Field and laboratory experiments on the 8 to 14 ?m spectral window of the terrestrial atmosphere

Abstract

This paper summarizes experiments on the spectral properties of the terrestrial atmosphere in the infrared 8 to 14 μm spectral window performed with laser photoacoustic spectroscopy on the basis of results from previous airborne measurements on spectral emission. Following a description of the experimental arrangement, novel results on supersaturated water vapor, continuum and line absorption are presented and discussed in relation to actual models of the atmosphere. Besides the measurement of the absorption by supersaturated water vapor in a diffusion chamber, the experimental determination of the water-pressure dependence of the continuum absorption at −10°C and the identification of four weak and narrow absorption lines in the 8 to 14 μm window as pure high-J rotational transitions of the H2O molecule are of interest.