Apparent Temperatures of Some Terrestrial Materials and the Sun at 4.3-Millimeter Wavelengths

Abstract

This paper describes a 4.3-mm radiometer and measurements made with it of the apparent temperature of various terrestrial materials, the attenuation through the atmosphere and the temperature of the sun. Materials whose apparent temperatures were measured included water, wood, metal, grass, asphalt, gravel and asbestos. Since their apparent temperatures are dependent upon their reflectivity, these data are interpreted in terms of the background reflected by the materials. The attenuation vertically through a clear sky ranged between 1.6 and 2.3 db. The sun, of optical disk size, was found to be between 104 and 1.2×104°K on May 3 and June 17, 1957.