BerryTone—A simulation model for the daily course of grape berry temperature

Grape temperature is a crucial driving variable for the wide variety of biochemical and physiological processes taking place during berry ripening which determine the oenological quality potential of grapes. The aim of this work is to develop, calibrate and validate a model simulating surface berry temperature (BerryTone), taking into account the effect of different sun exposures and leaf shadings. BerryTone has been developed using a mechanistic approach founded on the energy balance and it is driven only by maximum and minimum daily air temperatures. Calibration and validation have been carried out on independent dataset in Northern Italy during 2005 and 2006. In order to evaluate the effectiveness of the model in other environmental conditions, a further test on a time series from 2008 in Central Italy was also carried out. Final results show that the model satisfactorily described berry thermal behaviour under solar forcing for different exposures, improving upon the description usually given by air temperature.