Methane observations across US eco-climates using existing NEON infrastructure

At 47 terrestrial sites across the North American continent, the National Ecological Observatory Network (NEON) measures vertical profiles of CO₂ concentrations. These include measurements of the stable isotopic signatures of δ¹³C in CO₂ in the atmosphere with a sensor (G2131-i, Picarro Inc.) that is also capable of measuring the concentration of methane (CH₄).

By taking advantage of this existing system, here we propose (i) a cost-efficient solution to measure CH₄ concentration along a vertical profile and (ii) sensor calibration and field validation strategies. We (iii) solicit discussion on various approaches to calculate CH₄ flux based on concentration profile measurements. Collaborating with other flux networks such as AmeriFlux and FLUXNET, NEON would submit the data into a global database of CH₄ flux observations. This will broaden the coverage of CH₄ flux across the North American continent, in particular at upland sites that to date are assumed to be net sinks.