Measurements of daytime ozone and O(¹D) concentrations in the mesosphere and lower thermosphere (MLT) have been derived from HRDI observations of the O₂ Atmospheric band emission. Over 5 years of ozone mixing ratios have been retrieved, covering all daylight local times and an altitude range of 65 to 97 km. HRDI measured ozone at the equator shows a predominantly semiannual variation at all altitudes, with up to a doubling of ozone at equinox. At mid-latitudes the variation is annual with a peak at winter solstice at 75 km, changing at summer solstice to 95 km. Good agreement is found between HRDI and HALOE ozone mesurements. In addition, below 80 km both datasets appear to show an anti-correlation between ozone concentrations and HALOE water vapor measurements.

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For more information email danielm@engin.umich.edu