A simulation model for the daily course of grape berry temperature.

Grape temperature is a crucial driving variable for the wide variety of biochemical processes that are carried out during the ripening of grapes and which determine the quality of wine. A mechanistic modelling approach to the simulation of grape temperature must be founded on the resolution of the energy balance equation referred to the surface of grapes. In this perspective the net radiation triggers three different flows: sensible heat flow, latent heat flow and heat flow into the grapes, which store a part of the total energy exchanged. A model of this kind was developed and parameterised by the authors. The validation activity referred to grape temperatures gauged in two Nebbiolo vineyards in 2004 is presented and the consequent results are discussed. A test example referring to some varieties of Friuli Venezia Giulia is also presented. Finally a possible output employment for management is presented.