Near-ultraviolet absorption spectroscopy in the wavelength range from 330 to 370 nm was used to measure O3, NO2, OClO, and BrO at McMurdo Station (78¿S) during 1987. Visible absorption measurements of O3, NO2, and OClO were also obtained using the wavelength range from about 403 to 453 nm. These data are described and compared to observations obtained in 1986. It is shown that comparisons of observations in the two wavelength ranges provide a sensitive measure of the altitude where the bulk of atmospheric absorption takes place. The measurements indicate that the bulk of the NO2 column abundance is located near 30 km, while those of OClO and O3 are near 20 km. The measurements of NO2 display a systematic increase during the month of September, probably reflecting the release of odd nitrogen from reservoirs formed earlier in the winter season. The measurements of OClO display a strong diurnal variation, with considerably higher values being obtained in the evening than those measured in the morning. The evening twilight OClO column abundances obtained in 1987 were notably larger than those in 1986, perhaps because stratospheric temperatures were colder, and associated heterogeneous chemistry may have been more intense. This in turn implies a faster rate of ozone destruction in 1987 than in 1986 by halogen chemistry. These observations provide important constraints on the coupled nitrogen-halogen chemistry of Antarctic spring and its influence on the springtime Antarctic ozone depletion. ¿ American Geophysical Union 1989