Vienna Urban Carbon Laboratory - Isotopes

The VUCL will test the latest measurement-based emissions monitoring methods to address a pressing scientific research question with practical and political implications – Can Vienna’s greenhouse gas (GHG)emissions be adequately measured? The need for climate action in cities is critical. Systems that quantify local GHG emissions to evaluate mitigation measures are thus growing in importance and will undergo increasing levels of scrutiny. Measurement-based systems offer enormous potential; however, there is still substantial research required before they can be established within routine monitoring systems which currently rely on emission inventories. The VUCL thus proposes a number of cutting-edge scientific investigations, involving tall-tower eddy covariance measurements of net carbon dioxide (CO2) and methane (CH4) fluxes and CO2 isoflux measurements, as well as test campaigns with a differential column sensor network to measure upwind-downwind gradients in CO2 and CH4 concentrations. The VUCL brings together the Environment Agency Austria (EAA), the University of Natural Resources and Life Sciences Vienna (BOKU), the Technical University Munich (TUM) and A1 Telekom Austria AG (A1) and aims to: advance the science in the field of measurement-based GHG emissions estimates; showcase the latest measurement-based methods to city administrators; and lay the foundations for an adequate local monitoring system for quantifying total and sector specific emissions reductions. Investigating the isotope signatures of the different fuels combusted in Vienna, we expect a clear separation between petrol and diesel on the one hand (delta13C -30 ‰) and natural gas on the other (delta13C -40 bis -60 ‰). We thus hypothesize that the measurement campaigns with a cavity ring-down laser absorption spectrometer will produce a seasonal trend in the isotopic signatures, with lighter CO2 concentrations and isofluxes in the winter due to increased natural gas combustion for space heating.