Impact of canopy aerodynamic distance spatial and temporal variability on long term eddy covariance measurements

[en] Understanding if and how the spatial and temporal variability of the surrounding environment affects turbulence is essential for long-term eddy covariance measurements. It requires characterizing the surrounding environment. One way to achieve this is to analyse the canopy aerodynamic distance (Δ), which is the difference between measurement height (zm) and displacement height (d). In this work, an original method to estimate the canopy aerodynamic distance at a fine spatial (30° sectors) and temporal (one year) resolution was proposed. It was based on sensible heat cospectra analysis, calibrated on a measurement height change and validated using canopy height inventories. This method was applied to 20 years of eddy covariance measurements from the Vielsalm Terrestrial Observatory (VTO), a site located in a mixed temperate forest. The method allowed Δ spatio-temporal variability due to changes in canopy or measurement height to be detected. Relationships between Δ and turbulence statistics were then analysed: the momentum correlation coefficient (ruw) was found to be dependent on Δ, confirming that the measurements were made in the roughness sublayer of the atmospheric surface layer. In contrast, no such relationship was found sensible heat, CO2 or water vapour correlation coefficients, suggesting that the Δ variability did not affect significantly these fluxes. There were significant differences, however, between azimuthal directions, suggesting that these scalars were affected by forest heterogeneity in a different way. Various hypotheses were put forward to explain the differences and their relevance was evaluated. This study highlighted the need to consider the spatial and temporal variability of the surrounding environment in order to verify the consistency of long-term eddy covariance datasets.

Research Center/Unit :

TERRA Research and Teaching Centre - TERRA

Disciplines :

Environmental sciences & ecology

Author, co-author :

Hurdebise, Quentin ; Université de Liège > Ingénierie des biosystèmes (Biose) > Biosystems Dynamics and Exchanges

Heinesch, Bernard ; Université de Liège > Ingénierie des biosystèmes (Biose) > Biosystems Dynamics and Exchanges

De Ligne, Anne ; Université de Liège > Ingénierie des biosystèmes (Biose) > Biosystems Dynamics and Exchanges

Vincke, Caroline

Aubinet, Marc ; Université de Liège > Ingénierie des biosystèmes (Biose) > Biosystems Dynamics and Exchanges

Language :

English

Title :

Impact of canopy aerodynamic distance spatial and temporal variability on long term eddy covariance measurements

Alternative titles :

[fr] Impact de la distance aérodynamique entre la canopée et le système de mesure sur les longues séries temporelles obtenues par covariance de turbulence

Publication date :

08 August 2017

Journal title :

Agricultural and Forest Meteorology

ISSN :

0168-1923

eISSN :

1873-2240

Publisher :

Elsevier Science, Amsterdam, Netherlands

Volume :

247

Issue :

2017

Pages :

131-138

Peer reviewed :

Peer Reviewed verified by ORBi

Available on ORBi :

since 08 August 2017

Statistics

Number of views

117 (21 by ULiège)

Number of downloads

3 (2 by ULiège)

