171-179In the present paper the response of ionospheric parameters- ion densities and ion temperature (H+, O+ and Ti) to a weak (30 July 1999) and a moderate (13 November 1999) geomagnetic storm (GS) at low latitude Indian region using observed and modelled values has been analyzed. The study has been carried out by using ROCSAT-1 satellite data over the region encompassed between 5-35ΒΊ geog N and 65-95ΒΊ geog E at an average altitude ~ 600 km. A comparative study has also been done with the IRI-2016 modelled values. The ionospheric plasma parameters have shown anomalous behaviour during disturbed days in comparison to the quiet days. For the weak GS, both the average O+ and H+ density have been increased by a factor of around 1.8 during disturbed and quiet days respectively as calculated by ROCSAT-1. For the moderate GS, the average O+ and H+ density has been increased by a factor of around 2.7 and 6.3 respectively during disturbed and quiet days respectively, as calculated by ROCSAT-1. And the least or negligible variation has been observed in Ti for both measured and modelled values during weak and moderate GS
