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A measurement of hydroxyl in the daytime mesosphere

Thesis/Dissertation ·
OSTI ID:5832932
The objective of this thesis was the development of an instrument which would measure the concentration of hydroxyl in the mesosphere and an assessment, based on this data, of the current understanding of mesospheric chemistry. A new instrument, a coupled Ebert-Fastie spectrometer and Fabry-Perot interferometer (UV-FPI), was developed to measure spectroscopically the ultraviolet solar resonance fluorescence emission of hydroxyl. The instrument was designed to observe these emissions in the near-ultraviolet at 3087 {angstrom} against the bright background of Rayleigh scattered sunlight. The background was suppressed by the high resolution Fabry-Perot interferometer operating over the narrow wavelength region defined by the Ebert-Fastie spectrometer bandpass. The remote measurement of hydroxyl was made from a sounding rocket platform with the instrument viewing the earth's limb for the maximum integrated path length of hydroxyl emission. The sounding rocket payload also carried instrument which made simultaneous in situ and remote sensing measurements of atomic oxygen and temperature, respectively. Although the UV-FPI configuration was not optimum for measurement of the desired hydroxyl emission, upper limits could be set on the hydroxyl concentrations. They hydroxyl concentration inferred from the emission measurements was 50% lower than a previous measurement. Comparison of this result and the data for mesospheric abundances of ozone and atomic oxygen with current chemical models shows that modeled odd-hydrogen activity in the middle mesosphere must be increased in order to successfully model the chemical processes occurring in the mesosphere.
Research Organization:
Michigan Univ., Ann Arbor, MI (USA)
OSTI ID:
5832932
Country of Publication:
United States
Language:
English