Water vapor absorption measurements and comparisons with predictions are discussed along with ongoing and planned research efforts. Hydrogen fluoride (2.7-3.0 μm) laser line measurements as functions of temperature and pressure are presented. Comparisons of these results with predictions suggest the need for using an improved set of absorption line strengths, and a super Lorentz/Voigt line shape. Results thus far have been carried to -18°C although ongoing efforts plan to extend these to -50°C. Deuterium fluoride (3.5-4.0 μm) laser line measurements have been made under mid-latitude summer conditions and as a function of temperature and pressure. The measured absorption in this region is about twice as large as current predictions and ex-hibits a larger self-broadening term. These results can be modeled by assuming both a far wing and a water-aggregate contribution. Other ongoing efforts include determination of pressure and temperature dependencies of water vapor absorption in the 8-12μm region using a carbon dioxide laser including considerations of possible dimer contributions as well as similar measurements in the 0.3-2mm region using a far infrared/submillimeter laser. Possible physical models for the water vapor absorption (continuum or anomalous absorption) in the 3-5 μm and 8-12μm regions are also discussed.

Date Published: 19 December 1979
PDF: 8 pages
Proc. SPIE 0195, Atmospheric Effects on Radiative Transfer, (19 December 1979); doi: 10.1117/12.957924

Published in SPIE Proceedings Vol. 0195:
Atmospheric Effects on Radiative Transfer
Claus B. Ludwig, Editor(s)