Toward on-demand measurements of greenhouse gas emissions using an uncrewed aircraft AirCore system

<p>This paper evaluates the performance of a multirotor uncrewed aircraft and AirCore system (UAAS) for measuring vertical profiles of wind velocity (speed and direction) and the mole fractions of methane (CH<span class="inline-formula">₄)</span> and carbon dioxide (CO<span class="inline-formula">₂)</span>, and it presents a use case that combines UAAS measurements and dispersion modeling to quantify CH<span class="inline-formula">₄</span> emissions from a dairy farm. To evaluate the atmospheric sensing performance of the UAAS, four field deployments were performed at three locations in the San Joaquin Valley of California where CH<span class="inline-formula">₄</span> hotspots were observed downwind of dairy farms. A comparison of the observations collected on board the UAAS and an 11 m meteorological tower show that the UAAS can measure wind velocity trends with a root mean squared error varying between 0.4 and 1.1 m s<span class="inline-formula">⁻¹</span> when the wind magnitude is less than 3.5 m s<span class="inline-formula">⁻¹</span>. Findings from UAAS flight deployments and a calibration experiment also show that the UAAS can reliably resolve temporal variations in the mole fractions of CH<span class="inline-formula">₄</span> and CO<span class="inline-formula">₂</span> occurring over periods of 10 s or longer. Results from the UAAS and dispersion modeling use case further demonstrate that UAASs have great potential as low-cost tools for detecting and quantifying CH<span class="inline-formula">₄</span> emissions in near real time.</p>