Development and implementation of an empirical ionosphere variability model Original Research Article

Spacecraft designers and operations personnel conducting space environment analysis for low Earth orbit missions require ionospheric specification and forecast models that provide not only average ionospheric plasma parameters for a given set of geophysical conditions but the statistical variations about the mean as well. This paper provides preliminary results from an effort to develop empirical plasma variability models intended for use with the International Reference Ionosphere model. An electron number density and temperature database is derived from historical spacecraft measurements. Comparing observations with the IRI-2001 model provides mean deviations from the model as well as the range of possible values that may correspond to a given IRI output. Incorporation of the statistical variations in software to be run with the IRI model is described. An application of a specialized prototype variability model is described where the worst-case sunrise and daytime electron temperature and density values required for estimates of spacecraft charging in low Earth orbit are obtained from the variability model.