Use of UAVs for greenhouse gas monitoring at hotspot emissions zones

Abstract:

Measuring greenhouse gas emissions from individual localised sources, or "hotspots", is important for both compliance monitoring and validating the techniques used to compile national emission inventories. Frequently ground based techniques are used, such as flux chamber measurements, which suffer from issues regarding sample representativeness, and tracer release methods, which for area sources rely heavily on release site configuration. Obtaining vertically resolved data can enable the use of a mass balance method to calculate greenhouse gas fluxes. This has been achieved using remote sensing techniques, but this usually requires the deployment of expensive, bulky instrumentation.

Here we evaluate the suitability of using UAVs, in conjunction with emerging miniaturised sensor technology, as a highly manoeuvrable, low cost alternative for measuring hotspot greenhouse gas emissions. We describe a case study performed at a UK landfill site, where greenhouse gas measurements made on board a fixed wing UAV were used to estimate the bulk CH₄ emission rate. Details of the mass balance technique employed, along with the key uncertainties associated with it, are discussed. This work is part of an ongoing study at the University of Manchester into the application of UAVs in atmospheric research, with the rapid advancement in miniaturised sensor technology providing new opportunities for integrating trace gas measurement with existing lightweight UAVs.