Wonsik Kim, Jaeil Cho, Daisuke Komori, Masatoshi Aoki, Masayuki Yokozawa, Shinjiro Kanae and Taikan Oki
Release Date: November 10, 2011

Tolerance of eddy covariance flux measurement

Wonsik Kim1), Jaeil Cho2), Daisuke Komori3), Masatoshi Aoki4), Masayuki Yokozawa1), Shinjiro Kanae5) and Taikan Oki3)

1) National Institute for Agro-Environmental Sciences
2) Kasuya Research Forest, Kyushu University
3) Institute of Industrial Science, The University of Tokyo
4) Tokyo University of Agriculture and Technology
5) Tokyo Institute of Technology

(Received: October 27, 2011)
(Accepted for publication: October 28, 2011)

Abstract:
Eddy covariance (EC) flux measurement is the most-used technique for observation of the fluxes of sensible heat, latent heat, and carbon dioxide between the land surface and the atmospheric boundary layer. Despite the availability of plentiful EC data from numerous research projects, it is difficult to make meaningful comparisons of EC at different sites, to validate the models used, and to integrate observed data with models because the uncertainties of the method are inadequately defined. We developed a method to evaluate the uncertainties of the EC method without the need to consider individual site specifications and flux characteristics. We showed that the fractional error φ of EC (i.e., tolerance T) can be separated into random and illegitimate components. T can be used as a scale parameter for spatiotemporal stationarity, and can be defined as a rational function. We demonstrated a practical application of T analyses for two contrasting areas: a low-relief paddy field and an area of more complex land-forms where dramatic wind changes affect fluxes, and showed that T analysis provides an appropriate and effective method to determine the uncertainties in EC.

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To cite this article:
Wonsik Kim, Jaeil Cho, Daisuke Komori, Masatoshi Aoki, Masayuki Yokozawa, Shinjiro Kanae and Taikan Oki: “Tolerance of eddy covariance flux measurement”, Hydrological Research Letters, Vol. 5, pp.73-77, (2011) .

doi:10.3178/hrl.5.73
JOI JST.JSTAGE/hrl/5.73
Copyright (c) 2011 Japan Society of Hydrology and Water Resources