A Search for the e-Effect in the Atmospheric Water Vapor Continuum

Abstract

The e-type effect on the water vapor continuum, suggested by Bignell's laboratory experiments, is investigated in the atmospheric extinction spectrum of the sun between 8 and 13 µm. A classification of atmospheres in terms of precipitable water w, surface air temperature T0, water vapor pressure e0, as well as horizontal visual range V0, proved to be suitable in distinguishing the e-type effect. A procedure for determining the two terms arising from wing and e-effects on the water vapor continuum absorption coefficient, gives results in satisfactory agreement with laboratory experiments. The observed water vapor continuum absorption in the 8?13 µm window is also compared with the extinction due to particles present in the local atmosphere. The data obtained from the measurements allowed us to calculate also the weak absorption coefficients for water vapor in the 0.65?4 µm wavelength interval. They are reported in the Appendix.