Path-averaged surface fluxes determined from infrared and microwave scintillometers

A. E. Green*, M. S. Astill, K. J. McAneney, J. P. Nieveen

*Corresponding author for this work

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Methods are needed to measure the surface fluxes of sensible (H) and latent heat (E) at large scales. A promising method is scintillometry. Over pasture, a near-infrared scintillometer was most sensitive to temperature fluctuations whilst a microwave scintillometer was unduly affected by both humidity fluctuations and correlated temperature-humidity fluctuations. Slower changes in path-averaged humidity caused additional signal variance and an overestimation of H and E. Log-amplitude spectra of the microwave scintillometer signal showed inertial-convective subrange behavior. In combination, path-averaged E and H could be determined over 3 km. Independent corroborative measurements of H and E were made at the path midpoint using the eddy covariance technique. For sensible heat, agreement was within 4% over a measured range 0-300 W m-2, with a residual standard deviation of 45 W m-2. Latent heat agreed at best to within 12% over the range 0-450 W m-2 (residual standard deviation of 94 W m-2) and an offset of 30 W m-2.

Original languageEnglish
Pages (from-to)233-247
Number of pages15
JournalAgricultural and Forest Meteorology
Volume109
Issue number3
DOIs
Publication statusPublished - 3 Sep 2001
Externally publishedYes

Keywords

  • Large scale
  • Latent heat flux
  • Path average
  • Scintillation
  • Sensible heat flux

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