Abstract. A self-consistent method for day-time F2-region modelling was applied to the analysis of Millstone Hill incoherent scatter observations during the storm period of March 16-22, 1990. The method allows us to calculate in a self-consistent way neutral composition, temperature and meridional wind as well as the ionized species height distribution. Theoretically calculated x e (h) pro®les ®t the observed daytime ones with great accuracy in the whole range of heights above 150 km for both quiet and disturbed days. The overall increase in ex by 270 K from March 16 to March 22 re¯ects the increase of solar activity level during the period in question. A 30% decrease in [O] and a twofold increase in [x 2 ] are calculated for the disturbed day of March 22 relative to quiet time prestorm conditions. Only a small reaction to the ®rst geomagnetic disturbance on March 18 and the initial phase of the second storm on March 20 was found in [O] and [x 2 ] variations. The meridional neutral wind inferred from plasma vertical drift clearly demonstrates the dependence on the geomagnetic activity level being more equatorward on disturbed days. Small positive F2-layer storm e ects on March 18 and 20 are totally attributed to the decrease in the northward neutral wind but not to changes in neutral composition. A moderate (by a factor of 1.5) O/ x 2 ratio decrease relative to the MSIS-83 model prediction is required to describe the observed x m p 2 decrease on the most disturbed day of March 22, but virtually no change of this ratio is needed for March 21.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.