• Anfossi, D., G. Degrazia, E. Ferrero, S. E. Gryning, M. G. Morselli, and S. T. Castelli, 2000: Estimation of the Lagrangian structure function constant C0 from surface-layer wind data. Bound.-Layer Meteor., 95 , 249270.

    • Search Google Scholar
    • Export Citation
  • Baldocchi, D., 1997: Flux footprints within and over forest canopies. Bound.-Layer Meteor., 85 , 273292.

  • Baldocchi, D., 2003: Assessing the eddy-covariance technique for evaluating carbon dioxide exchange rates of ecosystems: Past, present and future. Global Change Biol., 9 , 479493.

    • Search Google Scholar
    • Export Citation
  • Baldocchi, D., and T. P. Meyers, 1989: The effects of extreme turbulent events on the estimation of aerodynamic variables in a deciduous forest canopy. Agric. For. Meteor., 48 , 117134.

    • Search Google Scholar
    • Export Citation
  • Brunet, Y., and M. Irvine, 2000: The control of coherent eddies in vegetation canopies: Streamwise structure spacing, canopy shear scale and atmospheric stability. Bound.-Layer Meteor., 94 , 139163.

    • Search Google Scholar
    • Export Citation
  • Brunet, Y., J. J. Finnigan, and M. R. Raupach, 1994: A wind tunnel study of airflow in waving wheat: Single-point velocity statistics. Bound.-Layer Meteor., 70 , 95132.

    • Search Google Scholar
    • Export Citation
  • Cai, X., and M. Y. Leclerc, 2007: Forward-in-time and backward-in-time dispersion in the convective boundary layer and their equivalence on concentration footprint. Bound.-Layer Meteor., 123 , 201218.

    • Search Google Scholar
    • Export Citation
  • Cai, X., G. Peng, X. Guo, and M. Y. Leclerc, 2008: Evaluation of backward and forward Lagrangian footprint models in the surface layer. Theor. Appl. Climatol., doi:10.1007/s00704-007-0334-0, in press.

    • Search Google Scholar
    • Export Citation
  • Cionco, R. M., 1965: A mathematical model for air flow in a vegetative cover. J. Appl. Meteor., 4 , 517522.

  • Coppin, P. A., M. R. Raupach, and B. J. Legg, 1986: Experiments on scalar dispersion within a model plant canopy. Part II: An elevated plane source. Bound.-Layer Meteor., 35 , 167191.

    • Search Google Scholar
    • Export Citation
  • Finn, D., B. Lamb, M. Y. Leclerc, and T. W. Horst, 1996: Experimental evaluation of analytical and Lagrangian surface-layer flux footprint models. Bound.-Layer Meteor., 80 , 283308.

    • Search Google Scholar
    • Export Citation
  • Finnigan, J. J., 1979: Turbulence in waving wheat. I: Mean statistics and honami. Bound.-Layer Meteor., 16 , 181211.

  • Fitzmaurice, L., R. H. Shaw, K. T. Paw U, and E. G. Patton, 2004: Three-dimensional scalar microfront systems in a large-eddy simulation of vegetation canopy flow. Bound.-Layer Meteor., 112 , 107127.

    • Search Google Scholar
    • Export Citation
  • Flesch, T., and J. D. Wilson, 1992: A two-dimensional trajectory-simulation model for non-Gaussian, inhomogeneous turbulence within plant canopies. Bound.-Layer Meteor., 61 , 349374.

    • Search Google Scholar
    • Export Citation
  • Foken, T., and M. Y. Leclerc, 2004: A survey of methods used to validate footprint models and their limitations. Agric. For. Meteor., 127 , 223234.

    • Search Google Scholar
    • Export Citation
  • Gao, W., R. H. Shaw, and K. T. Paw U, 1989: Observation of organized structure in turbulent flow within and above a forest canopy. Bound.-Layer Meteor., 47 , 349377.

