5577 A NIGHTGLOW AND ATMOSPHERIC MOVEMENTS

The radiance of the forbidden oxygen emission line at 5577 Å from the night sky depends mainly upon the density of atomic oxygen near 100 km altitude. The profile of atomic oxygen density with altitude varies with, among other things, the strength of any vertical winds at these altitudes. Tohmatsu and Nagata (1963) have examined this problem and conclude that vertical wind speeds of the order of 1 cm sec-1 would have an enormous effect on the radiance of 5577 Å emission. We re-examine the problem, taking an empirical atomic oxygen profile derived from rocket-borne airglow measurements, and consider the effect of adiabatic compression and rarefaction to see if pressure waves in the region are likely to cause significant variations in radiance. We derive, in the course of the analysis, possible atmospheric quenching coefficients for the upper levels involved in the Herzberg and 5577 Å emissions. In addition, our analysis suggests that the eddy diffusion coefficient near 100 km could be less than that favored by Colegrove, Hanson and Johnson (1965). © 1969.