Atmospheric Structure At 130-200 Km Altitude From Observations On Grenade Glow Clouds During 1962-63

Abstract

Glows have been observed at night and at twilight following detonation of aluminized grenades in the altitude range 100-200 km. From observations made with equipment located on the ground, the variation with time of the radiance distribution across the glow clouds has been determined, and this is used to calculate the molecular diffusion coefficient in the region 130-200 km. The derivation of atmospheric density and temperature from the molecular diffusion coefficient is discussed in some detail, and results are presented for a number of Skylark rocket firings at Woomera during 1962 and 1963. The estimated maximum error in density is 30% and in temperature 15%. Within the limit of these errors, no diurnal effects have been detected. Above 150 km altitude, the observations have shown that the initial cloud radii are two to three times greater than predicted. A qualitative explanation of this effect is given by combining blast·wave theory with molecular-flow theory.