MEASUREMENT OF STRATOSPHERIC DISTRIBUTIONS OF (H2O)-O-16, (H2O)-O-18, (H2O)-O-17 AND (HDO)-O-16 FROM FAR INFRARED-SPECTRA

The stratospheric concentration profiles of H2O-16 and of the isotopic species H2O-18, H2O-17, and HD-O-16, are retrieved from far-infrared emission spectra recorded by a balloon-borne Fourier transform spectrometer with 0.0035 cm-1 resolution. The retrievals were carried out using the global-fit procedure on a statistically significant number of transitions for each isotope in the 40-85 cm-1 spectral region. The concentration and the relative mixing ratio distributions of each isotope are given along with the resulting isotopic ratios. A comparison of these results with the natural isotopic abundances shows that there is a depletion of up to 56 +/- 8% of the D-containing isotope of water, while no significant deviation is obtained for the other isotopes within the error bars. A comparison of our results with previously reported measurements is also given.