EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Urban greenhouse gas emissions from the Berlin area: A case study using airborne CO2 and CH4 in situ observations in summer 2018

Theresa Klausner1, Mariano Mertens1, Heidi Huntrieser1, Michal Galkowski2,3, Gerrit Kuhlmann4, Robert Baumann1, Alina Fiehn1, Patrick Jöckel1, Magdalena Pühl1, and Anke Roiger1
Theresa Klausner et al.
  • 1Deutsches Zentrum fuer Luft- und Raumfahrt, Institut fuer Physik der Atmosphäre, Wessling, Germany
  • 2Max-Planck-Institut für Biogeochemie, Biogeochemische Systeme, Jena, Germany
  • 3AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Kraków, Poland
  • 4Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland

Urban areas are recognised as a significant source of greenhouse gas emissions (GHG), such as carbon dioxide (CO2) and methane (CH4). The total amount of urban GHG emissions, especially for CH4, however, is not well quantified. Here we report on airborne in situ measurements using a Picarro G1301-m analyser aboard the DLR Cessna Grand Caravan to study GHG emissions downwind of the German capital city Berlin. In total, five aircraft-based mass balance experiments were conducted in July 2018 within the Urban Climate Under Change [UC]2 project. The detection and isolation of the Berlin plume was often challenging because of comparatively small GHG signals above variable atmospheric background concentrations. However, on July 20th enhancements of up to 4 ppm CO2 and 21 ppb CH4 were observed over a horizontal extent of roughly 45 to 65 km downwind of Berlin. These enhanced mixing ratios are clearly distinguishable from the background and can partly be assigned to city emissions. The estimated CO2 emission flux of 1.39 ± 0.75 t s-1 is in agreement with current inventories, while the CH4 emission flux of 5.20 ± 1.61 kg s-1 is almost two times larger than the highest reported value in the inventories. We localized the source area with HYSPLIT trajectory calculations and the high resolution numerical model MECO(n) (down to ~1 km), and investigated the contribution from sewage-treatment plants and waste deposition to CH4, which are treated differently by the emission inventories. Our work highlights the importance of a) strong CH4 sources in the surroundings of Berlin and b) a detailed knowledge of GHG inflow mixing ratios to suitably estimate emission rates.

How to cite: Klausner, T., Mertens, M., Huntrieser, H., Galkowski, M., Kuhlmann, G., Baumann, R., Fiehn, A., Jöckel, P., Pühl, M., and Roiger, A.: Urban greenhouse gas emissions from the Berlin area: A case study using airborne CO2 and CH4 in situ observations in summer 2018, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3363,, 2020.


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