Ionospheric estimates of atomic oxygen concentration from charged particle measurements

Abstract

Radar backscatter and the rocket probe measurements of electron and ion temperatures and electron concentration are used to solve the thermal energy equation for the O⁺ ions. By equating the heat gained by the O⁺ ions from the hotter thermal electrons to the heat lost to the cooler neutrals, the concentration of the oxygen atoms n(O) is deduced. Significant seasonal changes in n(O) are identified. The calculated values of oxygen concentration are found to be consistently smaller than the Cira (1965) values throughout the latest rising, phase (1964-1967) of solar activity. This disagreement is greatest at low solar activity and reduces with the increase in activity. There is, however, general agreement on the time of diurnal maximum of n(O) between the calculated and model values.