Observation of the diurnal variation of atmospheric ozone

Ozone densities in the stratosphere and mesosphere have been derived from broad‐band photometer measurements of Hartley band absorption of middle ultraviolet radiation. Seven rockets were launched during October–November 1979 from Wallops Island. Six rockets, each carrying one detector comprising two UV photometers, were launched at different times of the day. A seventh rocket, with three similar detectors each having three UV photometers, was launched at the time of a full moon and provided estimates of the nighttime ozone densities. Results from these rocket flights form a basis for investigating ozone diurnal variations. The number of flights provide greater statistical reliability for the ozone profiles than is generally afforded from in situ measurements with a single rocket. During the night, an enhancement in ozone densities occurred at altitudes above about 50 km. At 70 km, for example, the nighttime ozone was determined to be a factor of 6.4 greater than at sunset. In addition, these experiments suggest that near 40 km the magnitude of the ozone density at noon may be greater by 10–15% than the nighttime concentration.