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Sensors 2014, 14(2), 2150-2170; doi:10.3390/s140202150
Article

Assessing Inter-Sensor Variability and Sensible Heat Flux Derivation Accuracy for a Large Aperture Scintillometer

 and *
Received: 13 November 2013; in revised form: 25 December 2013 / Accepted: 16 January 2014 / Published: 27 January 2014
(This article belongs to the Section Remote Sensors)
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Abstract: The accuracy in determining sensible heat flux (H) of three Kipp and Zonen large aperture scintillometers (LAS) was evaluated with reference to an eddy covariance (EC) system over relatively flat and uniform grassland near Timpas (CO, USA). Other tests have revealed inherent variability between Kipp and Zonen LAS units and bias to overestimate H. Average H fluxes were compared between LAS units and between LAS and EC. Despite good correlation, inter-LAS biases in H were found between 6% and 13% in terms of the linear regression slope. Physical misalignment was observed to result in increased scatter and bias between H solutions of a well-aligned and poorly-aligned LAS unit. Comparison of LAS and EC H showed little bias for one LAS unit, while the other two units overestimated EC H by more than 10%. A detector alignment issue may have caused the inter-LAS variability, supported by the observation in this study of differing power requirements between LAS units. It is possible that the LAS physical misalignment may have caused edge-of-beam signal noise as well as vulnerability to signal noise from wind-induced vibrations, both having an impact on the solution of H. In addition, there were some uncertainties in the solutions of H from the LAS and EC instruments, including lack of energy balance closure with the EC unit. However, the results obtained do not show clear evidence of inherent bias for the Kipp and Zonen LAS to overestimate H as found in other studies.
Keywords: large aperture scintillometer; sensor evaluation; eddy covariance; sensible heat flux large aperture scintillometer; sensor evaluation; eddy covariance; sensible heat flux
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Rambikur, E.H.; Chávez, J.L. Assessing Inter-Sensor Variability and Sensible Heat Flux Derivation Accuracy for a Large Aperture Scintillometer. Sensors 2014, 14, 2150-2170.

AMA Style

Rambikur EH, Chávez JL. Assessing Inter-Sensor Variability and Sensible Heat Flux Derivation Accuracy for a Large Aperture Scintillometer. Sensors. 2014; 14(2):2150-2170.

Chicago/Turabian Style

Rambikur, Evan H.; Chávez, José L. 2014. "Assessing Inter-Sensor Variability and Sensible Heat Flux Derivation Accuracy for a Large Aperture Scintillometer." Sensors 14, no. 2: 2150-2170.



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