Performance evaluation of global ionospheric models with indian regional navigation data over low latitude station during low solar activity year 2017

This paper discusses the variation of ionospheric Total Electron Content (TEC) over low latitude Indian region, Hyderabad station (Lat: 17.39◦ N, Lon: 78.31◦ E) for geomagnetic quiet and disturbed days during the low solar activity period (2017 year) of the 24th solar cycle using global ionospheric models and experimental NavIC (Navigation with Indian Constellation) data. The work mainly focuses on the performance of the IRI Plas 2017 (International Reference Ionosphere) model with and without assimilation of TEC input, GIM TEC (Global Ionospheric Maps) and IRI 2016 models. In order to evaluate the performance of the models, the diurnal, monthly, and seasonal variations of Vertical TEC (VTEC) are predicted and compared with Indian regional NavIC data. From the result analysis it is observed that smaller Root Mean Square Errors (RMSEs) between NavIC VTEC and modelled VTEC are found in June and December solstice months than March and September equinox months. The VTEC predicted by the IRI Plas with assimilation of TEC input option produced smaller estimation errors than IRI Plas without assimilation of TEC input and IRI 2016 model. The same analysis has been tested for geomagnetic storm occurred during 7–9 September, 2017 for different locations. The IRI Plas 2017 with TEC input option exhibits better performance than IRI Plas and IRI 2016 models. Therefore, the VTEC predictions by assimilation of optional inputs will be helpful in applications of ionspheric studies to predict the dynamics in the ionosphere particularly for the period of disturbed geomagnetic conditions. © 2021, Electromagnetics Academy. All rights reserved.