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…

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

The use of rootstock as a lever in the face of climate change and dieback of vineyard

As viticulture faces challenges such as climate change or vineyard dieback, the choice of the variety and rootstock becomes more and more crucial. To study rootstock levers in the Bordeaux region, a parcel of Cabernet Sauvignon (CS) was planted with four rootstocks in 2014. Twenty repetitions of each of the following four rootstocks were set up: 101-14 MGt, Nemadex AB, 420A MGt and Gravesac. The number of bunches, yields and pruning weights of the vine shoots were measured individually on 240 vines from 2017 to 2021. Since 2020, nitrogen status assessed by assimilable nitrogen level, hydric status assessed by δ13C and berry maturity were measured on 80 samples taken from 20 repetitions of the four rootstocks. A lower yield was measured for CS grafted onto Nemadex AB due to the lower number of bunches and the lower weight of berries. The differences between the other three rootstocks are small, but CS grafted onto 420A MGt was the most productive. The CS grafted onto Nemadex AB had the lowest pruning weight while 101-14 MGt had the highest. In 2020, δ13C showed a more moderate water stress with 101-14 MGt and 420A MGt than with Nemadex AB. Surprisingly, the Gravesac was under more stress than the 101-14 MGt. The nitrogen status in the berries was better for Nemadex AB but this was perhaps due to the significantly lower weight of the berries.Rootstock 101-14 MGt attained the highest accumulation of sugars in the berries while 420A MGt allows to preserve higher acidity. The parcel is still young which may explain some of the results. These measures must therefore be continued over the next several years to fully assess the effects of these rootstocks on the development of the vines and the quality of the production under new climatic conditions.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

Organic recycled mulches in sustainable viticulture: assessment of spontaneous plants communities and weed coverage

In recent years, developing more efficient and sustainable viticulture management has been essential due to the impact of climate change in semiarid regions. For this reason, the use of recycled organic mulching (ROM) in the vineyard has become an interesting strategy to cope with water stress, isolated soil from extreme temperatures and improving soil humidity, control the presence of weeds and therefore reduce the inputs of herbicides and improve soil fertility. This work aimed to analyse the effect of three different organic mulches [straw (S), grape pruning debris (GPD) and spent mushroom compost (SMC)] and two traditional soil management techniques [herbicide (H) and interrow (IN)] on weed coverage and the spontaneous plant communities’ presence. Data sampling was collected throughout the vine vegetative cycle of 2021 in La Rioja, Spain. The different soil management techniques had a clear effect on weed coverage and his development during the vine vegetative cycle. SMC and H were the treatments with the highest and the lowest coverage percentage, respectively. IN had a delayed weed emergence at the beginning of the vine vegetative cycle, but finally it reached maximum values nearby SMC. GPD and S had similar effects on weed emergence, reaching 25-30% of the maximum coverage values. A total of 29 herbaceous species were identified during the vegetative cycle, some of them very isolated and occasional. Principal component analysis (PCAs) showed a good association between spontaneous species and treatments, furthermore, specific species-treatment associations were found. Moreover, three clear groups of herbaceous communities were identified by cluster analysis. This study provides interesting information about the effect of different alternative soil management on herbaceous plant coverage and weed species communities which could contribute to making more sustainable viticulture.

Aromatic maturity is a cornerstone of terroir expression in red wine

Harvesting grapes at adequate maturity is key to the production of high-quality red wines. Enologists and wine makers define several types of maturity, including technical maturity, phenolic maturity and aromatic maturity. Technical maturity and phenolic maturity are relatively well documented in the scientific literature, while articles on aromatic maturity are scarcer. This is surprising, because aromatic maturity is, without a doubt, the most important of the three in determining wine quality and typicity (including terroir expression). Optimal terroir expression can be obtained when the different types of maturity are reached at the same time, or within a short time frame. This is more likely to occur when the ripening takes place under mild temperatures, neither too cool, nor too hot. Aromatic expression in wine can be driven, from low to high maturity, by green, herbal, fresh fruit, ripe fruit, jammy fruit, candied fruit or cooked fruit aromas. Green and cooked fruit aromas are not desirable in red wines, while the levels of other aromatic compounds contribute to the typicity of the wine in relation to its origin. Wines produced in cool climates, or on cool soils in temperate climates, are likely to express herbal or fresh fruit aromas; while wines produced under warm climates, or on warm soils in temperate climates, may express ripe fruit, jammy fruit or candied fruit aromas. Growers can optimize terroir expression through their choice of grapevine variety. Early ripening varieties perform better in cool climates and late ripening varieties in warm climates. Additionally, maturity can be advanced or delayed by different canopy management practices or training systems.