HR: 1340h
AN: B13B-1182    [Abstracts]
TI: Implications of in-canopy sources and concentration profiles for Lagrangian turbulence statistics.
AU: Haverd, V E
EM: vanessa.haverd@csiro.au
AF: CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601, Australia
AU: Haverd, V E
EM: vanessa.haverd@csiro.au
AF: Department of Chemistry, University of Wollongong, Northfileds Ave, Wollongong, NSW 2522, Australia
AU: * Leuning, R
EM: ray.leuning@csiro.au
AF: CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601, Australia
AU: Griffith, D W
EM: griffith@uow.edu.au
AF: CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601, Australia
AU: van Gorsel, E
EM: eva.vangorsel@csiro.au
AF: CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601, Australia
AU: Livesley, S
EM: sjlive@unimelb.edu.au
AF: School of Forest and Ecosystem Science, University of Melbourne, 500 Yarra Boulevard, Richmond, Melbourne, Vic 3121, Australia
AU: Fest, B
EM: benedikt.fest@mytum.de
AF: School of Forest and Ecosystem Science, University of Melbourne, 500 Yarra Boulevard, Richmond, Melbourne, Vic 3121, Australia
AB: One-dimensional Lagrangian dispersion models are often used to infer in-canopy source/sink distributions from concentration profiles. Such models require vertical profiles of the standard deviation of the vertical windspeed (σ_w) and the Lagrangian timescale (τ_L). While (σ_w) can be measured, (τ_L) cannot, and is usually either parameterised hypothetically or inferred from its Eulerian counterpart, and thus remains uncertain. In this work, we measure (σ_w) and infer (τ_L) from measured profiles of temperature and concentrations of H₂O, CO₂ and CH₄, measured simultaneously by Fourier transform infrared spectroscopy. The study site is a 40-m tall temperate Eucalyptus forest in south-eastern Australia. Source/sink distributions of these quantities are derived from a multilayer Soil Vegetation Atmospheric Transfer (SVAT) model with multiple constraints: (1) day-time eddy flux measurements above the canopy of sensible heat, latent heat, and CO₂ (2) in-canopy Lidar measurements of the leaf area density distribution, (3) chamber measurements of CH₄ and CO₂ ground fluxes. An a-priori estimate of (τ_L) is obtained from the Eulerian timescale. A Lagrangian dispersion model is inverted to obtain an improved estimate of (τ_L) which optimises agreement between modelled and measured vertical profiles of temperature and the scalar concentrations. The inferred vertical profile of ôL is compared to several theoretical profiles predicted in the literature.
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0452 Instruments and techniques
DE: 0466 Modeling
DE: 0490 Trace gases
DE: 3322 Land/atmosphere interactions (1218, 1631, 1843)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting