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Vanessa Haverd, Ray Leuning, David Griffith, Eva van Gorsel, Matthias Cuntz February 06, 2008

The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions. Vanessa Haverd, Ray Leuning, David Griffith, Eva van Gorsel, Matthias Cuntz February 06, 2008. z ref ; c ref. z m = h c. z j. S j.

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Vanessa Haverd, Ray Leuning, David Griffith, Eva van Gorsel, Matthias Cuntz February 06, 2008

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  1. The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions Vanessa Haverd, Ray Leuning, David Griffith, Eva van Gorsel, Matthias Cuntz February 06, 2008

  2. zref ; cref zm = hc zj Sj zi ; ci zj-1 z0 = 0 Lagrangian Dispersion in Plant Canopies Dispersion Matrix, D • Calculated using Lagrangian Dispersion theory (e.g. LNF, Raupach 1989) • Inputs are turbulence statistics • Standard deviation of vertical wind velocity: sw (measured) • Lagrangian Timescale: TL (parameterised) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  3. Lagrangian Dispersion in Plant Canopies: Applications CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  4. Parameterisations of Lagrangian Timescale, TL CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  5. SVAT model Turbulence stats (obs) Sj sw ci – cref (predicted) Turbulent transfer Model (LNF) Dij TL cost Prior TL ci - cref (obs) param opt Approach(1) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  6. Met data Fixed parameters Leaf angle distribution parameter, cL Stomatal conductance/ photosyn params, a1, Ds,0, Vc,max,0, a param opt SVAT model param opt Pgap (predicted) Net fluxes (predicted) cost Leaf area density distribution cost Pgap (obs) Net fluxes (obs) Source/sink distribution Sj Approach(2) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  7. SVAT model, applied to Tumbarumba • Multilayer canopy model (Wang and Leuning, 1998) • Sunlit/ shaded leaf model coupling stomatal conductance, photosynthesis and energy partitioning • Radiation distribution in the canopy (3 wave-bands) • Recent additions • Soil and biomass respiration rates (Keith et al. 2008) • Heat storage fluxes in the canopy air and biomass (Haverd et al. 2007) • Multilayer soil model with coupled heat/moisture fluxes and litter CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  8. Measurements 70 m tower in 40 m temperate Eucalyptus forest (Tumbarumba Ozflux site) • Continuous measurements at 70 m: • eddy fluxes (H, lE, CO2) • Rnet • upward and downward solar radiation fluxes • met data • Continuous temperature and water vapour profiles • 2 week campaign (Nov 2006) • 7 tower inlets to 2 Fourier transform infrared spectrometers • Hourly measurements of CO2, water vapour • Ground-based Lidar measurements of direct beam transmission probability (Pgap) and hence foliage density profile. (Jupp et al. 2008) • Array of 3D sonic anemometers sw profile, Eulerian timescale. • Chamber measurements of CO2 and CH4 soil fluxes (Fest et al. 2008) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  9. Measured Concentration Profiles CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  10. Foliage Area Volume Density and Pgap Jupp et al., 2008 CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  11. Hourly Net Fluxes at 70 m CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  12. Vertical source/sink distributions CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  13. Hourly flux partitioning between ground and vegetation CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  14. Turbulence Statistics from Measurements CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  15. (Styles et al. 2002) Functional form of TL c1→∞; c2 = 0.32c1 = 0; c2 = 0.32c1 = 7.32; c2 = 0.32 CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  16. Measured and Predicted Concentrations using prior TL (Styles et al. parameterisation) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  17. Measured and Predicted Concentrations using optimised TL (Styles et al. parameterisation) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  18. Massman and Weil parameterisation (1999) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  19. Measured and Predicted Concentrations using optimised TL (Styles et al. and MW parameterisations) CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  20. Prior and Optimised Profiles of TL Styles et al. Massman and Weil Piecewise linear CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  21. Summary • TL required to calculate dispersion matrix linking in-canopy source/sinks to concentrations. • High uncertainty in TL because it cannot be measured directly • We have estimated the profile of TL using • Hourly vertical profiles of θ, [CO2], [H2O] • SVAT model predictions of source/sink distributions and uncertainites, constrained by meaurements : • Net fluxes above canopy • Chamber measurements of CO2 ground fluxes • Pgap from ground-based Lidar • Result: with c1 = 8.4±3.2; c2 = 0.49±0.05 • decreases with canopy depth • 1.7 times higher than prior estimate based on TE CSIRO.The Lagrangian time scale for turbulent transport in forest canopies, determined from measured fluxes and concentrations and modelled source distributions

  22. Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au Thank you CMAR Vanessa Haverd Phone: 02 6246 5981 Email:vanessa.haverd@csiro.au

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