Abstract

The eddy covariance (EC) technique is a standard reference for estimating carbon and water vapor exchanges in regional and local flux networks (Baldocchi, 2003). Eddy covariance uses high frequency measurements of scalars (water vapor, temperature, etc.) and the vertical component of wind speed to determine fluxes. The method requires sonic anemometers and hygrometers or gas analyzers (Kaimal, Finnigan, 1994; Shaw, Snyder, 2003).
The surface renewal (SR) method for estimating fluxes from canopies involves high frequency measurements of scalar variables. The high frequency data are analyzed for ramp-like characteristics and the amplitude and inverse ramp frequency are used in basic energy or mass conservation equations to estimate fluxes. In previous papers, good results were reported for estimating sensible heat flux (H) over a variety of vegetated surfaces (Paw U et al., 1995; Snyder et al., 1996; Spano et al., 1997a, 1997b; Anandakumar, 1999; Spano et al., 2002). Little information, however, is available on using SR to estimate latent (LE) and CO₂ flux (Fc) density (Paw U et al., 1995; Spano et al., 2002; Spano et al., 2004). The advantage in using the SR rather than the EC method is that, after calibration, a sonic anemometer is not required.
The aim of this worth was the assessment of energy and mass exchanges between grapevine canopy surface and the atmosphere using the EC and SR methods.

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