Fugitive methane detection using open-path stand-off chirped laser dispersion spectroscopy.

Area of Science:

• Atmospheric science
• Spectroscopy
• Environmental monitoring

Background:

• Accurate detection of atmospheric methane is crucial for environmental monitoring and climate change studies.
• Existing methods for methane detection often require close proximity or are limited in scope.
• Development of remote sensing technologies for methane is an active area of research.

Purpose of the Study:

• To develop and validate an open-path chirped laser dispersion spectrometer for stand-off methane detection.
• To integrate simultaneous ranging for variable optical pathlength measurements.
• To assess the instrument's performance in laboratory and field conditions for fugitive methane emission monitoring.

Main Methods:

• Utilized an open-path chirped laser dispersion spectrometer with two distinct operation modes.
• Integrated simultaneous ranging for precise optical pathlength determination.
• Conducted controlled methane release experiments and field deployment near a natural gas compressor station.

Main Results:

• Achieved a sensitivity of 2.9 ppm-m/Hz^1/2 and pathlength precision of 0.2 m/Hz^1/2.
• Successfully detected methane plumes in a field deployment.
• Narrowed down methane plume locations using multi-path measurements, verified by a reference sensor.

Conclusions:

• The developed spectrometer is effective for stand-off detection of atmospheric methane.
• The instrument's ranging capability enhances concentration measurements over varying pathlengths.
• This technology shows promise for identifying fugitive methane emissions from industrial sources.