Boundary-Layer Meteorology

, 141:143 | Cite as

Effects of Non-Uniform Crosswind Fields on Scintillometry Measurements

  • H. C. WardEmail author
  • J. G. Evans
  • C. S. B. Grimmond


The effects of a non-uniform wind field along the path of a scintillometer are investigated. Theoretical spectra are calculated for a range of scenarios where the crosswind varies in space or time and compared to the ‘ideal’ spectrum based on a constant uniform crosswind. It is verified that the refractive-index structure parameter relation with the scintillometer signal remains valid and invariant for both spatially and temporally-varying crosswinds. However, the spectral shape may change significantly preventing accurate estimation of the crosswind speed from the peak of the frequency spectrum and retrieval of the structure parameter from the plateau of the power spectrum. On comparison with experimental data, non-uniform crosswind conditions could be responsible for previously unexplained features sometimes seen in observed spectra. By accounting for the distribution of crosswind, theoretical spectra can be generated that closely replicate the observations, leading to a better understanding of the measurements. Spatial variability of wind speeds should be expected for paths other than those that are parallel to the surface and over flat, homogenous areas, whilst fluctuations in time are important for all sites.


Crosswinds Scintillometry Sensible heat flux Spectra Structure parameter 


  1. Cheinet S, Beljaars A, Weiss-Wrana K, Hurtaud Y (2011) The use of weather forecasts to characterise near-surface optical turbulence. Boundary-Layer Meteorol 138(3): 453–473CrossRefGoogle Scholar
  2. Clifford SF (1971) Temporal-frequency spectra for a spherical wave propagating through atmospheric turbulence. J Opt Soc Am 61(10): 1285–1292CrossRefGoogle Scholar
  3. De Bruin HAR, Kohsiek W, Vandenhurk B (1993) A verification of some methods to determine the fluxes of momentum, sensible heat, and water-vapour using standard-deviation and structure parameter of scalar meteorological quantities. Boundary-Layer Meteorol 63(3): 231–257CrossRefGoogle Scholar
  4. Evans JG (2009) Long-path scintillometry over complex terrain to determine areal-averaged sensible and latent heat fluxes. PhD Thesis, The University of Reading, 181 ppGoogle Scholar
  5. Frehlich R (1992) Laser scintillation measurements of the temperature spectrum in the atmospheric surface-layer. J Atmos Sci 49(16): 1494–1509CrossRefGoogle Scholar
  6. Grimmond CSB, Oke TR (1999) Aerodynamic properties of urban areas derived, from analysis of surface form. J Appl Meteorol 38(9): 1262–1292CrossRefGoogle Scholar
  7. Hartogensis OK (2006) Exploring scintillometry in the stable atmospheric surface layer. PhD Thesis, Wageningen University, 240 ppGoogle Scholar
  8. Hartogensis OK, Watts CJ, Rodriguez JC, De Bruin HAR (2003) Derivation of an effective height for scintillometers: La Poza experiment in Northwest Mexico. J Hydrometeorol 4(5): 915–928CrossRefGoogle Scholar
  9. Hill RJ, Ochs GR (1978) Fine calibration of large-aperture optical scintillometers and an optical estimate of inner scale of turbulence. Appl Optics 17(22): 3608–3612CrossRefGoogle Scholar
  10. Hill RJ, Clifford SF, Lataitis RJ, Sarma AD (1990) Scintillation of millimeter-wave intensity and phase caused by turbulence and precipitation. Atmospheric propagation in the UV, visible, IR and MM-wave region and related systems aspects (AGARD-CP-454), 9–13 October 1990, Copenhagen, DenmarkGoogle Scholar
  11. Hill RJ, Ochs GR, Wilson JJ (1992) Measuring surface-layer fluxes of heat and momentum using optical scintillation. Boundary-Layer Meteorol 58(4): 391–408CrossRefGoogle Scholar
  12. Irvine M, Lagouarde JP, Bonnefond JM, Grimmond CSB, Oke T (2002) Spectral analyzes of optical scintillation: refraction and absorption components in an urban zone. In: Preprint Fourth symposium on the Urban environment. AMS, Norfolk, Virginia, USAGoogle Scholar
  13. Kanda M, Moriwaki R, Roth M, Oke T (2002) Area-averaged sensible heat flux and a new method to determine zero-plane displacement length over an urban surface using scintillometry. Boundary-Layer Meteorol 105(1): 177–193CrossRefGoogle Scholar
  14. Kipp and Zonen (2005) Large aperture scintillometer instruction manual. Delft, The Netherlands, 70 ppGoogle Scholar
