Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

• Published in: Boundary-layer meteorology Vol. 137; no. 3; pp. 493 - 507
• Main Authors: Kleissl, J, Hartogensis, O. K, Gomez, J. D
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-12-2010; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: algorithms; Analysis; Apertures; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; atmospheric surface-layer; Boundaries; calibration; Convection, turbulence, diffusion. Boundary layer structure and dynamics; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Flux; fluxes; inner-scale; Large aperture scintillometer; Meteorology; Methods; optical scintillation; Refractive index; Refractivity; Remote sensing; Saturation; Scintillation counters; Sensible heat flux; Signal saturation; sonic anemometer; strong turbulence; temperature; Wave propagation; Wavelengths; Signal saturation; Large aperture scintillometer; Wave propagation; Sensible heat flux; sensible heat; saturation; corrections; Height; refractive index; Scintillation counter; heat transfer
• DOI: 10.1007/s10546-010-9540-x
• EISSN: 1573-1472
• ISSN: 0006-8314

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 [graphic removed] , where [graphic removed] 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 [graphic removed] , which will affect many practical applications of scintillometry. The Clifford correction method, which only depends on [graphic removed] 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.