Heavy ozone enrichments from ATMOS infrared solar spectra

Vertical enrichment profiles of stratospheric (OOO)-O-16-O-16-O-18 and (OOO)-O-16-O-18-O-16 (hereafter referred to as O-668(3) and O-686(3) respectively) have been derived from space-based solar occultation spectra recorded at 0.01 cm(-1) resolution by the ATMOS (Atmospheric Trace MOlecule Spectroscopy) Fourier-transform infrared (FTIR) spectrometer. The observations, made during the Spacelab 3 and ATLAS-1, -2, and -3 shuttle missions, cover polar, mid-latitude and tropical regions between 26 to 2.6 mb inclusive (approximate to 25 to 41 km). Average enrichments, weighted by molecular O-48(3) density, of (15 +/- 6)% were found for O-668(3) and (10 +/- 7)% for O-686(3). Defining the mixing ratio of O-50(3) as the sum of those for O-668(3) and O-686(3), an enrichment of (13 +/- 5)% was found for O-50(3) (1 sigma standard deviation). No latitudinal or vertical gradients were found outside this standard deviation. From a series of ground-based measurements by the ATMOS instrument at Table Mountain, California (34.4 degrees N), an average total column O-668(3) enrichment of (17 +/- 4)% (1 sigma standard deviation) was determined, with no significant seasonal variation discernable. Possible biases in the spectral intensities that affect the determination of absolute enrichments are discussed.