This award will continue the measurement of trace atmospheric gases that are considered to be important to the formation of the annual antarctic ozone hole and also are important for controlling the Earth's radiation balance. Two techniques will be used. At McMurdo, in conjunction with the New Zealand Antarctic Research Program, infrared absorption measurements using the sun as an infrared radiation source will continued during the time of the ozone hole, as they have for the past few years. A new instrument has been installed at South Pole that will measure emitted atmospheric infrared radiation in the winter (polar night) as well as absorbed solar radiation in the summer. This instrument will be operated every day. In both cases the wave number region to be covered will be 750-4000 inverse centimeters. The gases that should be detected include hydrochloric acid, nitric acid, nitrogen dioxide, chlorine nitrate, nitrous oxide, methane, ozone and the chlorofluorocarbons 11 and 12 (F11 and F12) during the time of the ozone hole and the total column abundances over South Pole of nitric acid, ozone, water vapor, F11 and F12 on a continuous basis for the entire year. The measurements are not only important for achieving a better understanding of the stratospheric chemistry that causes the ozone depletion but also for determining how radiatively important trace species (RITS) are affecting the Earth's climate. This research is jointly supported by the Atmospheric Chemistry and Polar Aeronomy and Astrophysics programs at NSF and also by the Upper Atmospheric Research Program at NASA.
