Improvement of Global Ionospheric TEC Derivation with Multi-Source Data in Modip Latitude

Global ionospheric total electron content (TEC) is generally derived with ground-based Navigation Satellite System (GNSS) observations based on mathematical models in a solar-geomagnetic reference frame. However, are not well-distributed. There lack of over sparsely populated areas and vast oceans, where the accuracy TEC derivation reduced. Additionally, modified dip (modip) latitude more suitable than geomagnetic for ionosphere. This paper investigates improvement global multi-source data modip latitude, simulation International Reference Ionosphere (IRI) model developed. Compared using mean was about 10.88% after addition space-based adoption latitude. Nevertheless, from JASON-2 satellite altimetry COSMIC occultation sparsely-sampled, which makes IRI reasonable estimation without observation. By ground-based, satellite-based IRI-produced observations, both latitudes 12 days four seasons 2014 under quiet conditions. The average root-mean-square error (RMSE) fitting reduced by 7.02% largest March smallest June.