424 Am. J. Enol. Vitic. 63:3 (2012) Meteorological variables play a crucial role in vegetative- productive responses of the vine (Vitis vinifera L.) in terms of quantity and quality of grapes. Climate is a key parameter in the defnition of terroir, driving basic cultivation choices such as the trellis system and pruning options. Many indices based on climate data (Winkler 1974, Branas 1974, Huglin 1978, Gladstone 1992, Fregoni et al. 2002) have been widely used in viticultural zoning studies, particularly with respect to the interaction between environmental parameters and wine quality, to describe and identify an area’s productive potential and risk and to provide a synthetic description of a single season. While these indices provide an appropriate representation of regional climate conditions, they tend to lose effectiveness in representing intravineyard spatial vari- ability because of the poor representation of the dynamics of the daily meteorological cycle that is at the base of mi- croscale climate variability. Indeed, vineyard microclimate is demonstrated to signifcantly affect grape quality and canopy microclimate is known to have a signifcant variability at the intravineyard scale (Nicholas et al. 2011). In particular, solar radiation and temperature are the me- teorological parameters that mainly infuence the composi- tion and metabolism of grapes, as they are directly related to the synthesis of sugar and to the secondary metabolites that characterize grape quality (Spayd et al. 2002). In precision viticulture, the knowledge of variability within the vineyard and the factors underlying this variability are crucial in im- plementing best management practices and, in this sense, the understanding of how management practices affect canopy microclimate requires further investigation. The newer tech- nologies for micrometeorological monitoring, such as wire- less sensor networks (WSN), allowing high spatial and time 1 Istituto di Biometeorologia, Consiglio Nazionale delle Ricerche (IBIMET- CNR), Via Giovanni Caproni 8, 50145 Firenze, Italy; 2 Dipartimento Colture Arboree, Università di Torino, Via Leonardo da Vinci 44, 10095 Grugliasco, Italy; and 3 Consorzio Tuscania, Via Sangallo 43, località Sambuca, Tavarnelle Val di Pesa, Italy. *Corresponding author (email: a.matese@ibimet.cnr.it; tel: +390553033711; fax+39055308910) Acknowledgments: The authors thank Francesco Sabatini, Lorenzo Albanese, Leandro Rocchi, and Tiziana De Filippis of IBIMET-CNR for their support, especially in the stages of collecting and processing data; and Alessandra Biondi Bartolini, Manuel Pieri, Marco Valentini, and the staff of the Consorzio Tuscania S.r.l., which provided technical and fnancial support for the work. The entire Consorzio Tuscania data set is available on request and accessible from the Tuscania GeoDB at www.consorziotuscania.it. Supplemental data is freely available with the online version of this article at www.ajevonline.org. Manuscript submitted Nov 2011, revised Apr 2012, accepted May 2012. Pub- lication costs of this article defrayed in part by page fees. Copyright © 2012 by the American Society for Enology and Viticulture. All rights reserved. doi: 10.5344/ajev.2012.11117 Technical Brief Infuence of Canopy Management Practices on Vineyard Microclimate: Defnition of New Microclimatic Indices Alessandro Matese, 1,2 * Alfonso Crisci, 1 Filippo Salvatore Di Gennaro, 1 Edoardo Fiorillo, 1 Jacopo Primicerio, 1 Piero Toscano, 1 Francesco Primo Vaccari, 1 Stefano Di Blasi, 3 and Lorenzo Genesio 1 Abstract: Meteorological parameters have a crucial infuence on grapevine (Vitis vinifera L.) production quantity and quality. Most of the commonly used bioclimatic indices are not appropriate to represent intravineyard micro- meteorological variability, in particular the subdaily dynamics that are important in grape maturation processes. The aim of this research was to compile a new set of micrometeorological indices and evaluate their capacity to discriminate the differences in the microclimatic daily cycle induced by different canopy management techniques, based on a statistical data set of three years (2008, 2009, 2010) of hourly data of cluster internal temperature, canopy air temperature, and solar radiation intercepted by the cluster. Data was collected in four vineyards planted with Sangiovese and Cabernet Sauvignon, located in three climatic zones of Tuscany (Italy). Starting from this data set, some new micrometeorological indices were defned using two different criteria for subdaily time segmentation: static, based on fxed hourly intervals, and dynamic, based on solar height daytime segmentation. Results showed that indices based on subdaily data better provide a better representation of vineyard microclimate than daily indices and are able to highlight microclimatic differences induced by canopy management practices. The indices more sensitive to treatments are those related to the solar radiation intercepted by the cluster parameter and relative to the Broad Daylight Index, which represent the average of micrometeorological parameters in the middle hours of the day. The proposed indices enhance the characterization of micrometeorological conditions induced by different canopy management practices and, therefore, the assessment of the within-vineyard spatial variability of environ- mental parameters. Key words: canopy microclimate, climatic indicators, wireless sensor network (WSN), micrometeorology, grapevine