positioning system and telecommunication.