A diurnal analysis of local NO3, variabilities is presented for selected atmospheric elements along the lines of sight which were observed by Noxon et al. (1978). In review of recent debates (Hermann, 1980; Noxon et al., 1980a) concerning alternative interpretations of these measurements, the present analysis indicates that current photochemical theory is consistent with the experimental observations of diurnal variations in total NO3. Furthermore, diurnal variations in trace species column densities are shown to be potentially very sensitive tests of photochemical mechanisms and of physical perturbations when requisite levels of spatial and temporal resolution are achieved in observations.