A Regional Ionospheric TEC Map Assimilation Method Considering Temporal Scale During Geomagnetic Storms

The temporal variations and spatial variations in the ionosphere during geomagnetic storms are exceptionally complex and drastic, significantly complicating ionospheric model construction. In this study, we present a multi-site, high-precision ionospheric vertical total electron content (VTEC) estimation method by constraining the VTEC when the locations of ionospheric pierce points (IPPs), determined by multiple sites, are nearby. The root mean square error (RMSE) relative to the global ionospheric map (GIM) VTEC is 3.22 TEC units (TECU), with a correlation coefficient of 0.98. This method enables the high-precision estimation of VTEC at IPPs. Utilizing the Gauss–Markov Kalman filter data assimilation algorithm, we consider the relationship between various Dst indices and the ionospheric temporal scales, achieving a regional ionospheric total electron content (TEC) Map during geomagnetic storms. This approach effectively monitors the impact of geomagnetic storms on the ionospheric total electron content (TEC) and provides a more accurate representation of ionospheric changes during geomagnetic storms compared to the GIM TEC Map and the International Reference Ionosphere (IRI)-2020 model.