The water-vapor continuum and selective absorption in the 3 to 5 micrometer spectral region at temperatures from 311 K to 363 K.

Published

May 15, 2011

Author(s)

Yuri I. Baranov, Walter J. Lafferty

Abstract

Experimental data on the water vapor continuum, which are based on pure H2O spectra recorded recently at NIST with a resolution of 0.1 cm-1, are presented. The sample temperatures and pressures varied from 311 K to 364 K and from 2.8 kPa (21 torr) to 15.1 kPa (113 torr), respectively. The path length extended from 68 m to 116 m. At these conditions the continuum absorption in the 4 μm atmospheric window is quite detectable reaching as high as 4%. The spectra processing is based on calculation, fitting and removal of the ro-vibrational structure. The absorption coefficients measured around 5 μm are in good agreement with those of the widely used MT_CKD continuum model. However, at shorter wave lengths, the values diverge dramatically the difference increasing up to one order of magnitude. Despite the comparatively large uncertainty of our data, analysis and comparison with all other available results leads us to the conclusion that MT_CKD self broadened continuum is rather greatly underestimated over the 4 μm atmospheric window. About 140 individual line strengths were retrieved after spectral processing. The deviation of the measured intensities from those of the HITRAN data base is randomly scattered around zero within several percent. No systematic term has been detected.

Citation

Journal of Chemical Physics

Volume

112

Issue

8

Pub Type

Journals

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DOI Link

Keywords

Continuum, Infrared Spectral Region, Water-Vapor

Citation

Baranov, Y. and Lafferty, W. (2011), The water-vapor continuum and selective absorption in the 3 to 5 micrometer spectral region at temperatures from 311 K to 363 K., Journal of Chemical Physics, [online], https://doi.org/10.1016/j.jqsrt.2011.01.024 (Accessed December 14, 2024)