Atmospheric transmission in the 1 to 14 μ region (original) (raw)

1951, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences

The transmission of the atmosphere for radiation of wave-lengths between 1 and 14 μ has been determined at sea-level, and its dependence on meteorological conditions investigated. Measurements have been made over paths of 2264 and 4478 yd., and the correlation with visibility and humidity studied in detail at four chosen wave-lengths, 2.18, 3.61, 10.01 and 11.48 μ ,. Spectral transmission curves for typical conditions have been recorded for the complete range 1 to 14 μ and, in addition to the numerous absorption bands due to water vapour arid carbon dioxide, some bands caused by the rarer constituents, in particular N 2 O and HDO, have been observed. Throughout the wave-length range investigated, the transmission varies with the visibility, the effect being less marked at the longer wave-lengths. For example, when, under typical conditions, the visual transmission falls from 75 to 50% per sea mile, the corresponding change at 2.18 μ is from 85 to 73%, and at 10.01 μ from 87 to 83%. ...