Boundary-Layer Meteorology

, Volume 137, Issue 3, pp 493–507 | Cite as

Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

Open Access
Article

Abstract

Saturation of large aperture scintillometer (LAS) signals can result in sensible heat flux measurements that are biased low. A field study with LASs of different aperture sizes and path lengths was performed to investigate the onset of, and corrections for, signal saturation. Saturation already occurs at \({C_n^2 \approx 0.074 D^{5/3} \lambda^{1/3} L^{-8/3}}\), where \({C_n^2}\) is the structure parameter of the refractive index, D is the aperture size, λ is the wavelength, L is the transect length, which is smaller than theoretically derived saturation limits. At a transect length of 1 km, a height of 2.5 m, and aperture ≈0.15 m the correction factor exceeds 5% already at \({C_n^2=2\times 10^{-12}{\rm m}^{-2/3}}\), which will affect many practical applications of scintillometry. The Clifford correction method, which only depends on \({C_n^2}\) and the transect geometry, provides good saturation corrections over the range of conditions observed in our study. The saturation correction proposed by Ochs and Hill results in correction factors that are too small in large saturation regimes. An inner length scale dependence of the saturation correction factor was not observed. Thus for practical applications the Clifford correction method should be applied.

Keywords

Large aperture scintillometer Sensible heat flux Signal saturation Wave propagation 

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Copyright information

© The Author(s) 2010

Authors and Affiliations

  1. 1.Department of Mechanical and Aerospace EngineeringUniversity of CaliforniaSan DiegoUSA
  2. 2.Department of Meteorology and Air QualityWageningen UniversityWageningenThe Netherlands
  3. 3.Department of Earth and Environmental SciencesNew Mexico Institute of Mining and TechnologySocorroUSA

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