SOME OBSERVED SHORT TERM AND DIURNAL VARIATIONS OF STRATOSPHERIC DENSITY ABOVE 30 KM

Some observed variations of atmospheric density between 30 and 65 km over a short time period, including night-day variations, are presented. Five density profiles, three in darkness and two in daylight, were obtained with meteorological sounding rockets over a 48-hour period. The temperature was measured directly with a 0.32 mm bead thermistor, and the atmospheric density was derived using the hypsometric formula. Recent correction techniques have reduced density errors to 2 per cent up to 55 km, approximately 2.5% from 55 to 60 km, and within 3% from 60 to 65 km. Over the altitude range examined, the most significant variations in density occur in the region of 45 to 60 km, which is not surprising since these 5 observations as well as many others show this portion of the stratosphere to be the most active in terms of large temperature changes. Density variations of up to 8% were observed at equivalent altitudes over as short a period as 1 hour and 45 minutes from darkness into daylight. In a 24-hour period, variations of as much as 16.5% were observed. (Author)