Marvin Knapp and co-workers demonstrate the capabilities of a hyperspectral camera for imaging CH4 (and CO2) exhaust plumes from localized emission sources. For the demonstrator study, they deployed the hyperspectral camera in 1 km distance from a ventilation facility of a coal mine in the Upper Silesian Coal Basin, Poland. While scanning the sky above the facility, the camera was able to catch the CH4 exhaust plume emanating from the facility with 1 min temporal resolution. Emission rates were found exceeding 1 ton of CH4 per hour with large variability on all observed time scales. Error bars were on the order of a few hundred kg per hour. The hyperspectral camera is based on a grating spectrometer for the shortwave-infrared and a 2D detector, that simultaneously records skylight absorption spectra for a vertical column above the target. Scanning the camera horizontally across the target yields images of the scene and for each pixel the CH4 column enhancement. Combining these CH4 images produces videos of the turbulent CH4 dispersion out of the ventilation facility.
Knapp, M., Scheidweiler, L., Külheim, F., Kleinschek, R., Necki, J., Jagoda, P. and Butz, A.: Spectrometric imaging of sub-hourly methane emission dynamics from coal mine ventilation, Environ. Res. Lett., 18(4), 044030, doi:10.1088/1748-9326/acc346, 2023.
(For videos, see supplementary data of the above publication.)