Validation of IRI-2012 and NeQuick2 Derived TEC, NmF2, hmF2, B0, B1 and HT during the High Solar Activity over Brazilian Equatorial and Low Latitude sectors

Abstract:

The equatorial and low latitude ionosphere exhibits large variabilities in the electron density distribution owing to the presence of the dynamical phenomena such as the Equatorial Ionization Anomaly (EIA). In the presence of significant variabilities, accurate estimation of ionospheric Total Electron Content (TEC) has gained more importance in view of the communication and navigation applications. In the present study, the ionospheric electron density as well as the profile thickness and shape parameters have been compared simultaneously for understanding the performance of the latest available IRI-2012 and NeQuick2 models over the equatorial and low latitude sectors. The ground based ionosonde data in conjunction with the ROCSAT measured in-situ electron density in the topside ionosphere have been used to derive the vertical electron density profiles over three identified locations in the Brazilian equatorial and low latitude sectors during the high solar activity year of 2002. These reconstructed profiles are used to compare with the IRI-2012 and NeQuick2 models derived vertical electron density profiles. The diurnal and seasonal variations of TEC, F-layer peak density (N_mF₂), F-layer peak height (h_mF₂), bottom side thickness parameter (B0), shape parameter (B1) and topside effective scale height (H_T) have been studied to validate the IRI-2012 and NeQuick2 model simulations. It has been understand that these models underestimate the experimental TEC during day-time hours of the equinoctial and summer months of the high solar activity. The models show improved performance in the prediction of N_mF₂ and h_mF₂ compared to that of TEC during day-time hours. Further, it is observed that the IRI-2012 as well as the NeQuick2 models show considerable deviations in the estimation of the bottom side profile parameters while more discrepancies are observed in the prediction of topside effective scale height values particularly during day-time hours.