CO2, CH4, N2O, SF6 and CO greenhouse gas measurements at Jungfraujoch
The CO2, CH4, N2O and CO measurements complement the halogenated greenhouse gases measured as part of the HALCLIM / InGOS / AGAGE activities. The joint observations allow monitoring a comprehensive set of the most important greenhouse gases and make Jungfraujoch the best equipped high-altitude research station in this respect.
Continuous observations of carbon monoxide at Jungfraujoch are available since 1996 using commercially available Non-Dispersive Infrared Absorption technology (NDIR). In addition, in-situ measurements of CH4, N2O, and SF6 started in early 2005 with a custom-built gas chromatograph equipped with a flame ionization detector and an electron capture detector (GC-FID/ECD) allowing quasi-continuous analysis every 24 to 30 minutes.
In December 2014, the measurements were complemented by high-resolution, continuous N2O measurements. To do so, Empa is operating an off-axis integrated cavity output spectrometer (OA-ICOS) next to the GC-FID/ECD system. The superior precision and the continuous operation of the OA-ICOS compared to GC-ECD allow measuring short-term N2O variations that could not be detected with gas chromatography before. The laser spectrometer is also capable of measuring CO and H2O with high precision. The availability of the H2O signal allows measuring without sample drying and calculating dry air mole fractions by applying a humidity correction to the fully unaltered humid gas stream accounting for dilution and spectroscopic effects.