Spatial modelling of grapevine phenology to inform adaptation of viticulture to a warmer climate — Australian Meteorological and Oceanographic Society

Spatial modelling of grapevine phenology to inform adaptation of viticulture to a warmer climate (#107)

Andrew Hall 1
  1. Charles Sturt University, Thurgoona, NSW, Australia

Climate is arguably the most important component of viticultural terroir. Averaged growing season temperature, in particular, is a key consideration during vineyard establishment and subsequent management due its varied effect on the phenology of different winegrape cultivars. Spatial modelling of grapevine phenology, using raster maps of temporally averaged climate data, provides indicative terroir suitability for winegrape production across large areas. Modifying the base temperature maps, by adding GCM-generated temperature anomalies, winegrape growing conditions can be additionally modelled across different warming scenarios.

Inferred projected phenological changes may require significant adaptive vineyard management. Under warmer conditions, veraison (berry ripening) is projected to occur during a warmer time of year, causing an undesirably short ripening period. An earlier budbreak may increase the probability of exposure to early frosts, leading to potential falls in overall productivity. An extended post-harvest period, where grapevines continue to photosynthesise longer after harvest, may lead to an increase in stored carbohydrates to be utilised in the following season.

Winegrape growers are able to use modelling outputs to improve their long-term decision making. A valuable approach is using climate analogues, where a vineyard manager investigates projected future temperatures of their resident region to those that are similar to recent conditions of another region. By considering what varieties and cultural practices work well in the analogue region, the winegrape grower is better equipped to manage change. For example, different winegrape varieties tend to be suited to particular temperature regimes; grapevine varieties for new vineyards can be selected to better suit the projected climate.

While recent modelling of grapevine phenology has broadly enabled winegrape producers plan for a warmer climate, additional quantification of productivity risks is needed, including spatial data around the projected frequency of early season frosts, extreme heat events at key phenological stages, and stored water availability for irrigation.

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