Analysis of ionospheric models during ionospheric disturbances

This paper describes an analysis of ionospheric models compared with real data during the occurrence of travelling ionospheric disturbances. GPS data was taken from Parit Raja Station (1deg 52´ N, 103deg 06´ E) in Southern Malaysia. Comparison was made from collected data during the geomagnetic quiet and storm days. Ionospheric models i.e. IRI2001, NeQuick and real data as in IONEX format were used in this study. Results were compared with real TEC data from Parit Raja as reference value, which was obtained from a general dual frequency method. Data collected from IONEX showed that the occurrence of TID was less frequent when compared to the real data from Parit Raja. This was due to the few ground stations located at site of study. For both the empirical models, IRI2001 and NeQuick, the predicted TEC was affected by the value of sunspot number and was suitable for geomagnetic quiet conditions. It is recommended that IRI and NeQuick models that undergo improvement should include ionospheric disturbances for more reliable TEC calculations.