Terroir 1996 banner
IVES 9 IVES Conference Series 9 The sea breeze: a significant climatic factor for viticultural zoning in coastal wine growing areas

The sea breeze: a significant climatic factor for viticultural zoning in coastal wine growing areas

Abstract

La brise de mer est un facteur climatique important pour le zonage viticole des régions viticoles côtières car l’accélération du vent qui lui est associée l’après midi ainsi que l’augmentation de l’humidité relative et la réduction de la température concomitantes sont significatives pour le fonctionnement de la vigne et, par conséquent, la qualité du raisin et du vin. Le vent, l’humidité relative et la température sont étudiés à partir de données de surface issues de stations météorologiques automatiques situées dans le vignoble au sud ouest de la région du Cap en Afrique du Sud et de simulations numériques sur l’espace étudié afin, d’évaluer le degré de pénétration de la brise de mer et la “limite” de son influence. Les simulations ont été réalisées avec le Regional Atmospheric Modelling System (RAMS) pour trois conditions synoptiques au cours de la période de maturation: un flux à grande échelle de sud, chaud (3/02/2000), un flux de nord très chaud et sec (18/02/2000) et un flux de nord­-ouest frais et humide (19/02/2000). Les résultats des simulations numériques avec une résolution de 1 km montrent que plus les températures sont élevées, plus la baisse des températures générée par la brise de mer est importante. La brise de mer venant de l’Atlantique (Table Bay) le 18/02/2000 a généré une baisse maximale des températures de 6 °C tandis que cette de la False Bay le 3/02/2000 une baisse maximale de 2 °C dans la région viticole de Stellenbosch. Une baisse maximale de 1 °C seulement a été enregistrée lors d’un jour nuageux (19/02/2000).

The sea breeze is an important climatic factor for viticultural zoning in coastal wine producing areas as the associated increase in wind velocity in the afternoon and concomitant increase in relative humidity and reduction in temperature is of significance for vine functioning and, therefore, grape and wine quality. Wind, relative humidity and temperature were studied with the aid of surface data from automatic weather stations in the South Western Cape wine growing area of South Africa as well as numerical simulations over the study domain in order to ascertain the degree of penetration of the sea breeze and to assess the “limit” of its influence. Simulations were performed using the Regional Atmospheric Modelling System (RAMS) for three synoptic conditions during the grape maturation period: a southerly large-scale flow associated with warm temperature (3/02/2000), a northerly large­scale flow associated with hot and dry conditions (18/02/2000) and north-westerly large-scale flow associated with cool and humid conditions (19/02/2000). Results of the numerical simulations performed at a 1-km resolution showed that the warmer the temperature, the greater the temperature decrease induced by the sea breeze. The sea breeze originating from the Atlantic (Table Bay) on 18/02/2000 generated a maximum temperature decrease of
6 °C, while that originating from False Bay on 3/02/2000 generated a maximum temperature decrease of 2 °C in the Stellenbosçh wine producing area. A maximum temperature decrease of only 1 °C was recorded on an overcast day (19/02/2000).

DOI:

Publication date: February 15, 2022

Issue: Terroir 2002

Type: Article

Authors

V. BONNARDOT

ARC Institute for Soil, Climate and Water, Private Bag X5026, 7599 Stellenbosch, South Africa

Contact the author

Keywords

Atmospheric modelling, sea breeze, wine-producing area, South Africa, ripening period

Modélisation atmosphérique, brise de mer, région viticole, Afrique du Sud, période de maturation

Tags

IVES Conference Series | Terroir 2002

Citation

Related articles…

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.

Exploring resilience and competitiveness of wine estates in Languedoc-Roussillon in the recent past: a multi-level perspective

The Languedoc-Roussillon wineries are facing a decline in wine yields particularly PGI yields due to many factors. Climate change is just ones, but is expected to increase in the future. There is also structurally a large heterogeneity of yield profiles among terroirs, varieties and strategies. This work investigates the link between yield, competitiveness and resilience to explore how resilient winegrowers have been in the recent past. To this end two approaches have been combined; (i) an accountancy database analysis at estate scale and (ii) municipality level competitiveness analysis. A new resilience indicator that characterizes the capacity of an estate to absorb yield variation is also defined. The FADN database between 2000 and 2018 of ex-Languedoc-Roussillon (France) and other data are used to analyse the current situation and the past evolution of competitiveness and resilience by type of estate (type of farm: PGI and/or PDO & type of commercialization: bulk and/or bottles). The net margin, which defines competitiveness, is not correlated to yield for all types but depends on the type of commercialization and the level of specialisation. The resilience indicator shows that the net margin of estates specialized in PGI is particularly sensitive to yield declines. We also show that price evolutions seem to compensate the effect of yield losses for the majority of types. Municipality scale analysis shows the links between local pedoclimate, yield, commercialization strategies and price. Overlapping a PDO with a PGI does not always increase a municipality’s PGI competitiveness. It is difficult to make links between causes and effects due to the complexity of the wine production system. Production diversification may be a solution. Resorting to the two level of analysis helps resolving the data gap that is necessary to explore the links between yield and economic performance of the wine estates in the long term.

Delaying irrigation initiation linearly reduces yield with little impact on maturity in Pinot noir

When to initiate irrigation is a critical annual management decision that has cascading effects on grapevine productivity and wine quality in the context of climate change. A multi-site trial was begun in 2021 to optimize irrigation initiation timing using midday stem water potential (ψstem) thresholds characterized as departures from non-stressed baseline ψstemvalues (Δψstem). Plant material, vine and row spacing, and trellising systems were concomitant among sites, while vine age, soil type, and pruning systems varied. Five target Δψstem thresholds were arranged in an RCBD and replicated eight times at each site: 0.2, 0.4, 0.6, 0.8, and 1.0 MPa (T1, T2, T3, T4, and T5, respectively). When thresholds were reached, plots were irrigated weekly at 70% ETc. Yield components and berry composition were quantified at harvest. To better generalize inferences across sites, data were analyzed by ANOVA using a mixed model including site as a random factor. Across sites, irrigation was initiated at Δψstem = 0.24, 0.50, 0.65, 0.93, and 0.98 MPa for T1, T2, T3, T4, and T5, respectively. Consistent significant negative linear trends were found for several key yield and berry composition variables. Yield decreased by 12.9, 15.9, 19.5, and 27.4% for T2, T3, T4, and T5, respectively, compared to T1 (p < 0.0001) across sites that were driven by similarly linear reductions in berry weight (p < 0.0001). Comparatively, berry composition varied little among treatments. Juice total soluble solids decreased linearly from T1 to T5 – though only ranged 0.9 Brix (p = 0.012). Because producers are paid by the ton, and contracts simply stipulate a target maturity level, first-year results suggest that there is no economic incentive to induce moderate water deficits before irrigation initiation, regardless of vineyard site. Subsequent years will further elucidate the carryover effects of delaying irrigation initiation on productivity over the long term.

A predictive model of spatial Eca variability in the vineyard to support the monitoring of plant status

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...