New streamlined, reduced-cost CO2/H2O Flux Sensor & Node open a new era for eddy covariance measurements and applications

From academic research to carbon MMRV/MRV/dMRV/aMRV frameworks and across many industrial sectors, high-quality direct measurements of CO₂ fluxes between the earth surface and the atmosphere are emerging as strategic assets of unique usefulness. Correspondingly, demand for simple-to-use automated instrumentation to perform such measurements is growing fast.

The LI-720 is a new CO₂/H₂O “flux sensor”, designed to achieve performances comparable to traditional high-end EC systems but at significantly reduced costs, maintenance needs, and power consumption. Recently, LI-COR Environmental released the Carbon Node, which combines the LI-720 with a power/IoT communication box. The result is a wireless, lightweight instrument more akin to a meteorological sensor than to a traditional EC system, which delivers flux data directly to a cloud-based data management system where flux time series are further consolidated with automatic quality control and gap-filling procedures. The Carbon Node represents the most streamlined CO₂/H₂O flux system available to date.

Here we present the technical features of this new system and showcase its field performance against high-end EC systems across a variety of ecosystems and climates, discussing benefits, trade-offs and limitations. We find that, when unit-to-unit variability and other uncertainties are taken into account, the LI-720 performance is comparable to traditional open-path (LI-7500-based) and enclosed-path (LI-7200-based) EC systems, most notably when fluxes are aggregated over daily, weekly or monthly cumulates.

We also discuss the use of the new sensor in both traditional academic applications focused on process-level studies, and new commercial applications focused on decision-making for immediate societal benefits.