Distribution of Water Vapor in the Stratosphere as Determined from Balloon Measurements of Atmospheric Emission Spectra in the 24–29-μm Region

Abstract

The stratospheric water vapor mixing ratio altitude profile has been derived from spectral observations of the downward night emission from the pure rotation water vapor lines in the 24–29-μm region of the spectrum. The data were obtained during two balloon flights, made on 22 February 1971 and on 29 June 1971, using a balloon-borne spectral radiometer with ~2 cm⁻¹ resolution. The observed radiances have been fitted to line-by-line, layer-by-layer radiance calculations, from which the water vapor mixing ratio between 10 km and 30 km has been derived. The resulting mixing ratio altitude profiles from both flights show a broad minimum around 15 km and a broad maximum around 25 km with a range of values of 6 × 10⁻⁷g/g to 4 × 10⁻⁶ g/g.