Jungfraujoch measurement site

The increase of carbon dioxide concentration in the Earth's atmosphere is the dominating driver for global warming and climate change. Its ecological and economical impacts are widely recognized, and the quantification of the sources and sinks of CO₂ is thus of great scientific, political and economical interest. CO₂ concentration measurements alone are not sufficient to gain information about the exchange fluxes between the different carbon pools (ocean, biosphere and atmosphere). However, individual fluxes are marked with specific isotopic CO₂ signatures, which make the study of the stable CO₂ isotope ratios (d¹³C-CO₂ and (d¹⁸O-CO₂) highly attractive.

With respect to the global CO₂ cycle models it would be highly valuable to gain information about seasonal and regional signatures of CO₂ sources. Such large-scale, integrated information can be obtained by combining the continuous and high-precision measurements performed at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.) with state of the art backward Lagrangian particle dispersion simulations.

One key aspect of this project is the long-term monitoring of d¹³C-CO₂ and d¹⁸O-CO₂ at a time scale of minutes, using a quantum cascade laser based absorption spectrometer. This instrument has successfully been employed in several field campaigns, reaching a precision better than 0.02 ‰ in nearly unattended operation, showing the feasibility of continuous, high-precision measurements which would be highly welcome for a wide range of activities, such as the Integrated Carbon Observation System (ICOS).