Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 14 8 2010 10.5194/hess-14-1487-2010 http://www.hydrol-earth-syst-sci.net/14/1487/2010/ http://www.hydrol-earth-syst-sci.net/14/1487/2010/hess-14-1487-2010.html http://www.hydrol-earth-syst-sci.net/14/1487/2010/hess-14-1487-2010.pdf 1487 1497 2010-08-06 Analysis of the energy balance closure over a FLUXNET boreal forest in Finland J. M. Sánchez juanmanuel.sanchez@uclm.es V. Caselles E. M. Rubio Applied Physics Department, School of Industrial Engineering, University of Castilla-La Mancha, Av. España s/n, 02071 Albacete, Spain Earth Physics and Thermodynamics Department, University of Valencia, C/ Dr. Moliner 50, 46100 Burjassot (Valencia), Spain Institute of Regional Development, University of Castilla-La Mancha, Av. España s/n, 02071 Albacete, Spain 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. Aurela, M., Tuovinen, J.-P, and Laurila, T.: Carbon dioxide exchange in a subartic peatland ecosystem in northern Europe measured by the eddy covariance technique, J. Geophys. Res., 103, 11289–11301, 1998. Aurela, M., Laurila, T., and Tuovinen, J.-P.: Seasonal CO₂ balances of a subartic mire. J. Geophys. Res., 106, 1623–1638, 2001. Aurela, M., Laurila, T., and Tuovinen, J.-P.: Annual CO₂ balance of a subartic fen in northern Europe: Importance of the winter-time efflux, J. Geophys. Res., 107, 4607, doi:10.1029/2002JD002055, 2002. Aurela, M., Laurila, T., and Tuovinen, J.-P.: The timing of snow melt controls the annual CO₂ balance in a subartic fen, Geophys. Res. Letter, 31, L16119, doi:10.1029/2004GL020315, 2004. Barr, A. G., Morgenstern, K., Black, T. A., McCaughey, J. H., and Nesic, Z.: Surface energy balance closure by the eddy-covariance method above three boreal forest stands and implications for the measurement of the CO₂ flux, Agric. For. Meteorol., 140, 322–337, 2006. Blanken, P. D., Black, T. A., Yang, P. C., Neumann, H. H., Nesic, Z., Staebler, R., den Hartog, G., and Novak, M. D., and Lee, X.: Energy balance and canopy conductance of a boreal aspen Forest: partitioning overstory and understory components, J. Geophys. Res., 102, 28915–28927, 1997. Cava, D., Contini, D., Donateo, A., and Martano, P.: Analysis of short-term closure of the surface energy balance above short vegetation, Agric. For. Meteorol., 148, 82–93, 2008. Culf, A. D., Foken, T., and Gash, J. H. C.: The energy balance closure problem, in: A new perspective on an iteractive system, edited by: Kabat, P., Claussen, M., Vegetation, Water, Humans and the Climate, Springer, Berlin, pp. 159–166, 2004. Falge, E., Baldocchi, D., Olson, R. J., Anthoni, P., Aubinet, M., Bernhofer, C., Burba, G., Ceulemans, R., Clement, R., Dolman, H., Granier, A., Gross, P., Grünwald, T., Hollinger, D., Jensen, N.-O., Katul, G., Keronen, P., Kowalski, A., Ta Lai, C., Law, B. E., Meyers, T., Moncrieff, J., Moors, E., Munger, J.W., Pilegaard, K., Rannik, Ãœ., Rebmann, C., Suyker, A., Tenhunen, J., Tu, K., Verma, S., Vesala, T., Wilson, K., and Wofsy., S.: Gap filling strategies for defensible annual sums of net ecosystem exchange. Agric. For. Meteorol., 107, 43–69, 2001. Foken, T., Wimmer, F., Mauder, M., Thomas, C., and Liebethal, C.: Some aspects of the energy balance closure problem, Atmos. Chem. Phys., 6, 4395–4402, doi:10.5194/acp-6-4395-2006, 2006. Foken, T.: The energy balance closure problem: an overview, Ecol. Appl., 18, 1351–1368, 2008. Finnigan, J.: The storage term in eddy flux calculations, Agric. For. Meteorol., 136, 108–113, 2006. Gao, Z., Lenschow, D. H., He, Z., and Zhou, M.: Seasonal and diurnal variations in moisture, heat and CO₂ fluxes over a typical steppe prairie in Inner Mongolia, China, Hydrol. Earth Syst. Sci., 13, 987–998, doi:10.5194/hess-13-987-2009, 2009. Garratt, J. R.: The Atmospheric Boundary Layer. Cambridge University Press, Cambridge, 