Traces of high frequency temperature data above and within plant canopies exhibit ramp-like shapes that are related to coherent structures. The mean ramp characteristics (amplitude, a, and inverse ramp frequency, l+s), during a measurement period, are used in surface renewal (SR) analysis (Paw U and Brunet, 1991) to estimate sensible heat flux density (H) using a fundamental energy balance equation (Paw U et al., 1995; Snyder et al., 1996; Spano et al., 1997). The use of H values from SR analysis in conjunction with measured net radiation (Rn) and soil heat flux density (G) provides for a portable and relatively inexpensive method to estimate latent heat flux density (?E). In previous experiments, the plant canopies studied were variable in height, but all had dense foliage. In sparse grape vineyard canopies, the ground is only partially covered, and differential heating of the air volume below the measurement height is expected. The objectives of this study were to evaluate (1) the SR method for grapevines and (2) the need for a calibration factor to account for uneven heating of the mean air volume under a measurement level.

Surface Renewal analysis for sensible and latent heat flux density over sparse canopy

Duce P;
1998

Abstract

Traces of high frequency temperature data above and within plant canopies exhibit ramp-like shapes that are related to coherent structures. The mean ramp characteristics (amplitude, a, and inverse ramp frequency, l+s), during a measurement period, are used in surface renewal (SR) analysis (Paw U and Brunet, 1991) to estimate sensible heat flux density (H) using a fundamental energy balance equation (Paw U et al., 1995; Snyder et al., 1996; Spano et al., 1997). The use of H values from SR analysis in conjunction with measured net radiation (Rn) and soil heat flux density (G) provides for a portable and relatively inexpensive method to estimate latent heat flux density (?E). In previous experiments, the plant canopies studied were variable in height, but all had dense foliage. In sparse grape vineyard canopies, the ground is only partially covered, and differential heating of the air volume below the measurement height is expected. The objectives of this study were to evaluate (1) the SR method for grapevines and (2) the need for a calibration factor to account for uneven heating of the mean air volume under a measurement level.
1998
Istituto di Biometeorologia - IBIMET - Sede Firenze
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/185121
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