In the stratosphere, ozone shields life at the surface from harmful solar ultraviolet radiation and plays an important role in controlling the circulation of air in the upper atmosphere. Changes in ozone distribution, like the ozone hole that forms in the spring over Antarctica, are also a concern to health officials because of the possibility for increased cases of melanoma and other skin cancers, cataracts and immune deficiencies in humans. Scientists now realize that ozone is being destroyed over the Arctic during late winter and more slowly over middle latitudes. A primary objective of the SAGE III instrument is to make accurate, long-term measurements of the concentraton of stratospheric ozone and other chemical species that control the distribution of ozone.
 

SAGE III
Introduction
Aerosols and volcanic eruptions
Ozone in the upper atmosphere
Water vapor observations
Making measurements at the edge of the Earth

SAGE measurements of stratospheric ozone extend from 1979-1981 and 1984-present. This long-term, stable data set has proven invaluable in determining the decadal trend in ozone particularly in the lower stratosphere. SAGE ozone measurements are a key element in on-going assessments of ozone trends by SPARC (Stratospheric Processes and their Role in Climate) and UNEP (the United Nations Environmental Programme). SAGE III will extend this data set through much of the next decade. (Image courtesy NASA Langley Research Center)

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