Ground‐based measurements of OClO and HCl in austral spring 1993 at Arrival Heights, Antarctica

Ground‐based measurements of stratospheric OClO and HCl total columns are reported. The data were obtained during the spring season of 1993 at Arrival Heights (77.8°S/166.7°E), Antarctica, using zenith sky and direct sun absorption spectroscopy in the visible and infrared spectral regions. Together these data sets represent complementary measurements of chlorine species in Antarctica over an extended period in spring. To illustrate aspects of Antarctic stratospheric chemistry and dynamics that are significant in current studies of ozone depletion, the OClO and HCl data are supplemented by simultaneously measured NO 2 data as well as ancillary data from other sources. Observations of OClO, HCl and NO 2 provide an indication of the degree of the perturbed chemistry that is operating in the spring stratosphere. The measurements illustrate the repartitioning of active chlorine into the less reactive HCl reservoir as spring progresses. Comparison of the data with total ozone and stratospheric temperature records shows that the springtime chlorine variations are in agreement with currently accepted models of Antarctic ozone depletion chemistry.