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| Titel |
Analysis of the energy balance closure over a FLUXNET boreal forest in Finland |
| VerfasserIn |
J. M. Sánchez, V. Caselles, E. M. Rubio |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 8 ; Nr. 14, no. 8 (2010-08-06), S.1487-1497 |
| Datensatznummer |
250012395
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| Publikation (Nr.) |
 copernicus.org/hess-14-1487-2010.pdf |
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| Zusammenfassung |
| The imbalance in the surface energy budget, when using eddy-covariance
techniques to measure turbulent fluxes, is still an unresolved problem.
Important progresses have been reported in recent years identifying
potential reasons for this lack of energy balance closure. In this paper we
focus on the data collected in a FLUXNET boreal forest site in
Sodankylä, Finland. Using one month half-hourly data, an average Energy
Balance Ratio (EBR) of 0.72 is obtained. The inclusion of the heat storage
terms in the energy budget yields an improvement of about 6% in the total
closure. The sensitivity of the energy balance closure to the turbulence
intensity is analysed in terms of the friction velocity, and atmospheric
stability/instability conditions. Significant better closure is obtained for
high values of the friction velocity and unstable conditions. The mismatch
in variable footprints for different fluxes is checked by analysing the
dependence of the closure on wind direction. The inhomogeneities of the
emplacement surrounding the flux tower induce a critical decrease in the EBR
of up to 30% for specific wind directions. After filtering all
unfavourable conditions, EBR=0.94. This is a reasonable good result for the
energy balance closure. However there is still a 6% of the available
energy unaccounted. Part of this remaining imbalance could be justified as
the impossibility of the 30 min averaging time to capture the low frequency
flux contributions, since the closure is improved by a 5% when the
averaging time is expanded to 2 h. |
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