[en] The use of optical measurements of the aurora and airglow to remotely sense the atmosphere are briefly described. It is shown that observations of the molecular oxygen emissions in the airglow require a peak atomic oxygen concentration of about 1.E12 cm-3. It is suggested that these emissions are excited in a two step process similar to the Barth mechanism for the green line. It is proposed that monitoring of the green line and the atmospheric bands will allow the atomic oxygen concentration in the lower thermosphere to be determined under both auroral and non-auroral conditions. (orig.)

[en] Recent laboratory measurements of the deactivation rate constants for 0(¹S) have suggested that the dominant production mechanism for the green line in the nightglow is a two-step process. A similar mechanism involving energy transfer from an excited state of molecular oxygen is considered as a potential source of the 01 (5577 A) emission in the aurora. It is shown that the mechanism 0₂ + e → 0₂* + e and 0₂* + 0 →0₂ + 0(¹S), is consistent with auroral observations; the intermediate excited state has been tentatively identified as the 0₂(c¹Σsub(u)^-) state. For the proposed energy transfer mechanism to be the primary source of the auroral green line, the peak electron impact cross-section for 0₂* production must be approximately 2 x 10^-17 cm². (author)

[en] The altitude distribution of the oxygen infrared atmospheric bands at 1.27 μm was measured during the total solar eclipse of 26 February 1979. The ozone concentration profile has been derived from these airglow measurements and indicates that at 85 km the concentration at totality was 7 x 1.7 cm^-3, with no well defined upper layer. This reduced concentration, which is typical of summertime conditions, was probably due to perturbations in the mesospheric chemistry and transport induced by a winter warming event that was in progress at the time of the eclipse. At 60 km the ozone concentration, 2.7 x 10¹⁰ cm^-3, was enhanced above that normally measured. This increase may also have been caused by the stratospheric warming event but the effects of a particle precipitation event, which was also in progress during the eclipse, may be important. (author)

[en] Rocket measurements of the O(sup(1)S-sup(1)D) 557.7-nm and Nsub(2)sup(+) (Bsup(2)Σsub(u)sup(+)-Xsup(2)Σsub(g)sup(+)) (0-0) 391.4-nm emission profiles for the steady component of an international brightness coefficient 1sup(+) aurora, which exhibited irregular pulsations, are presented. The Nsub(2)sup(+) volume emission profile is found to be in good agreement with theoretical profiles calculated from the primary-electron energy spectra recorded near apogee on the same flight. The O(sup(1)S) emission is found to increase with altitude relative to the Nsub(2)sup(+) emission between 100 and 130 km, and possible mechanisms for the excitation of O(sup(1)S) are examined. It is found that either energy transfer from Nsub(2)(Asup(3)Σsub(u)sup(+)) or the reaction of Nsup(+) with Osub(2) can explain most of the observed O(sup(1)S) emission, but the possibility of a different excitation mechanism cannot be ruled out

[en] Previous studies of photometric time sequences from pulsating aurora have established that the O(¹S) metastable leading to the emission of the auroral green line is excited by two processes, one direct, the other indirect, with the indirect precursor having a lifetime of about 0.1s. In this paper the authors report on new high time-resolution measurements which extend the observations of precursor lifetime down to about 0.01s. Simultaneous observations of pulsations in the Begard-Kaplan band system were also made in order to obtain direct measurements of the lifetimes of the N₂(A³Σ_u⁺) metastable; there were found to be essentially equal to those of the precursor over the lifetime range from 0.01s to 0.1s, and less well-correlated for longer lifetimes. This result identifies the O(¹S) precursor as N₂(A³Σ_u⁺), at least over the altitude range 97 to 125 km

[en] The WIND Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS) is a CCD imager which views a selection of airglow emissions at the limb through a field-widened Michelson interferometer. Winds are calculated from the Doppler shifts of the spectral lines, detected as changes in the phase of the fringes. WINDII has been operating in space for almost three years and its performance has been monitored over that time. It continues to function well, though subtle changes have been seen. This paper is a discussion of the endurance of the instrument and of the changes that have occurred during the mission

[en] Among the emissions viewed by the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS) are selected lines in the (0-0) transition of the O2 atmospheric band. These lines are viewed simultaneously using a narrow band filter/wide-angle Michelson interferometer combination. The narrow band filter is used to separate the lines on the CCD (spectral-spatial scanning) and the Michelson used to modulate the emissions so that winds and rotational temperatures may be measured from the Doppler shifts and relative intensities of the lines. In this report this technique will be outlined and the on-orbit behavior since launch summarized