Evidence for turbopause control on neutral density variations in the lower thermosphere

Abstract

Data obtained from in situ neutral composition measurements over the dip equator are used in explaining the altitude variation of relative composition. The turbopause height (h₁) and the model exospheric temperatures (T_∞) are used in explaining the altitude variation of [O₂]/[N₂]. Although the measured [O₂]/[N₂] ratio at any altitude in the lower thermosphere does not show any direct relation to either the exospheric temperature or the turbopause height, it shows a fairly linear relation to the product of h_t × T_∞ . This is clear evidence for the altitude distribution of the neutral species being controlled by the mutually independent variables, viz. the turbopause height and the exospheric temperature.