Quantifying methane emissions from the energy and agriculture sectors using vehicle and UAV-based atmospheric observations

To mitigate climate change and reduce greenhouse gas emissions, it is crucial to understand and quantify methane (CH4) emissions. This thesis explores the application of two mobile platforms – a mobile van and an unmanned aerial vehicle (UAV) – combined with a highly precise sampling tool to measure and quantify CH4 emissions from the energy and agricultural sectors. It starts by investigating and quantifying CH4 emissions at the source and facility levels from a large oil and natural gas region in Romania, combining different ground-based techniques. Furthermore, the thesis includes measurements and quantification of the whole-farm CH4 emissions from a single dairy cow farm. In addition, after subtracting the estimated manure emission factor, the CH4 enteric emission factor from the ruminant digestion process is derived. Lastly, a methodology is developed to rapidly estimate whole-farm CH4 emissions from a large number of dairy cow farms using single-transect mobile van-based atmospheric observations. The findings from this thesis indicate that (1) Romania's oil and natural gas infrastructure holds substantial potential for mitigation, (2) quantifying whole-farm CH4 emissions and the CH4 enteric emission factor from a single farm is achievable using the innovative UAV technique, and the estimate uncertainty can be reduced by improved onsite wind measurements or combining with a tracer ratio method (3) rapid estimation of the whole-farm CH4 emissions from a large number of dairy cow farms is feasible.