For methane mitigation strategies to be successful they must be based on accurate and spatially resolved flux estimates, not only from global observations from satellite-borne instruments, but also from source-specific measurements. The need for improved accuracy and spatial resolution down to facility scale remains acute.

Laser Dispersion Spectroscopy (LDS) provides continuous <5 ppb precision measurements in real time across an area of ~ 1 km² in almost all weather conditions. By virtue of the integrated multi-beam open path measurements, the turbid variations observed at a single point are greatly smoothed, providing a more spatially representative measurement.

We will present data collected continuously for a period of >six months in rural England, providing multi-scale temporal data through a range of environmental conditions. The instrument allows for the estimation of diffuse fluxes of a few micrograms/s/m² using nocturnal inversion layer trapping, where no point sources are present.