Colloquium: Eliza Harris

Isotopic measurements of greenhouse gases at background stations help constrain large-scale atmospheric processes and global biogeochemical cycles. Mountain sites like Jungfraujoch capture signals from broad regions, making them useful for tracking long-term trends in CO₂, CH₄, and N₂O. Isotopes add key information about the sources, sinks, and processes affecting these gases. Measurements are typically made using isotope ratio mass spectrometry or laser spectroscopy, though both have limitations. Despite challenges such as weak signals and calibration issues, these observations remain valuable, with ongoing improvements needed in time series, calibration, and interpretation.