Comparison of Experimental and Theoretical Slant Path Absorptions in the Region from 1400 to 2500 cm^-1

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Abstract
The variation of the infrared solar spectrum with altitude was observed during a balloon flight made 28 May 1963. For this flight a biaxial pointing control was used in conjunction with a prism spectrometer, which was set to scan the region from 1400 to 2500 cm-1. The transmittances as observed at various altitudes and wavelengths are presented. The transmittances as observed at selected altitudes are compared with the theoretical transmittances calculated by Plass. The agreement between the calculated and observed transmittance is quite good at the higher altitudes for the 4.3-µ region. The agreement is not good on the long wavelength side of the 4.3-µ band at the lower altitudes. This lack of agreement is due to the contribution of N2O to the observed absorptions. The absorption due to N2O was not considered by Plass.The agreement between the calculated and observed transmittance in the 6.3-µ region is not as good as that in the 4.3-µ region. Part of the lack of agreement is due to the fact that the water-vapor distribution on the day of the flight was different than assumed by Plass.A water-vapor mixing ratio vs altitude profile was determined on the basis of the observed absorptions in the 6.3-µ region; these data are also presented.