More statistics

Scopus citations^®

Scopus citations^®
without self-citations

OpenCitations

OpenAlex citations

Bibliography

Andreas, E.L., et al. Statistics of surface-layer turbulence over terrain with metre-scale heterogeneity. Boundary Layer Meteorol. 86:3 (1998), 379–408.
Aubinet, M., et al. Estimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology. Adv. Ecol. Res. 30(C (1999), 113–175.
Aubinet, M., et al. Long term carbon dioxide exchange above a mixed forest in the Belgian Ardennes. Agric. For. Meteorol. 108 (2001), 293–315.
Aubinet, M., Heinesch, B., Longdoz, B., Estimation of the carbon sequestration by a heterogeneous forest: night flux corrections, heterogeneity of the site and inter-annual variability. Global Change Biol. 8:11 (2002), 1053–1071.
Aubinet, M., et al. Discriminating net ecosystem exchange between different vegetation plots in a heterogeneous forest. Agric. For. Meteorol. 132:3–4 (2005), 315–328.
Baldocchi, D.D., Assessing the eddy covariance technique for evaluating carbon dioxide exchange rates of ecosystems: past, present and future. Global Change Biol. 94 (2003), 479–492 (Available at: http://doi.wiley.com/10.1046/j.1365-2486.2003.00629.x. Accessed 06 September 2016).
Brunet, Y., Finnigan, J.J., Raupach, M.R., A wind tunnel study of air flow in waving wheat: single-point velocity statistics. Boundary Layer Meteorol. 70:1–2 (1994), 95–132.
Cava, D., Katul, G.G., On the scaling laws of the velocity-scalar cospectra in the canopy sublayer above tall forests. Boundary Layer Meteorol. 145:2 (2012), 351–367, 10.1007/s10546-012-9737-2.
Cava, D., et al. On the anomalous behaviour of scalar flux-variance similarity functions within the canopy sub-layer of a dense alpine forest. Boundary Layer Meteorol. 128:1 (2008), 33–57.
Finnigan, J., Turbulence in plant canopies. Annu. Rev. Fluid Mech. 32 (2000), 519–571.
Garratt, J.R., The Atmospheric Boundary Layer. 1994, Cambridge University Press, Cambridge.
Graf, A., et al. Intercomparison of methods for the simultaneous estimation of zero-plane displacement and aerodynamic roughness length from single-level eddy-covariance data. Boundary Layer Meteorol. 151:2 (2014), 373–387.
Guo, X., et al. Flux-variance method for latent heat and carbon dioxide fluxes in unstable conditions. Boundary Layer Meteorol. 131:3 (2009), 363–384.
Högström, U., Analysis of turbulence structure in the surface layer with a modified similarity formulation for near neutral conditions. J. Atmos. Sci. 47:16 (1990), 1949–1972.
Hong, J., et al. Response of ecosystem carbon and water vapour: exchanges in evolving nocturnal low-level jets. Asian J. Atmos. Environ. 6:3 (2012), 222–233.
Huang, J., Katul, G., Albertson, J., The role of coherent turbulent structures in explaining scalar dissimilarity within the canopy sublayer. Environ. Fluid Mech. 13:6 (2013), 571–599.
Irving, W., Nakane, H., Villarin, J.R.T., CHAPTER 5: time series consistency. IPCC Guidelines for National Greenhouse Gas Invetories, 2006 5.1–5.16.
Kaimal, J., Finnigan, J., Atmospheric Boundary Layer Flows: their Structure and Measurements. 1994, Oxford University Press.
Kaimal, J., et al. Spectral characteristics of surface-layer turbulence. Q. J. R. Meteorolog. Soc. 98 (1972), 563–589.
Katul, G., et al. Estimation of surface heat and momentum fluxes using the flux-variance method above uniform and non-uniform terrain. Boundary Layer Meteorol. 74:3 (1995), 237–260.
Katul, G., et al. Turbulent eddy motion at the forest atmosphere interface. J. Geophys. Res. 102:12 (1997), 409–421.
Kobayashi, N., Hiyama, T., Stability dependence of canopy flows over a flat larch forest. Boundary Layer Meteorol. 139:1 (2011), 97–120.
Kolle, O., Rebmann, C., EDDYSOFT by Meteotools – Documention of Eddy Covariance Software. 2009, Max-Planck-Institut fur Biogeochemie, Jena.
Laitat, É., et al. Contribution of forests and forestry to mitigate greenhouse effects Introduction: towards an integrated scientific approach for carbon accounting in forestry. Recherche, 2000, 241–251.
Li, D., Bou-Zeid, E., Coherent structures and the dissimilarity of turbulent transport of momentum and scalars in the unstable atmospheric surface layer. Boundary Layer Meteorol. 140:2 (2011), 243–262.
Mammarella, I., Dellwik, E., Jensen, N.O., Turbulence spectra, shear stress and turbulent kinetic energy budgets above two beech forest sites in Denmark. Tellus B 60 (2008), 179–187, 10.1111/j.1600-0889.2007.00326.x.
Maurer, K.D., et al. Canopy-structure effects on surface roughness parameters: observations in a Great Lakes mixed-deciduous forest. Agric. For. Meteorol. 177 (2013), 24–34, 10.1016/j.agrformet.2013.04.002.
