Abstract
Abstract. Atmospheric trace gas measurements of greenhouse gases are critical in their precision and accuracy. In the past 5 years, atmospheric measurement and gas metrology communities have turned their attention to possible surface effects due to pressure and temperature variations during a standard cylinder's lifetime. This study concentrates on this issue by introducing newly built small-volume aluminum and steel cylinders which enable the investigation of trace gases and their affinity for adsorption and desorption on various surfaces over a set of temperature and pressure ranges. The presented experiments are designed to test the filling pressure dependencies up to 30 bar and temperature dependencies from −10 ∘C up to 180 ∘C for these prototype cylinders. We present measurements of CO2, CH4, CO and H2O using a cavity ring-down spectroscopy analyzer under these conditions. Moreover, we investigated CO2 amount fractions using a novel quantum cascade laser spectrometer system enabling measurements at pressures as a low as 5 mbar. This extensive dataset revealed that for absolute pressures down to 150 mbar the enhancement in the amount fraction of CO2 relative to its initial value (at 1200 mbar absolute) is limited to 0.12 µmol mol−1 for the prototype aluminum cylinder. Up to 80 ∘C, the aluminum cylinder showed superior results and less response to varying temperature compared to the steel cylinder. For CO2, these changes were insignificant at 80 ∘C for the aluminum cylinder, whereas a 0.11 µmol mol−1 enhancement for the steel cylinder was observed. High-temperature experiments showed that for both cylinders irreversible temperature effects occur especially above 130 ∘C.
Highlights
Atmospheric measurements play a crucial role in understanding the global carbon cycle and its response to anthropogenic perturbation
The coordination of the greenhouse gas measurement network is achieved by the World Meteorological Organization (WMO) through its Global Atmosphere Watch Programme (GAW)
In contrast to the previous studies, the cylinders tested in this study showed enrichments only well below atmospheric pressures for the steel cylinder and the aluminum cylinder before heating
Summary
Atmospheric measurements play a crucial role in understanding the global carbon cycle and its response to anthropogenic perturbation. The number of stations for atmospheric observations has increased continuously. Most of these measurements are conducted in remote areas, and with an increasing number of stations, it is more challenging to ensure the comparability of the measurements. For CO2, these targets correspond to 0.1 μmol mol−1 for the Northern Hemisphere, and 0.05 μmol mol−1 for the Southern Hemisphere (WMO, 2018). These ambitious targets allow the interpretations of fluxes on global and continental scales and to better distinguish the underlying processes (Rödenbeck et al, 2006; Masarie et al, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
