Research Objectives:
Using passive infrared instruments, this project measures year-round atmospheric chemistry to acquire better data for the photochemical transport models used to predict ozone depletion and climate change. The ozone hole has shown how sensitive the southern polar stratosphere is to chlorine, and although gradual healing of the hole is expected, model predictions indicate a possible delay in recovery because of the impact of global warming on the catalytic ozone destruction process.
Since most satellite instruments do not sample the polar regions in the winter, ground-based instruments can make important contributions. The data from these instruments also provide validation for new satellite sensors. In the first year of the project, team members installed two spectrometers, one at Amundsen-Scott South Pole Station and another at McMurdo Station for year-round operation, and a solar spectrometer at South Pole Station for summer operation. Project researchers collaborate with and receive data from the New Zealand National Institute for Water and Air Research, which operates a similar solar spectrometer at Arrival Heights. During the polar night, two instruments will provide important information on nitric acid and denitrification, as well as dehydration, and high-resolution spectra from which are derived vertical profiles, vertical column amounts of many molecules important in the ozone destruction process, and atmospheric tracers. Specifically, project team members will derive year-round column abundance measurements of nitric acid, methane, ozone, water, nitrous oxide, the chlorofluorocarbons (CFCs), and nitrogen dioxide.
The solar instruments will provide some altitude profile information about those molecules and others. The data will be used to:
+ Determine the current state of nitrogen oxide partitioning,
+ Measure denitrification, vapor profiles in the stratosphere, and dehydration,
+ Determine current CFC and stratospheric chlorine levels, and
+ Gain more insight into vortex-related chemical and dynamic effects.
The data will also allow photochemical transport modelers to compare outputs with actual measurements, especially at intermediate stages. As the recovery from ozone destruction begins, it is important to have a data set that comprehensively covers the major constituents of both the catalytic ozone destruction sequence and global warming, in order to place the relative influence of the two mechanisms in perspective.
