Estimates of ionosphere state over Mexico with TEC data

The ionosphere behaviour over Mexico was studied. We analysed variations of Total Electron Content (TEC) and critical frequency of F2-layer of the ionosphere (foF2). TEC values were extracted from data of local GNSS receivers and if missed then from global ionospheric maps. foF2 values were reconstructed using TEC measured over Mexico and equivalent slab thickness of the ionosphere measured in the adjacent to Mexico regions having ionosondes. Diurnal and seasonal patterns of TEC and foF2 behaviour over Mexico were revealed. The peculiarity of TEC behaviour during disturbances were studied. The presence of strong positive enhancements is a characteristic feature for Mexico that is confirmed by measurements of electron concentration at satellites CHAMP and DSMP.