Mobile Oxygen Measuring System

• Subject Area: Agriculture, Forestry and Veterinary Medicine
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437452730

Measurements of atmospheric oxygen (O2) in the troposphere have proven to be one of the most powerful tools to study the carbon cycle at global scale, quantifying the carbon dioxide (CO2) sink of terrestrial ecosystems and oceans. Atmospheric O2 is closely related to the carbon cycle through photosynthesis and respiration, and is influenced by sources of nitrogen during plant uptake. O2 thus carries valuable information about ecosystem processes that cannot be learned from CO2 alone and thus offers an opportunity to develop a new tracer for carbon and nitrogen cycle processes at ecosystem level. However, such measurements of O2 fluxes at ecosystem level are largely lacking. With the proposed instrument Mobile O2 measuring system we want to perform measurements of the O2 exchange between land ecosystems and the atmosphere using the eddy covariance technique. This has two major challenges. First, it is technically challenging to measure atmospheric O2 at ppm level against a background concentration of 210 000 ppm (21%). Second, the eddy covariance approach requires fast measurements at the scale of 2-10 Hz in order to resolve all relevant turbulent eddies responsible for the vertical transport.The proposed instrument is a combination of commercial standard products and prototypes that will need to be assemble ourselves. It will be able to measure O2, CO2 and H2O fluxes between the land surface and the atmosphere at hourly time scale. It will also record meteorological variables that influence the measured fluxes. The instrument will be field deployable and will be used at various flux tower sites of the Bioclimatology group (University of Goettingen) and contribute to various projects. The proposed measurements are worldwide unique and offer an enormous potential to investigate the carbon cycle at ecosystem scale and to contribute to processes understanding of relevance at global scale.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Mobile Sauerstoff-Feldmessstation
• Instrumentation Group: 1520 Meßgeräte für Gase (O2, CO2)
• Applicant Institution: Georg-August-Universität Göttingen
• Leader: Professor Dr. Alexander Knohl