Estimating CH<sub>4</sub>, CO<sub>2</sub>, and CO emissions from coal mining and industrial activities in the Upper Silesian Coal Basin using an aircraft-based mass balance approach

Abstract

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 regional-scale 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 ± 3.6 kg/s and 15.1 ± 3.0 kg/s, which is well within the range of emission inventories. The regional emission estimates of CO2, which were determined to be 1.21 ± 0.72 t/s and 1.12 ± 0.37 t/s, are in the lower range of emission inventories. CO mass balance emissions of 10.1 ± 3.2 kg/s and 10.7 ± 2.9 kg/s for the USCB are slightly higher than the emission inventory values. The CH4 emission estimate has a relative error of 21–26 %, the CO2 estimate of 33–60 %, and the CO estimate of 27–32 %. 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.

Estimating Upper Silesian coal mine methane emissions from airborne in situ observations and dispersion modeling

“…Differences in estimated and reported emission rates are however expected due to the comparison of instantaneous estimates and yearly averages. This is in line with previous studies hinting towards EDGAR v4.3.2 overestimating CH 4 emissions in the USCB (Luther et al (2019); Fiehn et al (2020)). Uncertainty estimates include systematic contributions from ensemble runs and statistical uncertainty introduced by the fitting algorithm.…”

Estimating CH<sub>4</sub>, CO<sub>2</sub> and CO emissions from coal mining and industrial activities in the Upper Silesian Coal Basin using an aircraft-based mass balance approach

“…Data availability. The data are accessible on the ICOS ERIC -Carbon Portal under https://doi.org/10.18160/0SFH-JJ93 (Fiehn et al, 2020).…”

Quantification of CH<sub>4</sub> coal mining emissions in Upper Silesia by passive airborne remote sensing observations with the MAMAP instrument during CoMet

“…2). Additional observations comprised airborne in situ concentrations of CH 4 and CO 2 by the FUB Cessna, by the HALO aircraft, and by a second Cessna Caravan (also operated by the DLR, Fiehn et al, 2020;Kostinek et al, 2019). The airborne observations were complemented by on ground measurements of in situ concentrations of CH 4 and CO 2 by mobile vans (operated by AGH Krakow, IUP Heidelberg, and Utrecht University as part of the MEMO2 3 activities), stationary and mobile CH 4 column observations by FTS (operated by DLR, Luther et al, 2019), and wind field observations by three stationary wind lidars in that region specifically deployed for CoMet (operated by DLR, Wildmann et al, 2020).…”

“…This can be achieved for airborne in situ measurements, if the aircraft is equipped with the adequate instrumentation. In this case, trace gas and wind information are directly measured along the flight track while crossing the plume (e.g., Fiehn et al, 2020;Pitt et al, 2019;Ren et al, 2019;Peischl et al, 2018;Gordon et al, 2015). Since the MAMAP instrument needs to fly above the PBL, alternative sampling strategies for the wind field have been investigated in the past.…”

“…Comparisons to annually reported emissions of single shafts or small clusters must be handled with caution and are hardly meaningful due to the high variability of the emissions. On larger scales, as for example investigated in Fiehn et al (2020) who analyzed airborne in situ observations covering the entire basin, fluctuations of emissions from single shafts or even mines might cancel out.…”