Accession Number : AD0689805

Title :   RADIATION PROPERTIES OF THERMISTOR BEADS,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF METEOROLOGY

Personal Author(s) : Toscano,William Michael

Report Date : 10 FEB 1969

Pagination or Media Count : 80

Abstract : Meteorological measurements of temperatures in the atmosphere are made with thermistor beads which are attached to the tips of rocketsondes. Errors in these measurements are a consequence of heat transfer processes between the bead and its environment; a significant heat transfer process is thermal radiation from the sun to the bead. Thermistor beads are coated with vacuum deposited aluminum in order to minimize the effects of thermal radiation; in order to evaluate these effects, the radiative properties of the beads must be determined. The electromagnetic theory is applied to a specular isotropic aluminum surface to determine the monochromatic hemispherical, normal and directional emittances in the wavelength interval .486 microns to 2.0 microns. Due to the geometrical shape of the bead, an approximate average monochromatic absorptance is defined and calculated in the wavelength interval .546 mirons to 2.0 microns. Five randomly selected thermistor beads are tested for individual monochromatic absorptance in the wavelength range of .55 microns to 2.0 microns. (Author)

Descriptors :   (*ATMOSPHERIC SOUNDING, THERMISTORS), (*THERMISTORS, REFLECTIVITY), RADIOSONDES, INFRARED RADIATION, THERMAL RADIATION, EMISSIVITY, ELECTROMAGNETISM, ABSORPTION, HEAT FLUX, MONOCHROMATIC LIGHT, DETECTORS

Subject Categories : Atmospheric Physics
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE