UAV-based methane emission quantification at a UK landfill site

A field campaign using UAV-based measurements to derive methane fluxes from a large landfill site in North Manchester was conducted in the summer of 2022. The system comprises the newly developed ABB lightweight (3kg) Hoverguard greenhouse gas analyser based on the off-Axis Integrated Cavity Output Spectroscopy (with a precision of 0.9 ppb for CH4 at 1 Hz), an on-board TriSonica™ Mini wind sensor and the DJI M600 pro hexacopter.  Fluxes and corresponding flux uncertainties were calculated using the mass-balance method from 6 flight surveys conducted downwind of the active landfill. Accurate and reliable wind measurements sampled from instrumentation onboard rotary-wing UAVs remains a challenge, which was found to dominate flux uncertainty in this study. This study presents a low-cost and repeatable methodology for hotspot methane emission quantification.