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Abstract

We present results from an intercomparison program
of CO2, (O2/N2) and 13CO2 measurements from atmospheric
flask samples. Flask samples are collected on a biweekly
basis at the High Altitude Research Station Jungfraujoch
in Switzerland for three European laboratories: the University
of Bern, Switzerland, the University of Groningen,
the Netherlands and the Max Planck Institute for Biogeochemistry
in Jena, Germany. Almost 4 years of measurements
of CO2, (O2/N2) and 13CO2 are compared in this
paper to assess the measurement compatibility of the three
laboratories. While the average difference for the CO2 measurements
between the laboratories in Bern and Jena meets
the required compatibility goal as defined by the World Meteorological
Organization, the standard deviation of the average
differences between all laboratories is not within the
required goal. However, the obtained annual trend and seasonalities
are the same within their estimated uncertainties.
For (O2/N2) significant differences are observed between
the three laboratories. The comparison for 13CO2 yields the
least compatible results and the required goals are not met
between the three laboratories. Our study shows the importance
of regular intercomparison exercises to identify potential biases between laboratories and the need to improve the quality of atmospheric measurements.