Beginning in 1978, three successive automated high-frequency in situ experiments – the Atmospheric Lifetime Experiment (ALE), the Global Atmospheric Gases Experiment (GAGE), and the Advanced Global Atmospheric Gases Experiment (AGAGE) – have documented the long-term behavior of the measured concentrations of these gases over the past 20 years, and show both the evolution of latitudinal gradients and the high-frequency variability due to sources and circulation. Research summarizes interpretations of these measurements using inverse methods to determine trace gas lifetimes and emissions.

Visit our Research Highlights page, or browse our publications for a more complete listing of research produced since 1978.