Status
The 1999 Leonid MAC campaign consisted of five consecutive nighttime flights including stops in the United States, England, Israel, and the Azores. The Space Dynamics Laboratory of Utah State University operated several instruments in the visible and infrared spectral bands. One system obtained high-resolution (4 cm-1) measurements of the night sky emission spectra in the 1 to 1.65-micrometer band. Measurements were obtained above the clouds providing exceptional viewing conditions. The OH airglow emission layer originates at an altitude of ~87 km and has a half-width of typically 8–10 km. Its behavior during the storm night of 17/18 November 1999 was of particular interest because the OH airglow emission may be affected by the Leonid meteor ablation products that can penetrate to altitudes as low as 80 to 90 km altitudes. Typical Leonid meteor end-heights are much higher above ~100 km. Variability of the OH emission was measured to investigate any changes that may result from meteor interactions with the atmosphere that could cause changes in the natural airglow emission via excitation caused by the meteor ablation products. It is also possible that organic materials in the meteors could be broken down into simpler products that include the OH hydroxyl radical.
To search for these effects, airglow data were collected by a Bomem Michelson M-150 interferometer. This interferometer operates at 4 cm-1 resolution (apodized) with a scan rate of about 1 scan every 3 seconds. The interferometer field of view is 1.5° and it is sensitive from 1 to 1.65 micrometers. An intensified Xibion camera recorded the instrument field of view during the flight, providing information on the pointing elevation and azimuth. This sensor operated almost continuously during the entire 1999 Leonid MAC campaign and collected an extensive set of night airglow spectra.
