Infrared Water Vapor Continuum Absorption: New Atmospheric Electrical Measurements and Theory
Abstract
The infrared (IR) continuum absorption, and probably similar absorption at longer wavelengths, can be attributed to populations of electrically-neutral water clusters that are present in near-Gaussian size distributions in water vapor and moist air. These neutral water clusters exist in equilibrium with much smaller populations of their water ions. Therefore, behavior of the ions and their equilibrium, IR-absorbing neutral clusters can be studied by careful measurements of the electrical conductivity of atmospheric moist air. Some results from a year of such measurements are presented and discussed. The most significant conclusions are: 1) the vapor continuum absorption almost certainly is due to water clusters; 2) prime sources of such clusters include fine water droplets, and finely-structured water films on surfaces, at higher relative humidities (RH) in electric fields typical of those in the earth's atmosphere; 3) the variability of the continuum absorption arises from many factors, some of the most important of which are vapor RH, state of equilibrium, and fineness of droplets and surface water film structure; and 4) the continuum absorption at any wavelength is due only to these clusters of the distribution that absorb there, therefore, the total vapor cluster population cannot be estimated by measurements at a single wavelength.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1989
- Accession Number
- ADA212594
Entities
People
- Hugh R. Carlon
Organizations
- Edgewood Chemical Biological Center