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…

Adapting the vineyard to climate change in warm climate regions with cultural practices

Since the 1980s global regime shift, grape growers have been steadily adapting to a changing climate. These adaptations have preserved the region-climate-cultivar rapports that have established the global trade of wine with lucrative economic benefits since the middle of 17th century. The advent of using fractions of crop and actual evapotranspiration replacement in vineyards with the use of supplemental irrigation has furthered the adaptation of wine grape cultivation. The shift in trellis systems, as well as pruning methods from positioned shoot systems to sprawling canopies, as well as adapting the bearing surface from head-trained, cane-pruned to cordon-trained, spur-pruned systems have also aided in the adaptation of grapevine to warmer temperatures. In warm climates, the use of shade cloth or over-head shade films not only have aided in arresting the damage of heat waves, but also identified opportunities to reduce the evapotranspiration from vineyards, reducing environmental footprint of vineyard. Our increase in knowledge on how best to understand the response of grapevine to climate change was aided with the identification of solar radiation exposure biomarker that is now used for phenotyping cultivars in their adaptability to harsh environments. Using fruit-based metrics such as sugar-flavonoid relationships were shown to be better indicators of losses in berry integrity associated with a warming climate, rather than solely focusing on region-climate-cultivar rapports. The resilience of wine grape was further enhanced by exploitation of rootstock × scion combinations that can resist untoward droughts and warm temperatures by making more resilient grapevine combinations. Our understanding of soil-plant-atmosphere continuum in the vineyard has increased within the last 50 years in such a manner that growers are able to use no-till systems with the aid of arbuscular mycorrhiza fungi inoculation with permanent cover cropping making the vineyard more resilient to droughts and heat waves. In premium wine grape regions viticulture has successfully adapted to a rapidly changing climate thus far, but berry based metrics are raising a concern that we may be approaching a tipping point.

Extreme canopy management for vineyard adaptation to climate change: is it a good idea?

Climate change constitutes an enormous challenge for humankind and for all human activities, viticulture not being an exception. Long-term strategic changes are probably needed the most, but growers also need to deal with short-term changes: summers that are getting progressively warmer, earlier harvest dates and higher pH in musts and wines. In the last 10-15 years, a relevant corpus of research is being developed worldwide in order to evaluate to which extent extreme canopy management operations, aimed at reducing leaf area and, thus, limiting the source to sink ratio, could be useful to delay ripening. Although extreme canopy management can result in relevant delays in harvest dates, longer term studies, as well as detailed analysis of their implications on carbohydrate reserves, bud fertility and future yield are desirable before these practices can be recommended.

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

Local adaptation tools to ensure the viticultural sustainability in a changing climate

[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"...

Modelling vine water stress during a critical period and potential yield reduction rate in European wine regions: a retrospective analysis

Most European vineyards are managed under rainfed conditions, where seasonal water deficit has become increasingly important. The flowering-veraison phenophase represents an important period for vine response to water stress, which is seldomly thoroughly evaluated. Therefore, we aim to quantify the flowering-veraison water stress levels using Crop Water Stress Indicator (CWSI) over 1986–2015 for important European wine regions, and to assess the respective potential Yield Lose Rate (YLR). Additionally, we also investigate whether an advanced flowering-veraison phase may help alleviating the water stress with improved yield. A process-based grapevine model STICS is employed, which has been extensively calibrated for flowering and veraison stages using observed data at 38 locations with 10 different grapevine varieties. Subsequently, the model is being implemented at the regional level, considering site-specific calibration results and gridded climate and soil datasets. The findings suggest wine regions with stronger flowering-veraison CWSI tend to have higher potential YLR. However, contrasting patterns are found between wine regions in France-Germany-Luxembourg and Italy-Portugal-Spain. The former tends to have slight-to-moderate drought conditions (CWSI<0.5) and a negligible-to-moderate YLR (<30%), whereas the latter possesses severe-to-extreme CWSI (>0.5) and substantial YLR (>40%). Wine regions prone to a high drought risk (CWSI>0.75) are also identified, which are concentrated in southern Mediterranean Europe. An advanced flowering-veraison phase may have benefited from cooler temperatures and a higher fraction of spring precipitation in wine regions of Italy-Portugal-Spain, resulting in alleviated CWSI and moderate reductions of YLR. For those of France-Germany-Luxembourg, this can have reduced flowering-veraison precipitation, but prevalent alleviations of YLR are also found, possibly because of shifted phase towards a cooler growing season with reduced evaporative demands. Overall, such a retrospective analysis might provide new insights towards better management of seasonal water deficit for conventionally vulnerable Mediterranean wine regions, but also for relatively cooler and wetter Central European regions.