The energy balance method was used to characterize the hourly variation of the net radiation, latent and sensible fluxes and soil heat flux on a mature vineyard grown at Jundiaí, São Paulo, Brazil. The grapevines, cv. Niagara Rosada, in the vineyard were wrapped to trellis wires, creating compact hedgerows 2 m apart, 1.7 m height and 0.4 wide, with the foliage 1m above the soil surface. Also, the net and incoming radiation relationships and the partioning of the available energy to the system into latent and heat flux, and soil heat flux were determined for the vineyard. During a sunny day (dry period) the latent heat flux was 44% of the net radiation and the sensible heat flux, 48%. However during a rainy day, the latent heat flux was 86% of the net radiation and the sensible heat flux, 21%. During a sunny day, after the occurrence of rain, the latent and sensible heat fluxes were, respectively, 68% and 29% of the net radiation. The soil heat flux was 5.7 an 1.3% of the net radiation, for bare soil and mulched rows, respectively.
grapevine; net radiation; soil heat flux; latent and sensible fluxes