Maurer, K.D., et al. Large-eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics. Biogeosciences 12:8 (2015), 2533–2548 Available at: http://www.biogeosciences.net/12/2533/2015/.
Moraes, O.L.L., et al. Comparing spectra and cospectra of turbulence over different surface boundary conditions. Phys. A: Stat. Mech. Applic. 387:19–20 (2008), 4927–4939.
Morin, T.H., et al. Environmental drivers of methane fluxes from an urban temperate wetland park. J. Geophys. Res. G: Biogeosci. 119:11 (2014), 2188–2208.
Moriwaki, R., Kanda, M., Local and global similarity in turbulent transfer of heat, water vapour, and CO2 in the dynamic convective sublayer over a suburban area. Boundary Layer Meteorol. 120:1 (2006), 163–179.
Munger, J.W., Loescher, H.W., Luo, H., Measurement, tower, and site design considerations. Aubinet, M., Vesala, T., Papale, D., (eds.) Eddy Covariance: a Practical Guide to Measurement and Data Analysis, 2012, Springer Netherlands, Dordrecht, 21–58, 10.1007/978-94-007-2351-1_2.
Nagy, M.T., et al. Footprint-adjusted net ecosystem CO2 exchange and carbon balance components of a temperate forest. Agric. For. Meteorol. 139:3–4 (2006), 344–360.
Ohtaki, E., Turbulent transport of CO2 over a paddy. Boundary Layer Meteorol. 19 (1980), 315–336.
Ohtaki, E., On the similarity in atmospheric fluctuations of carbon dioxide, water vapour and temperature over vegetated fields. Boundary-Layer Meteorol. 32:1 (1985), 25–37, 10.1007/BF00120712.
Perin, J., et al. Nouvelles courbves de productivités harmonisées pour le Douglas, l’épicéa et les mélèzes en Wallonie. Forêt Wallonne 129 (2014), 26–41.
Raupach, M.R., Coppin, P. a., Legg, B.J., Experiments on scalar dispersion within a model plant canopy, Part I: The turbulence structure. Boundary-Layer Meteorol. 35 (1986), 21–52 Available at: http://link.springer.com/10.1007/BF00117300.
Raupach, M.R., Finnigan, J.J., Brunei, Y., Coherent eddies and turbulence in vegetation canopies: the mixing-layer analogy. Boundary Layer Meteorol. 78:3–4 (1996), 351–382.
Rebmann, C., et al. Quality analysis applied on eddy covariance measurements at complex forest sites using footprint modelling. Theor. Appl. Climatol. 80:2–4 (2005), 121–141.
Ross, A.N., Vosper, S.B., Neutral turbulent flow over forested hills. Q. J. R. Meteorolog. Soc. 131:609 (2005), 1841–18621 Available at: http://doi.wiley.com/10.1256/qj.04.129.
Roth, M., Oke, T.R., Turbulent transfer relationships over an urban surface. 1. Spectral characteristics. Q. J. R. Meteorolog. Soc. 119:513 (1993), 1071–1104.
Roth, M., Oke, T.R., Relative efficiencies of turbulent transfer of heat, mass, and momentum over a patchy urban surface. J. Atmos. Sci. 52:11 (1995), 1863–1874.
Sakai, R.K., Fitzjarrald, D.R., Moore, K.E., Importance of low-frequency contributions to eddy fluxes observed over rough surfaces. J. Appl. Meteorol. 40:12 (2001), 2178–2192.
Shaw, R.H., Pereira, A.R., Aerodynamic roughness of a plant canopy: a numerical experiment. Agric. Meteorol. 26:1 (1982), 51–65.
Sogachev, A., et al. Effect of clearcuts on footprints and flux measurements above a forest canopy. Agric. For. Meteorol. 133:1–4 (2005), 182–196.
Stull, R.B., An Introduction to Boundary Layer Meteorology. Stull, R.B., (eds.), 1988, Kluwer Academic Publishers.
Su, H.B., et al. Spectral characteristics and correction of long-term eddy-covariance measurements over two mixed hardwood forests in non-flat terrain. Boundary Layer Meteorol. 110:2 (2004), 213–253.
Tian, X., et al. Estimating zero-plane displacement height and aerodynamic roughness length using synthesis of LiDAR and SPOT-5 data. Remote Sens. Environ. 115:9 (2011), 2330–2341.
Tian, F., et al. Remote sensing of environment evaluating temporal consistency of long-term global NDVI datasets for trend analysis. Remote Sens. Environ. 163 (2015), 326–340, 10.1016/j.rse.2015.03.031.
Turnipseed, A.A., et al. Airflows and turbulent flux measurements in mountainous terrain Part 1: canopy and local effects. Agric. Forest Meteorol. 119:1–2 (2003), 1–21.
Vesala, T., et al. Effect of thinning on surface fluxes in a boreal forest. Global Biogeochem. Cycles 19:2 (2005), 1–11.
Wilkinson, M., et al. Effects of management thinning on CO2 exchange by a plantation oak woodland in south-eastern England. Biogeosciences 13:8 (2016), 2367–2378.
Zitouna-Chebbi, R., et al. Accounting for vegetation height and wind direction to correct eddy covariance measurements of energy fluxes over hilly crop fields. J. Geophys. Res. Atmos. 120:10 (2015), 4920–4936.