Characterization of local and regional CO2 sources based on continuous measurement of the stable isotopes

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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 0.05 ‰ 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).