Abstract
A severe reduction of greenhouse gas emissions is necessary to reach the objectives of the Paris Agreement. The implementation and continuous evaluation of mitigation measures requires regular independent information on emissions of the two main anthropogenic greenhouse gases, carbon dioxide (CO2) and methane (CH4). Our aim is to employ an observation-based method to determine regionalscale greenhouse gas emission estimates with high accuracy. We use aircraft-and ground-based in situ observations of CH4, CO2, carbon monoxide (CO), and wind speed from two research flights over the Upper Silesian Coal Basin (USCB), Poland, in summer 2018. The flights were performed as a part of the Carbon Dioxide and Methane (CoMet) mission above this European CH4 emission hot-spot region. A kriging algorithm interpolates the observed concentrations between the downwind transects of the trace gas plume, and then the mass flux through this plane is calculated. Finally, statistic and systematic uncertainties are calculated from measurement uncertainties and through several sensitivity tests, respectively. For the two selected flights, the in-situ-derived annual CH4 emission estimates are 13.8±4.3 and 15.1±4.0 kg s-1, which are well within the range of emission inventories. The regional emission estimates of CO2, which were determined to be 1.21 ± 0.75 and 1.12 ± 0.38 t s-1, are in the lower range of emission inventories. CO mass balance emissions of 10.1±3.6 and 10.7±4.4 kg s-1 for the USCB are slightly higher than the emission inventory values. The CH4 emission estimate has a relative error of 26 %-31 %, the CO2 estimate of 37 %-62 %, and the CO estimate of 36 %-41 %. These errors mainly result from the uncertainty of atmospheric background mole fractions and the changing planetary boundary layer height during the morning flight. In the case of CO2, biospheric fluxes also add to the uncertainty and hamper the assessment of emission inventories. These emission estimates characterize the USCB and help to verify emission inventories and develop climate mitigation strategies.
| Original language | English |
|---|---|
| Article number | 652 |
| Pages (from-to) | 12675-12695 |
| Number of pages | 21 |
| Journal | Atmospheric Chemistry and Physics |
| Volume | 20 |
| Issue number | 21 |
| DOIs | |
| Publication status | Published - 3 Nov 2020 |
Funding
Acknowledgements. The authors especially thank DLR-FX for the campaign cooperation, especially the pilots Thomas van Mar-wick and Philipp Weber and the group of Ralph Helmes, Andreas Giez, Martin Zöger and Martin Sedlmeir. We would like to thank Joseph Pitt for providing an updated version of the kriging package and giving advice on its usage. We acknowledge funding for the CoMet campaign by BMBF (German Federal Ministry of Education and Research) through AIRSPACE. We thank DLR VOR for funding the young investigator research group “Greenhouse Gases”. The ground-based measurements on vehicles were funded by the European Union’s Horizon 2020 Research and Innovation program under the Marie Skłodowska-Curie ITN project Methane goes Mobile – Measurements and Modelling (MEMO2; https:// h2020-memo2.eu/, last access: 22 October 2020). The authors acknowledge ECCAD for archiving and distributing the CAMS emission inventories. Financial support. This research has been supported by the BMBF (grant nos. FKZ 01LK1701A and FKZ 01LK1701C), the EU Horizon 2020 MEMO2 (grant no. 722479), and the Deutsche Forschungsgemeinschaft (DFG) Priority Program SPP 1294.
