M. Jaramillo

High concentrations of chlorine monoxide at low altitudes in the Antarctic spring stratosphere: diurnal variation

The Stony Brook ground-based remote sensing mm-wave spectrometer was used to measure chlorine monoxide in the stratosphere over McMurdo Station, Antarctica during the austral spring of 1986. From the data collected, we find strong evidence for abnormally high concentrations of CIO at low altitudes—as much as two orders of magnitude greater than standard theories predict at 20-km altitude at mid-latitudes. This low-altitude CIO changes cyclically on a diurnal basis, and also secularly during the September–October observing period. A study of the diurnal variation of the low-altitude ClO is presented here. We conclude that chlorine is crucially involved in the springtime destruction of Antarctic ozone.

Feasibility of observations of stratospheric trace gases using the Hubble Space Telescope

The stellar occultation method has been successfully used in the past from orbiting observatories to measure concentrations of certain trace gases in the Earths mesosphere. The greatly improved spectroscopic capabilities of the Hubble Space Telescope (HST) have prompted recent suggestions for its use to measure stratospheric C10. We examine this possibility along with that for other species relevant to the chemistry of the ozone layer. We conclude that stratospheric (as opposed to mesospheric) observations with HST are not practical, in part because of its orbital and pointing characteristics, but primarily because the high opacity of stratospheric ozone over most of the band-pass of the HSTs most suitable spectrometer will obscure observation of other trace species, such as C10, having mixing ratios <10−3 that of ozone.