Neutral gas composition measurements between 80 and 120 km

Abstract Atmospheric composition in the turbopause regime was determined by four rocket-borne mass spectrometers, which employed shock-freezing cryo-ion sources. Number densities of N 2 , O 2 , O, Ar and CO 2 are presented for these experiments. The results are compared with those of other rocket experiments taken from the literature. Ar/N 2 ratios are analyzed with respect to atmospheric turbulence. Magnitude and variability of atomic oxygen layer maximum density and layer content are discussed. Variations of O densities and simultaneous Ar/N 2 ratio changes are compared. Six CO 2 measurements are discussed in terms of CO 2 /N 2 ratios.