Diurnal variability of vibrationally excited mesospheric ozone as observed during the SPIRE Mission

Abstract

Spectrally resolved observations of infrared fluorescence (9–12 µm) from mesospheric ozone in the earth limb have been analyzed to deduce local excited vibrational state number densities as functions of altitude and solar illumination between 70 and 105 km. The nighttime and insolated quiescent polar atmospheres were sampled near the dawn terminator by a rocket‐borne cryogenic scanning filter spectrometer. Both the total intensity and the spectral distribution of the ozone fluorescence were observed to change after sunrise. The deduced vibrational populations revealed that this change was primarily due to a daytime reduction in the population of O3 (υ = 1), which is excited directly from ground state O3 by resonance absorption of earth radiation. In contrast, higher vibrational levels, formed by three‐body recombination of O and O2, show diurnal variations only at the lower altitudes, where the atomic oxygen concentration is expected to increase upon insolation. Thus the O3 (υ) fluorescence appears to be closely coupled to the local photochemical behavior of O and O3 near the mesopause.

Chemistry of vibrationally excited ozone in the upper atmosphere

“…This appears to occur in the case of the SPIRE dawn observations as discussed by Green et al [1985]. Major parameters to which the calculations are sensitive include the 03 density profile, the nascent distribution of O3(v) in the oxygen recombination reaction, and the O density profile.…”

“…These were estimated using the anharmonic oscillator/rigid rotor approximation developed for the analysis of COCHISE chemiluminescence data [Rawlins et al, 1981b] and subsequently used in analysis of HIRIS and SPIRE [Green et al, 1985] data. These were estimated using the anharmonic oscillator/rigid rotor approximation developed for the analysis of COCHISE chemiluminescence data [Rawlins et al, 1981b] and subsequently used in analysis of HIRIS and SPIRE [Green et al, 1985] data.…”

Vibrationally excited ozone in the middle atmosphere

“…Green et al (1986) analyzed SPIRE (Spectral Infrared Rocket Experiment) 9-12 mm atmospheric limb emission spectra indicating the existence of highly excited ozone vibrational states up to v 3 ¼ 6. A detailed analysis of SPIRE and HIRIS (High Resolution Interferometer Spectrometer) data with respect to the quasi-nascent distribution and the collisional relaxation model was carried out by Rawlins (1985).…”

Satellite observations of daytime and nighttime ozone in the mesosphere and lower thermosphere

“…Several rocket borne measurements of mesospheric ozone infrared emissions have been performed [e.g., Rawlins et al, 1985;Green et al, 1986;Grossmann and Vollmann, 1997]. Global upper mesospheric ozone infrared emission measurements have been analyzed by Zhou et al [1998] and Mill et al [1994].…”