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Determination of atmospheric water‐vapor densities from measurements of the 6943.8‐Å absorption line strength
Author(s) -
Johnson M. M.,
LaGrone A. H.
Publication year - 1973
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs008i005p00407
Subject(s) - water vapor , line (geometry) , materials science , attenuation coefficient , vapour pressure of water , bar (unit) , atmospheric pressure , absorption (acoustics) , analytical chemistry (journal) , laser , density of air , optics , chemistry , meteorology , physics , geometry , mathematics , chromatography , composite material
The effects of pressure and temperature variations on the determination of water‐vapor densities from ruby‐laser radar returns are considered. At the center of the 6943.8‐Å water‐vapor line, the thermal dependence of the absorption cross section is almost negligible while the pressure dependence is not. Water‐vapor densities should be deduced from the line strength, which is independent of pressure, rather than the absorption coefficient as has been done previously. The 6943.8‐Å line strength and line width were measured over a fixed‐length atmospheric path using a ruby laser as 0.17 cm −1 g −1 cm 2 and 0.098 cm −1 bar −1 (295 K), respectively, with standard error estimates of 16 and 9%.