Computed Transmission Spectra for 27-Micron H_2O Band

The spectral line positions, strengths, and half-widths of the ν1, 2ν2, and ν3 bands of the 2.7 μ region of absorption for water vapor have been computed and checked against laboratory spectra for the range 2857 to 4444 cm−1. From a knowledge of these lines theoretical transmission spectra at infinite spectral resolution at a given pressure, temperature, and water vapor concentration have been determined. From the theoretical transmission spectra certain degraded spectra for finite slit-width are computed, and a comparison is made with a high-altitude atmospheric absorption spectrum of solar radiation.