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±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.
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