    • Search Google Scholar
    • Export Citation
  • Hollinger, D. Y., and Coauthors, 2004: Spatial and temporal variability in forest–atmosphere CO2 exchange. Global Change Biol., 10 , 16891706.

    • Search Google Scholar
    • Export Citation
  • Holtslag, A. A. M., and C-H. Moeng, 1991: Eddy diffusivity and countergradient transport in the convective boundary layer. J. Atmos. Sci., 48 , 16901698.

    • Search Google Scholar
    • Export Citation
  • Horst, T. W., and J. C. Weil, 1992: Footprint estimation for scalar flux measurements in the atmospheric surface layer. Bound.-Layer Meteor., 59 , 279296.

    • Search Google Scholar
    • Export Citation
  • Horst, T. W., and J. C. Weil, 1994: How far is far enough? The fetch requirements for micrometeorological measurement of surface fluxes. J. Atmos. Oceanic Technol., 11 , 10181025.

    • Search Google Scholar
    • Export Citation
  • Kanda, M., and M. Hino, 1994: Organized structures in developing turbulent flow within and above a plant canopy, using a large eddy simulation. Bound.-Layer Meteor., 68 , 237257.

    • Search Google Scholar
    • Export Citation
  • Katul, G. G., D. Poggi, D. Cava, and J. J. Finnigan, 2006: The relative importance of ejections and sweeps to momentum transfer in the atmospheric boundary layer. Bound.-Layer Meteor., 120 , 367375.

    • Search Google Scholar
    • Export Citation
  • Kljun, N., M. W. Rotach, and H. P. Schmid, 2002: A 3D backward Lagrangian footprint model for a wide range of boundary layer stratifications. Bound.-Layer Meteor., 103 , 205226.

    • Search Google Scholar
    • Export Citation
  • Kurbanmuradov, O., and K. K. Sabelfeld, 2000: Lagrangian stochastic models for turbulent dispersion in the atmospheric boundary layer. Bound.-Layer Meteor., 97 , 191218.

    • Search Google Scholar
    • Export Citation
  • Kurbanmuradov, O., Ü Rannik, K. K. Sabelfeld, and T. Vesala, 2001: Evaluation of mean concentration and fluxes in turbulent flows by stochastic Lagrangian models. Math. Comp. Simul., 54 , 459476.

    • Search Google Scholar
    • Export Citation
  • Leclerc, M. Y., and G. W. Thurtell, 1990: Footprint prediction of scalar fluxes using a Markovian analysis. Bound.-Layer Meteor., 52 , 247258.

    • Search Google Scholar
    • Export Citation
  • Leclerc, M. Y., S. Shen, and B. Lamb, 1997: Observations and large-eddy simulation modeling of footprints in the lower convective boundary layer. J. Geophys. Res., 102 , 93239334.

    • Search Google Scholar
    • Export Citation
  • Leclerc, M. Y., A. Karipot, T. Prabha, G. Allwine, B. Lamb, and H. L. Gholz, 2003a: Impact of non-local advection on flux footprints over a tall forest canopy: A tracer flux experiment. Agric. For. Meteor., 115 , 1734.

    • Search Google Scholar
    • Export Citation
  • Leclerc, M. Y., N. Meskhidze, and D. Finn, 2003b: Comparison between a tracer flux experiment and model footprint predictions over a homogeneous canopy of intermediate roughness. Agric. For. Meteor., 117 , 145158.

    • Search Google Scholar
    • Export Citation
  • Lee, X., 2003: Fetch and footprint of turbulent fluxes over vegetative stands with elevated sources. Bound.-Layer Meteor., 107 , 561579.

    • Search Google Scholar
    • Export Citation
  • Lee, X., 2004: A model for scalar advection inside canopies and application to footprint investigation. Agric. For. Meteor., 127 , 131141.

    • Search Google Scholar
    • Export Citation
  • Legg, B. J., M. R. Raupach, and P. A. Coppin, 1986: Experiments on scalar dispersion within a model canopy. Part III: An elevated line source. Bound.-Layer Meteor., 35 , 277302.

