This project is to support the study of the causes of the antarctic springtime ozone depletion. A series of ozonesonde balloons will be flown from Palmer Station from August through October 1987. The information obtained will be of value to both the second National Ozone Expedition (NOZE-II) in McMurdo and the NASA aircraft measurements which will be operated out of Chile. The proposer is an expert in the measurement of ozone by this technique.