Low latitude ionospheric variations during geomagnetic storms measured using ROCSAT-1 satellite observations

Abstract

This paper studies the response of ionospheric parameters- ion densities (O⁺ and H⁺) and ion temperature (Ti) to a moderate (30 July 1999) and a strong (13 November 1999)  geomagnetic storm (GS) at low latitude Indian region using observations and modelling. The analysis has been carried out by using ROCSAT-1 satellite data over the region encompassed between 5-35º geog N and 65-95º geog E at an average altitude ~ 600 km. This study of the effect of these geomagnetic storms over the low-latitude F2 region ionosphere has been compared with the estimated values of IRI-2016 model. The ionospheric plasma parameters show anomalous behaviour during disturbed days compared to the quiet days. For the moderate GS, both the average O⁺ and H⁺ density are found to increase by a factor of around1.8 during disturbed and quiet days respectively as calculated by ROCSAT-1. For the strong GS, the average O⁺/H⁺ density is found to increase by a factor of around 2.7/ 6.3 respectively during disturbed/quiet days as calculated by ROCSAT-1. And the Ti is observed showing the least or negligible variation both by measured and modelled values during moderate and strong GS.