Viticultural agroclimatic cartography and zoning at mesoscale level using terrain information, remotely sensed data and weather station measurements. Case study of Bordeaux winegrowing area

Abstract : Climate is a key variable for grapevine development and berry ripening processes. At mesoscale level, climate spatial variations are often determined empirically, as weather station networks are generally not dense enough to account for local climate variations. In this study, climate spatial variations of Bordeaux winegrowing area were assessed by means of solar radiation cartography using satellite sensing and Digital Elevation Model (DEM) information, daily temperature interpolation using weather station and terrain information, spatialized rainfall using rain gauge data and kriging techniques. Temperature and solar radiation data were used to generate evapotranspiration maps at daily time step. Spatialized data was used to characterize the production potential of several zones of Bordeaux winegrowing areas, according to their agroclimatic characteristics. Temperature differences within Bordeaux vineyards induce considerable discrepancies in vine phenology, as is shown by means of a degree.day model. Solar radiation data and potential evapotranspiration are mostly governed by terrain characteristics (slope and aspect). Rainfall data spatial patterns indicate that the north-western part of Bordeaux vineyards is recurrently drier and the south-western receives higher rainfall amounts during the grapevine growing season. However, spatial distribution of summer rainfall events changes considerably from one year to another. The results of this study offer useful information to adapt grapevine cultivars and vineyard management to local climate.