Experimental investigation of the self- and N_2-broadened continuum within the ν_2 band of water vapor

Abstract

We present an experimental study of the self- and N(2)-broadened H(2) O continuum in microwindows within the ν(2) fundamental centered at ~1600 cm(-1). The continuum is derived from transmission spectra recorded at room temperature with a BOMEM Fourier transform spectrometer at a resolution of ~0.040 cm(-1). Although we find general agreement with previous studies, our results suggest that there is significant near-wing super-Lorentzian behavior that produces a highly wave-number-dependent structure in the continuum as it is currently defined.

Infrared spectrum of the continuum and dimer absorption in the vicinity of the O2 vibrational fundamental in O2/CO2 mixtures

“…The Blackman-Harris apodization was used. Spectra were recorded using a 2 m base length multi-pass White cell designed by Olson [17]. The optical path length used in these experiments was 84.05 m. The temperature range of this cell has been expanded to cover from 193 to 360 K. Other improvements include changes in the optical bench support design to minimize baseline drift under with changes in sample pressure.…”

Impact of an improved longwave radiation model, RRTM, on the energy budget and thermodynamic properties of the NCAR community climate model, CCM3

“…CIM demonstrated the importance of the foreignbroadened water continuum absorption (due to water-N2 and water-O2 collisions) in the 200-600 cm -• spectral region (which is absent from RSB), especially in the upper troposphere. The validity of the CKD foreign continuum has also been established in the 1600 cm -• spectral region [Tobin et al, 1996]. The CKD continuum model is an integral component of both LBLRTM and RRTM and continues to be validated against surface spectral radiance measurements.…”

The Water Vapour Continuum: Brief History and Recent Developments

“…3 Secondly, a whole series of reports of further laboratory measurements by Burch and colleagues (e.g., Burch 1981Burch , 1985Burch and Gryvnak 1980;Burch and Alt 1984) presented what were then the most detailed measurements of the continuum, in terms of ranges of wavelengths and temperatures, many of which provided the backbone to the Clough et al (1989) work. Other laboratory and field measurements across a wide range of conditions in this period contributed to further assessment and improvement of continuum models (e.g., Han et al 1997;Tobin et al 1996Tobin et al , 1999Varanasi and Chudamani 1987). Grant (1990) presented a review of a wide range of measurements in the mid-infrared window.…”