Cascade modelling approach for daily global radiation estimation and precision viticulture applications in the Chianti area

A cascade modelling approach was used to estimate global solar radiation reaching vineyard green wall during the year. An open source global scale radiation model (r.sun), a local scale model based on temperature excursion (DC) and a vineyard 3D light use efficiency model (Riou) were integrated into a proprietary GIS (SGx) for environmental and agricultural evaluations. All the models was implemented in c-sharp language under .net environment, integrating their functions for the obtainment of multi-scale information. Their tuning and preliminary outputs validation were performed by means of different series of solar radiation data, available for the Chianti region, evaluating model validity at different spatial and temporal resolutions. In this paper adopted procedures and algorithms are presented and a deeper analysis of the results of validation is given. Proposed method seems to be able to produce a good estimation of solar radiation reaching considered surface (area, soil, leaves, etc.), with some differences depending on weather and sky conditions. Further efforts should be done to improve model reliability and its capability to describe actual daily radiative conditions. At the moment, produced information could already be used for different purposes including evaluation on technical long and short term choices for Precision Viticulture (PV).