Abstract

Introduction: Ionospheric modelling is very crucial in ionospheric studies because of paucity in data in regions where ionospheric instruments such as Global Positioning System (GPS) receivers, ionosonde/digisonde, etc., are hardly available. Aim: In this research, the assessment of GPS-TEC using three ionospheric models namely: IRI-2016, IRI-Plas2017 and NeQuick-2 models in the Australian longitude sector (DAV1) for the period of 2011 – 2017 was studied. Materials and Methods: Hourly mean values of Total Electron Content (TEC) obtained from the GPS receiver at DAV1 station, and some ionospheric models were used to analyze the diurnal and seasonal variations in TEC. The prediction capability of the ionospheric models using annual Root Mean Square Errors (RMSE) and annual Mean Absolute Errors (MAE) between GPS-TEC and the ionospheric models were used to assess the performances of the ionospheric models. Results: Results obtained shows highest TEC values (~42 TECU) around 5:00UT corresponding to noontime (12:00LT) and at 09:00UT corresponding to post-noon (14:00LT) hours while lowest TEC values ~2 TECU were recorded at 18:00UT (01:00LT) and at 22:00UT (05:00LT) hours of the day. The results also show higher TEC values during the equinoxes than the solstices, except for the December solstice which recorded almost equal magnitude of TEC values as observed in the equinoxes. Conclusion: Generally, this study shows that the IRI-Plas 2017 model had better performance than both the IRI-2016 the NeQuick-2 models throughout the study period, showing least RMSE and MAE values in most seasons.

Keywords: NeQuick, IRI-2016, and IRI-Plas2017