Evaluation of the ion-density measurements by the Indian satellite SROSS-C2

Abstract

[1] The ion and electron F region plasma measurements made by the ion and electron Retarding Potential Analyzers (RPAs) onboard the Indian satellite SROSS-C2, have yielded excellent data set over the Indian region for more than half a solar cycle, after the SROSS-C2 launch in May 1994. The absolute ion density, ion temperature, and ion composition parameters are derived from these in situ measurements and used by many workers. In this paper the absolute values of ion density derived from the ion RPA measurements are compared and evaluated with the measurements made by ground-based ionosondes located in the Indian region and close to the SROSS-C2 orbital path. It is shown that a slight adjustment in efficiency factor of the ion RPA sensor brings the in situ measurements much closer to those obtained from the ground-based ionosonde measurements taking into account the model calculations. It may be mentioned that this is a correction to the ion density measurement by SROSS-C2 by a fixed proportion (14-11.4%). The effect of change in efficiency factor on the ion current, which is used to deduce the ion number density, is demonstrated and discussed.

Equinoctial asymmetry in low latitude ionosphere as observed by SROSS-C2 satellite

“…for about 80 km in space there are no data points and again some data points with 170 m interval and so on (Garg et al, 2003). Recently, Subrahmanyam et al (2010) compared the ion density measured by SROSS C2 with the ground-based measurements and suggested a correction of 14-11.4% to the SROSS C2 measurements.…”

Space Weather Research: Indian perspective

“…In fact, most of the airglow measurements of terrestrial atmosphere have come from PRL [ Sridharan et al ., ]. The National Physical Laboratory added to the existing thermospheric‐ionospheric understanding through SROSS‐C2‐based measurements and efforts made in the direction of regional ionospheric modeling [ Subrahmanyam et al ., , and references therein]. The ground chain of magnetometers across the country maintained by the Indian Institute of Geomagnetism led to the fundamental understanding of the ionospheric current systems and their variability during active space weather conditions.…”