Global atomic oxygen density derived from OGO-6 1304 A airglow measurements

Results are presented for analysis of data on the atomic oxygen 1304-A triplet in the earth's dayglow between 400 and 1100 km which were obtained with the OGO-6 UV photometer during a 40-day period that included both quiet and disturbed conditions. Variations in the atomic oxygen column density are analyzed by obtaining best-fit models in which the 1304-A emission is produced by solar resonance scattering and photoelectron excitation. It is shown that the column density can be determined uniquely from the measured 1304-A intensity, provided the excitation processes can be described quantitatively. The values of the excitation parameters are determined directly from the data, and the deduced variations in column density over the daytime atmosphere are found to agree well with the Jacchia (1971) models. The latitudinal dependence of the column-density variations during a geomagnetic storm are discussed, the results are compared with recent measurements of the solar 1304-A fluxes as well as with calculations of the photoelectron excitation, and a method is suggested for determining the absolute atomic oxygen densities.