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RESEARCH PRODUCT

High resolution rainfall variability in the vineyard: first results from a local scale network in Burgundy.

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4 pages; International audience; Rainfall is a major component of Vitivinicultural Terroirs. In many regions, it controls a large part of water intake byvine and it has an important role in diseases occurrence. Winegrowers often record rainfall with only one or a couple ofrain gauges. Such a sparse coverage might not be accurate enough to capture efficiently the spatial variability ofrainfall, which is a necessary prerequisite for efficient crop management (e.g. for irrigation or spraying decisions, etc.).In order to study high resolution variability of rainfall, we implemented a 40 tipping bucket rain gauges network over anarea of 28 km² in the hilly region of Beaune (France). The mesh size of the network varies from 300 meters to 1,000meters.Between the 19th and the 22nd of January 2012, a rain sequence was recorded in the studied area. Using ConvectiveAvailable Potential Energy (CAPE) data and analysing atmospheric circulation patterns, this sequence has beenclassified as a stratiform precipitation event. During this 4-day span, rain accumulations varied from 11 mm to 21 mm.Geostatistical analysis of the rainfall field indicates that variability increases with distance, in an east-to-west patternmainly according with topography. Such a variation of about 100% on a four day stratiform rain accumulation eventwas unexpected. These observations, if confirmed by further measurements, might confirm that rain gauges network, asusually developed for rainfall monitoring in winegrowing regions, might not be tight enough to capture a strong localvariability. Consequently, water intake and parasites monitoring at the vineyard scale might be strongly biased whenassessed by a single rain gauge.