    • Search Google Scholar
    • Export Citation
  • Leuning, R., 2000: Estimation of scalar source/sink distributions in plant canopies using Lagrangian dispersion analysis: Corrections for atmospheric stability and comparison with a multilayer canopy model. Bound.-Layer Meteor., 96 , 293314.

    • Search Google Scholar
    • Export Citation
  • Luhar, A. K., and R. E. Britter, 1989: A random walk model for dispersion in inhomogeneous turbulence in a convective boundary layer. Atmos. Environ., 23 , 19111924.

    • Search Google Scholar
    • Export Citation
  • Markkanen, T., Ü Rannik, B. Marcolla, A. Cescatti, and T. Vesala, 2003: Footprints and fetches for fluxes over forest canopies with varying structure and density. Bound.-Layer Meteor., 106 , 437459.

    • Search Google Scholar
    • Export Citation
  • Mölder, M., L. Klemedtsson, and A. Lindroth, 2004: Turbulence characteristics and dispersion in a forest—Tests of Thomson’s random-flight model. Agric. For. Meteor., 127 , 203222.

    • Search Google Scholar
    • Export Citation
  • Patton, E. G., R. H. Shaw, M. J. Judd, and M. R. Raupach, 1998: Large-eddy simulation of windbreak flow. Bound.-Layer Meteor., 87 , 275306.

    • Search Google Scholar
    • Export Citation
  • Patton, E. G., K. J. Davis, M. C. Barth, and P. P. Sullivan, 2001: Decaying scalars emitted by a forest canopy: A numerical study. Bound.-Layer Meteor., 100 , 91129.

    • Search Google Scholar
    • Export Citation
  • Poggi, D., A. Porporato, L. Ridolfi, J. D. Albertson, and G. G. Katul, 2004: The effect of vegetation density on canopy sub-layer turbulence. Bound.-Layer Meteor., 111 , 565587.

    • Search Google Scholar
    • Export Citation
  • Poggi, D., G. Katul, and J. Albertson, 2006: Scalar dispersion within a model canopy: Measurements and three-dimensional Lagrangian models. Adv. Water Resour., 29 , 326335.

    • Search Google Scholar
    • Export Citation
  • Qiu, G., and J. S. Warland, 2006: Inferring profiles of energy fluxes within a soybean canopy using Lagrangian analysis. Agric. For. Meteor., 139 , 119137.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, M. Aubinet, O. Kurbanmuradov, K. K. Sabelfeld, T. Markkanen, and T. Vesala, 2000: Footprint analysis for measurements over a heterogeneous forest. Bound.-Layer Meteor., 97 , 137166.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, and Coauthors, 2002a: Fluxes of carbon dioxide and water vapour over Scots pine forest and clearing. Agric. For. Meteor., 111 , 187202.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, M. Aubinet, O. Kurbanmuradov, K. K. Sabelfeld, T. Markkanen, and T. Vesala, 2002b: Footprint analysis for measurements over a heterogeneous forest. Bound.-Layer Meteor., 97 , 137166.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, T. Markkanen, J. Raittila, P. Hari, and T. Vesala, 2003: Turbulence statistics inside and over forest: Influence on footprint prediction. Bound.-Layer Meteor., 109 , 163189.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, P. Keronena, P. Harib, and T. Vesala, 2004: Estimation of forest–atmosphere CO2 exchange by eddy covariance and profile techniques. Agric. For. Meteor., 126 , 141155.

    • Search Google Scholar
    • Export Citation
  • Raupach, M. R., P. A. Coppin, and B. J. Legg, 1986: Experiments on scalar dispersion within a model plant canopy. Part 1: The turbulence structure. Bound.-Layer Meteor., 35 , 2152.

