AERONOMY OF INFRARED OZONE FLUORESCENCE MEASURED DURING AN AURORA BY THE SPIRIT-1 ROCKET-BORNE INTERFEROMETER

The SPIRIT 1 rocket-borne infrared interferometer (4 to 25 mum) was launched from Poker Flat, Alaska, on April 8, 1986-, and viewed the atmosphere in full-limb and partial-limb geometries during nighttime IBC II-III auroral activity. Analysis of O3(nu3) fluorescence spectra (9 to 12 mum), obtained for tangent altitudes between 70 and 105 km, provides determinations of O3(upsilon) column density profiles for at least six quanta of O3 stretching vibration. Pure-rotation transitions from highly rotationally excited OH also contribute to the spectral intensities in this wavelength region. The observed ozone vibrational state populations are generally consistent with predictions of a nonauroral model describing atmospheric O3(upsilon) excitation in terms of earthshine absorption and three-body recombination of O and O2. In addition, discrepancies between full-limb and partial-limb results indicate an enhancement of O3(upsilon greater-than-or-equal-to 3) in the vicinity of a strong auroral arc, due to either a downward propagation of atomic oxygen near the aurora or a direct auroral excitation process. The derived O3(upsilon) number density profiles are used to estimate altitude profiles for total O3, O, and H and to examine the response of odd oxygen/odd hydrogen chemistry to auroral bombardment. The results illustrate the potential of spectrally resolved infrared fluorescence for remote sensing of high-altitude chemical responses on a global basis.