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David Kim-Hak, Derek Fleck, Liam Gannon and Taku Ide

September 21st, 2016

Methane is a potent greenhouse gas that has a short-term global warming impact. It comes from a variety of natural and anthropogenic sources which include wetlands, landfills, oil/gas/coal extraction activities and natural gas distribution leaks. Locating and containing these emissions are critical to minimizing their environmental impacts and economically beneficial when retrieving large fugitive amounts. Generally, methane detection is conducted by making real-time atmospheric measurement and identifying large variations from the typical atmospheric concentration of 2 ppm. The measurement technique is well-developed and includes catalytic sensors and laser analyzers. On other hand, soil emission quantification (flux) is not a direct measurement as it is calculated based on rate of gas accumulation in a known chamber volume. In this case, high-performance analyzers are required to provide high temporal resolution and high-precision in situ measurement of the concentration. Here we present a highly-efficient method of measuring methane emission flux using the latest portable and lightweight Cavity Ring-Down Spectroscopy analyzer and a mobile accumulation chamber. The system enables rapid measurement (~1 minute) in a wide range of emission flux. We will present supplemental data acquired from a soil flux measurement campaign at a coal outcrop site in the Four Corner region