Further Spectral Observations of Grenade Glow Clouds in the Lower Thermosphere

Abstract

SummaryThe spectral energy distribution is given for the glow clouds resulting from the explosion of aluminized grenades in the range of altitude from 100 to 200 km. At night, over much of the spectral range from 300 to 800 nm, the spectrum is a continuum very similar to that of a black body at 4000-5000 o K. At twilight, emissions resulting from resonant scattering of sunlight by AI, K, Ba, Na, and AIO are superimposed on, and dominate, the continuum.

The Radiant Output of Grenade Glow Clouds in the Lower Thermosphere

“…From these results it can be shown that the maximum radiant power could be produced by reaction (2) were it chemiluminescent. However, this would give Al line emissions at night and, since they are not observed, we prefer to use the chemiluminescent reaction (Rosenberg 1963) k4 AIO+O ---+ AI02+hv, (3) and this is consistent with the observations of Johnson and Low (1967), who showed that the night-time continuum is detectable in twilight clouds as a weak feature underlying the strong AIO band emissions.…”

“…For clarity the curves have not been plotted at the correct relative positions on the ordinate scale and only the slopes of the curves are significant. Johnson and Low (1967) have given some curves showing the relative strengths of the various emissions. I Al 396 nm…”

“…Various authors (Woodbridge 1961;Armstrong 1963;Johnson and Low 1967) have discussed observations made of the glowing clouds that result when grenades containing aluminium are exploded at night or at twilight in the region of the upper atmosphere between 100 and 200 km altitude. Armstrong (1963) and Johnson and Low (1967) have shown that the night-time spectra are continua and that the twilight spectra are dominated by aluminium monoxide (AlO) bands due to resonant scattering of sunlight.…”

“…Armstrong (1963) and Johnson and Low (1967) have shown that the night-time spectra are continua and that the twilight spectra are dominated by aluminium monoxide (AlO) bands due to resonant scattering of sunlight. The night-time continuum also appears as a weak feature underlying the AlO bands.…”

“…We have made observations of these clouds using a special spectroradiometer, described by Johnson (1965) and Johnson and Low (1967), a scanning photometer, described by Johnson and Lloyd (1963), and a total radiation photometer with a 2° field of view. All instruments use logarithmic amplifiers (Groves 1965), with response times of a few milliseconds.…”