Accession Number:

ADA214202

Title:

Anomalous Absorption by Atmospheric Water Vapor and Stabilized Water Fogs in the Infrared and CM-Wave Regions

Descriptive Note:

Technical rept. Jan 1978-Dec 1982

Corporate Author:

CHEMICAL RESEARCH DEVELOPMENT AND ENGINEERING CENTER ABERDEEN PROVING GROUND MD

Personal Author(s):

Report Date:

1989-10-01

Pagination or Media Count:

26.0

Abstract:

Measurements of anomalous or excessive absorption by atmospheric water vapor, i.e., absorption in excess of water monomer absorption and droplet scattering predictions, are analyzed for the infrared and 5-17cm regions. Both fair weather and fog data are considered. It is found that observations in both spectral regions can be explained by clustering hydrogen bonding of approx. . 001 of vapor molecules. The development leads to several tentative conclusions 1 equilibrium cluster populations and maximum absorption are only attained for vapor in contact with liquid water 2 the clusters are formed by evaporation, are large, and cannot be modeled by Boltzmann statistics 3 cluster modes can account for unexplained spectral features at 5-17cm 4 excessive absorption both in the infrared and 5-17cm regions probably can be explained by the same cluster species. In the appendix, the visible and infrared optical properties of evaporation stabilized water fogs also are considered. Evaporation of artificial water fogs can be retarded by the application of coatings of long-chain fatty alcohols to the droplets during generation. Measurements are described, and droplet diameters and mass extinction coefficients are reported for water fogs coated with cetyl alcohol 1-hexadecanol from a commercial generator. aw

Subject Categories:

  • Atmospheric Physics
  • Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE