Human activities are changing the Earth and its atmosphere. Long-term records show a rise in the global average temperature over the past few decades. Other observations reveal changes in the composition of the Earths atmosphere such as thinning of the stratospheric ozone layer and increases in the concentration of greenhouse gases. Scientists do not fully understand how these changes will affect climate. Therefore, highly accurate, long-term measurements are essential for gaining a better understanding of the processes that control climate change.
The Stratopsheric Aerosol and Gas Experiment (SAGE III) is a fourth-generation satellite instrument designed to observe the long-term health of the upper atmosphere. Managed by NASA Langley Research Center, SAGE III is part of NASAs Earth Science Enterprise program of climate research. It launched aboard a Russian Meteor 3M spacecraft in December 2001 for a three year mission, a collaboration between NASA and the Russian Aviation and Space Agency (RASA). It extends a long-term working relationship between the United States and Russia to understand Earths environment.
The goal of SAGE III is to measure high-resolution vertical profiles of key components of the upper atmospherethe most important being ozone, aerosols, (suspended particles) and water vapor. These measurements will enhance our understanding of climate and how human activities influence it. This information will enable national and international leaders to make informed policy decisions on climate change.