  15. Kohsiek W (1982) Measuring Ct2, Cq2, and Ctq in the unstable surface-layer, and relations to the vertical fluxes of heat and moisture. Boundary-Layer Meteorol 24(1): 89–107CrossRefGoogle Scholar
  16. Lagouarde JP, Irvine M, Bonnefond JM, Grimmond CSB, Long N, Oke TR, Salmond JA, Offerle B (2006) Monitoring the sensible heat flux over urban areas using large aperture scintillometry: case study of Marseille city during the Escompte experiment. Boundary-Layer Meteorol 118(3): 449–476CrossRefGoogle Scholar
  17. Lawrence RS, Ochs GR, Clifford SF (1972) Use of scintillations to measure average wind across a light-beam. Appl Optics 11(2): 239–243CrossRefGoogle Scholar
  18. Medeiros Filho F, Jayasuriya D, Cole R, Helmis C (1983) Spectral density of millimeter wave amplitude scintillations in an absorption region. IEEE Trans Antennas Propag 31(4): 672–676CrossRefGoogle Scholar
  19. Meijninger WML (2003) Surface fluxes over natural landscapes using scintillometry. PhD, Wageningen University, 170 ppGoogle Scholar
  20. Meijninger WML, Green AE, Hartogensis OK, Kohsiek W, Hoedjes JCB, Zuurbier RM, De Bruin HAR (2002) Determination of area-averaged water vapour fluxes with large aperture and radio wave scintillometers over a heterogeneous surface—Flevoland field experiment. Boundary-Layer Meteorol 105(1): 63–83CrossRefGoogle Scholar
  21. Meijninger WML, Beyrich F, Lüdi A, Kohsiek W, De Bruin HAR (2006) Scintillometer-based turbulent fluxes of sensible and latent heat over a heterogeneous land surface—a contribution to Litfass-2003. Boundary-Layer Meteorol 121(1): 89–110CrossRefGoogle Scholar
  22. Monin AS, Yaglom AM (1971) Statistical fluid mechanics: mechanics of turbulence. MIT, Cambridge, 782 ppGoogle Scholar
  23. Nieveen JP, Green AE, Kohsiek W (1998) Using a large-aperture scintillometer to measure absorption and refractive index fluctuations. Boundary-Layer Meteorol 87(1): 101–116CrossRefGoogle Scholar
  24. Otto WD, Hill RJ, Sarma AD, Wilson JJ, Andreas EL, Gosz JR, Moore DI (1996) Results of the millimeter-wave instrument operated at Sevilleta, New Mexico. Natl Oceanic Atmos Admin, pp 47Google Scholar
  25. Poggio LP, Furger M, Prevot ASH, Graber WK, Andreas EL (2000) Scintillometer wind measurements over complex terrain. J Atmos Ocean Technol 17(1): 17–26CrossRefGoogle Scholar
  26. Potvin G, Dion D, Forand JL (2005) Wind effects on scintillation decorrelation times. Opt Eng 44(1): 1–12CrossRefGoogle Scholar
  27. Rao RZ, Wang SP, Liu XC, Gong ZB (1999) Turbulence spectrum effect on wave temporal-frequency spectra for light propagating through the atmosphere. J Opt Soc Am A Opt Image Sci Vis 16(11): 2755–2762CrossRefGoogle Scholar
  28. Roth M, Salmond JA, Satyanarayana ANV (2006) Methodological considerations regarding the measurement of turbulent fluxes in the urban roughness sublayer: the role of scintillometry. Boundary-Layer Meteorol 121(2): 351–375CrossRefGoogle Scholar
  29. Stull RB (1988) An introduction to boundary layer meteorology. Kluwer, Dordrecht, 666 ppGoogle Scholar
  30. Tatarski VI (1961) Wave propagation in a turbulent medium. McGraw-Hill, New York, 285 ppGoogle Scholar
  31. Van Kesteren AJH (2008) Sensible and latent heat fluxes with optical and millimetre wave scintillometers: a theory review and the Chilbolton experiment. Masters, Wageningen University, 99 ppGoogle Scholar
  32. Von Randow C, Kruijt B, Holtslag AAM, de Oliveira MBL (2008) Exploring eddy-covariance and large-aperture scintillometer measurements in an Amazonian rain forest. Agric For Meteorol 148(4): 680–690CrossRefGoogle Scholar
  33. Wang TI, Ochs GR, Clifford SF (1978) A saturation-resistant optical scintillometer to measure C2n. J Opt Soc Am 68(3): 334–338CrossRefGoogle Scholar
  34. Wang TI, Ochs GR, Lawrence RS (1981) Wind measurements by the temporal cross-correlation of the optical scintillations. Appl Opt 20(23): 4073–4081CrossRefGoogle Scholar
  35. Wheelon AD (2006) Electromagnetic scintillation: weak scattering. Cambridge University Press, UK, 446 ppGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • H. C. Ward
    • 1
    • 2
    Email author
  • J. G. Evans
    • 1
  • C. S. B. Grimmond
    • 2
  1. 1.Centre for Ecology and HydrologyWallingfordUK
  2. 2.Environmental Monitoring and Modelling Group, Department of GeographyKing’s College LondonLondonUK

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