Distribution of sodium in the daytime upper atmosphere as measured by a rocket experiment

The distribution of free atomic sodium was measured with a rocket-borne day airglow photometer above Wallops Island, Virginia, on September 26, 1964. The sodium was concentrated in a thin layer 5 km wide at 92.4 km. There were 16 × 109 atoms cm−2 compared to 6.2 × 109 atoms cm−2 at 89 km during the preceding twilight. The distribution found is not compatible with a purely photochemical theory. A thin layer source is required at 92.4 km. A theory is developed of layer formation involving sodium atoms liberated from an aerosol layer, diffusing away from it, and reacting chemically with ozone. The radiative transfer theory supporting the analysis of the experiment is developed in detail.