    • Search Google Scholar
    • Export Citation
  • Reynolds, A. M., 1998a: On the formulation of Lagrangian stochastic models of scalar dispersion within plant canopies. Bound.-Layer Meteor., 86 , 333344.

    • Search Google Scholar
    • Export Citation
  • Reynolds, A. M., 1998b: A Lagrangian stochastic model for the trajectories of particle pairs and its application to the prediction of concentration variance within plant canopies. Bound.-Layer Meteor., 88 , 467478.

    • Search Google Scholar
    • Export Citation
  • Shaw, R. H., and U. Schumann, 1992: Large-eddy simulation of turbulent flow above and within a forest. Bound.-Layer Meteor., 61 , 4764.

    • Search Google Scholar
    • Export Citation
  • Shaw, R. H., and E. G. Patton, 2003: Canopy element influences on resolved- and subgrid-scale energy within a large-eddy simulation. Agric. For. Meteor., 115 , 517.

    • Search Google Scholar
    • Export Citation
  • Shaw, R. H., J. Tavangar, and D. P. Ward, 1983: Structure of the Reynolds stress in a canopy layer. J. Climate Appl. Meteor., 22 , 19221931.

    • Search Google Scholar
    • Export Citation
  • Schmid, H. P., 1994: Source areas for scalars and scalar fluxes. Bound.-Layer Meteor., 67 , 293318.

  • Schmid, H. P., 2002: Footprint modelling for vegetation atmosphere exchange studies: A review and perspective. Agric. For. Meteor., 113 , 159183.

    • Search Google Scholar
    • Export Citation
  • Schmid, H. P., and T. R. Oke, 1990: A model to estimate the source area contributing to turbulent exchange in the surface layer over patchy terrain. Quart. J. Roy. Meteor. Soc., 116 , 965988.

    • Search Google Scholar
    • Export Citation
  • Schuepp, P. H., M. Y. Leclerc, J. I. Macpherson, and R. L. Desjardins, 1990: Footprint prediction of scalar fluxes from analytical solutions of the diffusion equation. Bound.-Layer Meteor., 50 , 353373.

    • Search Google Scholar
    • Export Citation
  • Shen, S., and M. Y. Leclerc, 1997: Modeling the turbulence structure in the canopy layer. Agric. For. Meteor., 87 , 325.

  • Strong, C., J. D. Fuentes, and D. Baldocchi, 2004: Reactive hydrocarbon flux footprints during canopy senescence. Agric. For. Meteor., 127 , 159173.

    • Search Google Scholar
    • Export Citation
  • Su, H. B., R. H. Shaw, K. T. Paw U, C-H. Moeng, and P. Sullivan, 1998: Turbulent statistics of neutrally stratified flow within and above a sparse forest from large-eddy simulation and field observations. Bound.-Layer Meteor., 88 , 363397.

    • Search Google Scholar
    • Export Citation
  • Thomson, D. J., 1987: Criteria for the selection of stochastic models of particle trajectories in turbulent flows. J. Fluid Mech., 180 , 529556.

    • Search Google Scholar
    • Export Citation
  • Warland, J., and G. E. Thurtell, 2000: A Lagrangian solution to the relationship between a distributed source and concentration profile. Bound.-Layer Meteor., 96 , 453471.

    • Search Google Scholar
    • Export Citation
  • Watanabe, T., 2004: Large-eddy simulation of coherent turbulence structures associated with scalar ramps over plant canopies. Bound.-Layer Meteor., 112 , 307341.

    • Search Google Scholar
    • Export Citation
  • Yi, C., R. K. Monson, Z. Zhai, D. E. Anderson, B. Lamb, G. Allwine, A. A. Turnipseed, and S. P. Burns, 2005: Modeling and measuring the nocturnal drainage flow in a high-elevation, subalpine forest with complex terrain. J. Geophys. Res., 110 .D22303, doi:10.1029/2005JD006282.

