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Turbulence characteristics and dispersion in a forest - tests of Thomson's random-flight model

Författare:
Publiceringsår: 2004
Språk: Engelska
Sidor: 203-222
Publikation/Tidskrift/Serie: Flux and Concentration Footprints (Agricultural and Forest Meteorology)
Volym: 127
Nummer: 3-4
Dokumenttyp: Konferensbidrag
Förlag: Elsevier Science B.V.

Sammanfattning

A dispersion experiment, where the tracer SF6 Was released from line sources, was carried out within a young pine forest. Line sources made of silicone tubes were installed at different heights and distances from a tower. Vertical concentration profiles were measured on the tower and the samples were analysed with a gas chromatograph. The measured concentration profiles were compared to those calculated using Thomson's random-flight model. To provide input information to the model on turbulence, the turbulence characteristics were measured at four different heights with sonic anemometers. Data are presented for standard deviations of the velocity components, the momentum flux, the Lagrangian time scale and the mean horizontal wind velocity, depending on height and thermal stability. The derived turbulence characteristics resemble previous results in the literature; but are still stand specific. Satisfactory agreement was obtained between the measured and simulated SF6 concentration profiles. However, the model clearly underestimates the concentrations in the upper part of the stand. The results should add more confidence to the continued use of Thomson's model and are useful for planning better dispersion experiments. (C) 2004 Elsevier B.V. All rights reserved.

Disputation

Nyckelord

  • Earth and Environmental Sciences
  • line source
  • footprint
  • velocity standard deviation
  • pine forest
  • Lagrangian time scale
  • experiment
  • tracer

Övriga

Flux and Concentration Footprints
26-28 May 2003
Juupajoki, Finland
Published
Yes
  • ISSN: 0168-1923

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