Latitudinal variations of solar flux dependence in the topside plasma density: comparison between IRI model and observations

Abstract

The solar flux variations of plasma density in the topside ionosphere around 1000 km altitude at lower and higher latitudes are compared using the satellite data and the International Reference Ionosphere (IRI) model. The modeled profiles show rather stronger dependence on the solar activity at higher latitudes than at lower latitudes. These strong latitudinal variations are not seen in the observed data. Comparison with ISS-b data has shown that the IRI model gives systematically greater topside electron density at higher latitude. In an average sense the IRI model overestimates the high latitude electron density at 1100 km altitude by about a factor of 5 than the observations during high solar activity periods.