LI-7700 Performance Data

The following data are excerpts from a poster presented at AmeriFlux in 2011.
arrow Click here to view the poster in its entirety.

Frequency Response

Spectral and co-spectral analysis is a powerful tool to evaluate the performance of an eddy covariance flux system, more specifically the performance of the sonic anemometer and the gas analyzer. As shown below, the normalized power spectrum of the LI-7700 follows the theoretic curve indicating that the LI-7700 has sufficient resolution and response time for eddy covariance flux measurements.

frequency-response-graphs

Zero-flux test: ensemble averaged hourly flux, Nebraska

The data below is from a methane eddy-covariance flux system at a zero flux site. Chamber-based soil methane emission measurements over a few years at this site show no methane emission.

zero-flux-test

For additional information on the performance of the LI-7700, view the following publications:

McDermitt D., G. Burba, L. Xu, T. Anderson, A. Komissarov, B. Riensche, J. Schedlbauer, G. Starr, D. Zona, W. Oeschel, S. Oberbauer, and S. Hastings, 2010. A new low-power, open-path instrument for measuring methane flux by eddy covariance. Applied Physics B: Lasers and Optics, 102: 391-405.

Matteo D., J. Verfaillie, F. Anderson, L. Xu, D. Baldocchi. 2011. Comparing laser-based open- and closed-path gas analyzers to measure methane fluxes using the eddy covariance method. Agricultural and Forest Meteorology, 151: 1312-1324.


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