The UV dayglow 2, Lyα and Lyβ emissions and the H distribution in the mesosphere and thermosphere

Rocket observations of the Lyman α and Lyman β day airglow are analyzed using a nonisothermal spherical model of the radiation field. This new model provides, for the first time, a method of determining atomic hydrogen densities in the mesosphere and thermosphere. Interpretation of Lyman α data taken between 80 and 260 km is consistent with current mesospheric and thermospheric models, with H density equal to 1.9 × 10 7 cm −3 at 100 km. Analysis of 1025A data suggests that the emission is dominated by Lyman β with perhaps as much as a 30% contribution from OI 1027.