316 pp., 1992. Haslwanter, A., Hammerle, A., and Wohlfahrt, G.: Open-path vs. Closed-path eddy covariance measurements of the net ecosystem carbon dioxide and water vapour exchange: A long-term perspective, Agric. For. Meteorol., 149, 291–302, 2009. Horst, T. W.: On frequency response corrections for eddy covariance flux measurements. Bound-Layer Meteorol., 94, 517–520, 2000. Ibrom, A., Dellwik, E., Flyvbjerg, H., Jensen, N. O., and Pilegaard, K.: Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy covariance systems, Agric. For. Meteorol., 147, 140–156, 2007. Lee, X. H., Yu, Q., Sun, X. M., Liu, J. D., Min, Q. W., Liu, Y. F., and Zhang, X. Z.: Micrometeorological fluxes under the influence of regional and local advection: a revisit, Agric. For. Meteorol., 122, 111–124, 2004. Liu, S., Bai, J., Jia, Z., Jia, L., Zhou, H., and Lu, L.: Estimation of evapotranspiration in the Mu Us Sandland of China, Hydrol. Earth Syst. Sci., 14, 573–584, doi:10.5194/hess-14-573-2010, 2010. Ma, Y., Wang, Y., Wu, R., Hu, Z., Yang, K., Li, M., Ma, W., Zhong, L., Sun, F., Chen, X., Zhu, Z., Wang, S., and Ishikawa, H.: Recent advances on the study of atmosphere-land interaction observations on the Tibetan Plateau, Hydrol. Earth Syst. Sci., 13, 1103–1111, doi:10.5194/hess-13-1103-2009, 2009. Malhi, Y., Nobre, A. D., Grace, J., Kruijt, B., Pereira, M. G. P., Culf, A., and Scott, S.: Carbon dioxide transfer over a Central Amazonian rain forest, J. Geophys. Res., 103(24), 31593–31612, 1998. Massman, W. J.: A simple method for estimating frequency response corrections for eddy covariance systems, Agric. For. Meteorol., 104, 185–198, 2000. Massman, W. J. and Ibrom, A.: Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow, Atmos. Chem. Phys., 8, 6245–6259, doi:10.5194/acp-8-6245-2008, 2008. Meijninger, W. M. L. and de Bruin, H. A. R.: The sensible heat fluxes over irrigated areas in western Turkey determined with a large aperture scintillometer, J. Hydrol., 229, 42–49, 2000. McCaughey, J. H.: Energy balance storage terms in a mature mixed forest at Petawawa, Ontario – A case study. Bound-Layer Met., 31, 89–101, 1985. McMillen, R. T.: A BASIC program for eddy correlation in non-simple terrain, NOAA Tech. Memo. ERL ARL-147, NOAA Environ. Res. Lab., Silver Spring, Md, 1986. McMillen, R. T.: An eddy correlation technique with extended applicability to non-simple terrain, Boundary-Layer Meteorol., 43, 213–245, 1988. Moore, C. J.: Frequency response corrections for eddy correlation systems, Bound.-Lay. Meteorol., 37, 17–35, 1986. Moreno, J., Laurila, T., and Moya, I.: Solar Induced Fluorescence Experiment (Final Report), ESA, Noodwijk, Holland, 2002. Oliphant, A. J., Grimmond, C. S. B., Zutter, H. N., Schmid, H. P., Su, H.-B., Scott, S. L., Offerle, B., Randolph, J. C., and Ehman, J.: Heat storage and energy balance fluxes for a temperate deciduous forest, Agric. For. Meteorol., 126, 185–201, 2004. Oncley, S.P., Foken, T., Vogt, R., Kohsiek, W., De Bruin, H., Bernhofer, C., Christen, A., Grantz, D., LEhner, E., Liebetahl, C., Liu, H., Mauder, M., Pitacco, A., Ribeiro, L., and Weidinger, T.: The energy balance experiment EBEX-2000, Part I: Overview and energy balance, Bound.-Lay. Meteorol., 123, 1–28, 2007. Sakai, R. K., Fitzjarrald, D. R., and Moore, K. E.: Importance of low-frequency contributions to eddy fluxes observed over rough surfaces. J. Appl. Meteorol., 40, 2178–2192, 2001. Sánchez, J. M., Caselles, V., Niclòs, R., Coll, C., and Kustas, W. P.: Estimating energy balance fluxes above a boreal forest from radiometric temperature observations, Agric. For. Meteorol., 149, 1037–1049, 2009. Schmid, H. P., Cleugh, H. A., Grimmond, C. S. B., and Oke, T. R.: Spatial variability of energy fluxes in suburban terrain, Bound-Lay. Meteorol., 54, 249–276, 1991. Schmid, H. P.: Source areas for scalars and