Airborne imaging of methane concentrations from a controlled release experiment using the imaging spectrometer AVIRISng

Background/Question/Methods

Reducing emissions from concentrated sources is a particularly efficient means of mitigating their effects given stationary point sources produce the majority of U.S. anthropogenic greenhouse gas emissions. Methane (CH₄) emissions have large uncertainties and presently the majority is attributed to anthropogenic sources that are projected to increase. Airborne imaging spectrometers are well suited for monitoring local sources by covering large regions with the high spatial resolution necessary to resolve emissions. In this study, a quantitative methane retrieval using Differential Optical Absorption Spectroscopy and Singular Value Decomposition was developed for use with data from the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng).

Results/Conclusions

As part of a field campaign with controlled methane releases at the Rocky Mountain Oilfield Testing Center (RMOTC), a number of methane plumes were clearly visible at multiple flux rates and flight altitudes. Plumes appeared consistent with wind directions measured at ground stations and extended up to 150 m downwind of the release point. This controlled release experiment was used to assess the methane sensitivity of AVIRISng and inform sensor design for future imaging spectrometers that could constrain natural and anthropogenic methane emissions on local and regional scales. Therefore, imaging spectrometers permit direct attribution of emissions to individual point sources which is particularly useful given the large uncertainties associated with anthropogenic emissions, including industrial point source emissions and fugitive methane from the oil and gas industry.