THE DETECTION OF ATMOSPHERIC DUST AND TEMPERATURE INVERSIONS BY TWILIGHT SCATTERING

Abstract

Equipment designed to detect variations in the rate of change of illumination from a small part of the sky during twilight was used in the hope of locating layers or regions of dust particles in the atmosphere. The measurements prominently displayed dust accumulations below about 20 kilometers, which were found to correspond very closely to the temperature inversions determined by nearby radiosonde flights. Dust near the tropopause was conspicuously revealed by the results, and its wide variations in amount were closely correlated with the passage of weather systems. The temperature inversion near 80 km was also readily detectable, and changes in the scattering from it suggested that dust was also present there. Systematic variations from day to day appeared to be related to the advent of visually observed meteor showers and to a “world rainfall” figure. Abstract Equipment designed to detect variations in the rate of change of illumination from a small part of the sky during twilight was used in the hope of locating layers or regions of dust particles in the atmosphere. The measurements prominently displayed dust accumulations below about 20 kilometers, which were found to correspond very closely to the temperature inversions determined by nearby radiosonde flights. Dust near the tropopause was conspicuously revealed by the results, and its wide variations in amount were closely correlated with the passage of weather systems. The temperature inversion near 80 km was also readily detectable, and changes in the scattering from it suggested that dust was also present there. Systematic variations from day to day appeared to be related to the advent of visually observed meteor showers and to a “world rainfall” figure.