    • Search Google Scholar
    • Export Citation
  • Yue, W., C. Meneveau, M. B. Parlange, W. Zhu, R. van Hout, and J. Katz, 2007a: A comparative quadrant analysis of turbulence in a plant canopy. Water Resour. Res., 43 .W05422, doi:10.1029/2006WR005583.

    • Search Google Scholar
    • Export Citation
  • Yue, W., M. B. Parlange, C. Meneveau, W. Zhu, R. van Hout, and J. Katz, 2007b: Large-eddy simulation of plant canopy flows using plant-scale representation. Bound.-Layer Meteor., 124 , 183203.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 61 37 4
PDF Downloads 37 28 6

Comparison of In-Canopy Flux Footprints between Large-Eddy Simulation and the Lagrangian Simulation

View More View Less
  • 1 Laboratory for Environmental Physics, and Biological and Agricultural Engineering, The University of Georgia, Griffin, Georgia
  • | 2 Laboratory for Environmental Physics, The University of Georgia, Griffin, Georgia
  • | 3 University of California, Berkeley, Berkeley, California
Restricted access

Abstract

Flux footprints for neutral shear-driven canopy flows are evaluated using large-eddy simulation (LES) and a Lagrangian stochastic (LS) model. The Lagrangian stochastic model is driven by flow statistics derived from the large-eddy simulation. LES results suggest that both surface and elevated sources inside the canopy contribute equally to the cumulative flux from an upwind distance of 4 times the canopy height. LES flux footprints are more contracted than those obtained using the Lagrangian stochastic model. This is attributed to an enhanced vertical diffusion and reduced horizontal diffusion. The ejection and sweep contributions to momentum exchange in the Lagrangian stochastic model are weaker than those in the large-eddy simulation. Ejections of low-momentum air dominate at all levels in the canopy modeled by the LES. In contrast, high-momentum sweep events are dominant within the LES canopy and low-momentum ejection events are dominant above the canopy. Dispersion parameters for the first- and second-order statistics of concentration from both LES and LS for three line sources representing the canopy crown, midcanopy, and surface sources are also investigated. Lagrangian model results are sensitive to the choice of the time scale. A time scale based on the dissipation rate agrees well with the LS and LES plume heights of surface source. However, flux footprints from LS are closer to those from the LES, while an intermediate time scale (0.15z/σw) was used inside the canopy.

Corresponding author address: M. Y. Leclerc, Laboratory for Environmental Physics, The University of Georgia, 1109 Experiment St., Griffin, GA 30223. Email: mleclerc@uga.edu

Abstract

Flux footprints for neutral shear-driven canopy flows are evaluated using large-eddy simulation (LES) and a Lagrangian stochastic (LS) model. The Lagrangian stochastic model is driven by flow statistics derived from the large-eddy simulation. LES results suggest that both surface and elevated sources inside the canopy contribute equally to the cumulative flux from an upwind distance of 4 times the canopy height. LES flux footprints are more contracted than those obtained using the Lagrangian stochastic model. This is attributed to an enhanced vertical diffusion and reduced horizontal diffusion. The ejection and sweep contributions to momentum exchange in the Lagrangian stochastic model are weaker than those in the large-eddy simulation. Ejections of low-momentum air dominate at all levels in the canopy modeled by the LES. In contrast, high-momentum sweep events are dominant within the LES canopy and low-momentum ejection events are dominant above the canopy. Dispersion parameters for the first- and second-order statistics of concentration from both LES and LS for three line sources representing the canopy crown, midcanopy, and surface sources are also investigated. Lagrangian model results are sensitive to the choice of the time scale. A time scale based on the dissipation rate agrees well with the LS and LES plume heights of surface source. However, flux footprints from LS are closer to those from the LES, while an intermediate time scale (0.15z/σw) was used inside the canopy.

Corresponding author address: M. Y. Leclerc, Laboratory for Environmental Physics, The University of Georgia, 1109 Experiment St., Griffin, GA 30223. Email: mleclerc@uga.edu

Save