scalar fluxes, Bound-Lay. Meteorol., 67, 293–318, 1994. Soegaard, H., Jensen, N. O., Boegh, E., Hasager, C. B., Schelde, K., and Thomsen, A.: Carbon dioxide exchange over agricultural landscape using eddy correlation and footprint modelling, Agr. Forest Meteorol., 114, 153–173, 2003. Su, Z., Timmermans, W. J., van der Tol, C., Dost, R., Bianchi, R., Gómez, J. A., House, A., Hajnsek, I., Menenti, M., Magliulo, V., Esposito, M., Haarbrink, R., Bosveld, F., Rothe, R., Baltink, H. K., Vekerdy, Z., Sobrino, J. A., Timmermans, J., van Laake, P., Salama, S., van der Kwast, H., Claassen, E., Stolk, A., Jia, L., Moors, E., Hartogensis, O., and Gillespie, A.: EAGLE 2006 – Multi-purpose, multi-angle and multi-sensor in-situ and airborne campaigns over grassland and forest, Hydrol. Earth Syst. Sci., 13, 833–845, doi:10.5194/hess-13-833-2009, 2009. Tanaka, H., Hiyama, T., Kobayashi, N., Yabuki, H., Ishii, Y., Desyatkin, R. V., Maximov, T. C., and Ohta, T.: Energy balance and its closure over a young larch forest in eastern Siberia, Agric. For. Meteorol., 148, 1954–1967, 2008. Timmermans, W. P., Su, Z., and Olioso, A.: Timmermans, W. J., Su, Z., and Olioso, A.: Footprint issues in scintillometry over heterogeneous landscapes, Hydrol. Earth Syst. Sci., 13, 2179–2190, doi:10.5194/hess-13-2179-2009, 2009. Twine, T. E., Kustas, W. P., Norman, J. M., Cook, D. R., Houser, P. R., Meyers, T. P., Prueger, J. H., Starks, P. J., and Wesely, M. L.: Correcting eddy-covariance flux underestimates over a grassland, Agric. For. Meteorol., 103 (3), 279–300, 2000. Tuovinen, J.-P., Aurela, M., and Laurila, T.: Comparison of different coordinate systems for Eddy covariance measurements. In: ACCENT-BIAFLUX Workshop 2005, Trace gas and aerosol flux measurement and techniques, Riso National Laboratory, Roskilde, Denmark, 2005. van der Kwast, J., Timmermans, W., Gieske, A., Su, Z., Olioso, A., Jia, L., Elbers, J., Karssenberg, D., and de Jong, S.: Evaluation of the Surface Energy Balance System (SEBS) applied to ASTER imagery with flux-measurements at the SPARC 2004 site (Barrax, Spain), Hydrol. Earth Syst. Sci., 13, 1337–1347, doi:10.5194/hess-13-1337-2009, 2009. van der Tol, C., van der Tol, S., Verhoef, A., Su, B., Timmermans, J., Houldcroft, C., and Gieske, A.: A Bayesian approach to estimate sensible and latent heat over vegetated land surface, Hydrol. Earth Syst. Sci., 13, 749–758, doi:10.5194/hess-13-749-2009, 2009. Wen, J., Wang, L., and Wei, Z. G.: An overview of the LOess Plateau mesa region land surface process field EXperiment series (LOPEXs), Hydrol. Earth Syst. Sci., 13, 945–951, doi:10.5194/hess-13-945-2009, 2009. Were, A., Villagarcía, L., Domingo, F., Alados-Arboledas, L., and Puigdefábregas, J.: Analysis of effective resistance calculation methods and their effect on modelling evapotranspiration in two different patches of vegetation in semi-arid SE Spain, Hydrol. Earth Syst. Sci., 11, 1529–1542, doi:10.5194/hess-11-1529-2007, 2007. Wilczak, J. M., Oncley, S. P., and Stage, S. A.: Sonic anemometer tilt correction algorithms, Bound-Layer Met., 99, 127–150, 2001. Wilson, K., Goldstein, A., Falge, E., Aubinet, M., Baldocchi, D., Berbigier, P., Bernhofer, C., Ceulemans, R., Dolman, H., Field, C., Grelle, A., Ibrom, A., Law, B. E., Kowalski, A., Meyers, T., Moncrieff, J., Monson, R., Oechel, W., Tenhunen, J., Valentini, R., and Verma, S.: Energy balance closure at FLUXNET sites, Agric. For. Meteorol., 113, 223–243, 2002. Wu, J., Guan, D., Han, S., Shi, T., Jin, C., Pei, T., and Yu, G.: Energy Budget above a temperate mixed forest in northeastern China, Hydrol. Process., 21, 2425–2434, 2007. Xin, X. and Liu, Q.: The Two-layer Surface Energy Balance Parameterization Scheme (TSEBPS) for estimation of land surface heat fluxes, Hydrol. Earth Syst. Sci., 14, 491–504, doi:10.5194/hess-14-491-2010, 2010.