MAMAP - CoMet Proposal for the University of Bremen contribution to the HALO Mission CoMet in the framework of the DFG Priority Program Atmosphären- und Erdsystemforschung mit dem Forschungsflugzeug HALO (SPP 1294)
Final Report Abstract
The CoMet research campaign was a multi-instrument and multi-platform activity of different national and international universities and research institutes conducted in 2018. Aim of the investigations was the determination of the emissions from the two CO2 emitting power plants Jänschwalde in Germany and Belchatow in Poland, and of Europe’s CH4 emission hot spot in the Upper Silesian Coal Basin (USCB) in Poland. Additionally, synergies between the different airborne remote sensing instruments and the airborne in-situ data should be analysed and if applicable also a comparison to satellite data should be conducted. Within this project, the focus was the analysis and interpretation of the data from the passive airborne remote sensing instrument MAMAP, which was installed aboard a low and slow flying Cessna aircraft (compared to the high and fast flying HALO aircraft) operate by the FUB Berlin. Observations and/or model data from other groups were used to improve the data analysis or to support the interpretation of the results where appropriate. In total, the MAMAP system acquired observations during 8 flights through the course of about 2 weeks. In the complex source region of USCB, where CH4 is emitted from over 50 coal mine ventilation shafts distributed over an area of around 60 x 40 km², it turned out that, for example, the more manoeuvrable Cessna aircraft enabled much denser flight patterns (compared to HALO). Consequently, emissions from different shaft clusters were disentangled and analysed. Furthermore, because, for some shaft clusters the observed fluxes could be separated, it was also possible to compare those fluxes to not only to the reported annual emissions, but also to hourly data. The analysis of the hourly data and the comparison showed that the coal mining emissions in USCB vary significantly throughout a year and even from hour-to-hour. Therefore, caution is not only required if observations from different instruments are compared, which were not acquired at approximately the same time, but also if observations are compared to the usually available annually reported data. The analysis of the power plant data revealed another important point, which is also relevant for the coal mining emissions. Even if the strength of an emission source were constant, atmospheric turbulence could swirl plume structures significantly. For the case, that the instruments did not fly on the same aircraft guaranteeing that they observe the exact same scene at the same time, comparisons are only possible in a statistical way. For the power plant Jänschwalde, the averaged fluxes derived from the MAMAP and CHARM-F cross-sections are actually close to the reported annual emission of 22.8 MtCO2/yr. The single fluxes, however, vary between 16 to 34 MtCO2/yr and 13 to 30 MtCO2/yr for MAMAP and CHARM-F, respectively. Additionally, that effect appears to be more pronounced in the afternoon than before noon. Most of the flights in the USCB were conducted before or around noon. This was not only related to the less expected turbulence before noon but also to the fact that after noon cloud formation set in prohibiting measurements with passive remote sensing instruments. Unfortunately, the TROPOMI instrument aboard the Sentinel-5 Precursor satellite has a local overpass time in the early afternoon at 13:30. However, at that time, the USCB is usually cloud covered. Nevertheless, the satellite was also used in a mass balance approach to estimate the emissions from the USCB. From the experience gained and summarised above, it can be concluded that passive remote sensing of greenhouse gases can be interpreted easier in case of relatively stable weather conditions, which for Europe appear typically in the morning. Therefore, future satellite sensors like Sentinel-5 and CO2M both flying in a morning orbit, will yield a better return w.r.t. the number of useful measurements to estimate emissions. For the future, it is planned to perform a more rigorous comparison between passive and active remote sensing observations. Therefore, both instruments are foreseen to fly on the HALO aircraft during the CoMet 2.0 campaign in 2022 to investigate emissions in the US and in Canada.
Publications
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Quantification of CH4 coal mining emissions in Upper Silesia by passive airborne remote sensing observations with the MAMAP instrument during CoMet, Atmospheric Chemistry and Physics Discuss.
Krautwurst, S., Gerilowski, K., Borchardt, J., Wildmann, N., Galkowski, M., Swolkien, J., Marshall, J., Fiehn, A., Roiger, A., Ruhtz, T., Gerbig, C., Necki, J., Burrows, J. P., Fix, A., and Bovensmann, H.
