LIMB VIEW SPECTRUM OF THE EARTH AIRGLOW

Sometimes the Earth's airglow layer, when observed in the limb view, a ppears to be a double layer. During one of these occasions we were abl e to obtain absolute spectral intensity and altitude profiles for most well-known airglow features from the space shuttle on the STS-37 miss ion. The lower of the two airglow layers consisted of the OH Meinel ba nds, the ground state of the 02 atmospheric band at 762 nm and an inte nse nighttime sodium layer at 598 nm peaking near 92 km. The upper air glow layer consists of the atomic oxygen lines at 557.7, 630, and 636. 4 nm, and a blue green continuum. Significant 557.7, 630, and 636.4 nm 01 emissions were observed to extend above 110 km into the lower F re gion. The volume emission rate distribution as a function of altitude was modeled, and the model limb intensity distribution was compared to the data. From the spectral profile of the modeled volume emission di stribution, the green continuum located at 103 km +/- 2 km altitude wa s identified as recombination emission of NO2 produced by a dense NO l ayer. Another layer which was present at each of the modeled wavelengt h regions had a volume emission peak at 90 km. Our observations did no t show the presence of continuum emission with increasing intensity to ward the near infrared. The observed regions were quite near the equat or.