Project title
Atmospheric modelling with application for the zoning of viticultural regions

Project leader
Engelbrecht, C

Institution
Institute for Soil, Climate and Water

Project description
This project started in April 2003. A meso-scale atmospheric modelling system (RAMS) is being used to identify locations according to their potentiality of meeting the climatic requirements for optimum physiological performance of the vine.
The climate of the Stellenbosch region is the first one to be assessed.

Numerical simulations were performed with the RAMS atmospheric modelling system and 4 nested grids (resolution of 25 km, 5 km, 1 km and 200 m). Altitude, soil and vegetation data for each grid were extracted from the ARC-ISCW GIS databank. Numerical simulations (18 days during February 2000) were performed at the Laboratoire de Météorologie Physique in France (foreign visit from 23 June to 12 July 2003). Horizontal and vertical cross-sections for temperature, relative humidity and wind were plotted for different times of the day and for specific days of climatic interest. Modelled hourly data were extracted from the analysis files into ASCI files in order to produce mean hourly fields for the 16-day period (temperature, relative humidity; wind speed and radiation). Differences between modelled and observed data were minor.
Daily weather bulletins were used to classify the synoptic weather situations over the Western Cape. Four growing seasons (1999-2000 to 2002-2003) were examined and classified in order to assess the frequency of the types of weather for each month of the growing season and to select days of climatic interest to model in the future.

Poster(s)
1. Bonnardot, V, Cautenet, S, Planchon, O, Du Preez, C and Carey, V A. 2001. Modelisation atmospherique meso-echelle: un outil pour l'identification des terroirs viticoles en Afrique du Sud. International Assocation for Climatology Congress, Seville, Spain.
2. Atmospheric modeling and application to viticulture: preliminary results in the Stellenbosch region. 2003. South African Society for Atmospheric Science (SASAS) Conference, 13-14 October, Pretoria. South Africa.
3. Weather classification over the Western Cape (February, 1996 - 2000) and viticultural implications in the Stellenbosch wine district. 2004. Joint International Conference on Viticultural Zoning, 15-19 November. South Africa.
4. CCAM vs RAMS: A comparison to weigh the pros and cons of each model. 2004. South African Society for Atmospheric Sciences Conference, 4-6 October. Bloemfontein, South Africa.

Presentation(s)
1.  Bonnardot, V and De Villiers, F S. 1997. Sea-breeze in the Stellenbosch-Klein Drakenstein wine producing district. 22nd National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.
2.  De Villiers, F S. 1997. The use of a geographic information system (GIS) in the selection of wine cultivars for the specific areas by using temperature climatic models. 22nd OIV World Vine and Wine Congress, Buenos Aires, Argentinia.
3. De Villiers, F S. 1997. Terreinkeuse. Druifproduksie met spesifieke wyndoelwit. South African Society for Enology and Viticulture Short Course, 4 September, Parow, South Africa.
4. Bonnardot, V, Carey, V A and Schmidt, A. 1999. The effect of mesoclimate on Sauvignon blanc aroma profiles in the Stellenbosch wine growing area (1996-1999). 24th National Congress of the South African Society of Enology and Viticulture, Somerset West. South Africa.
5.  Carey, V A. 1999. The spatial characterisation of viticultural terrains in the Bottelaryberg and Helderberg wine growing area. 24th National Congress of the South African Society for Enology and Viticulture, Somerset West. South Africa.
6.  Schmidt, A, Bonnardot, V and Carey, V A. 1999. The influence of terrain selection on Cabernet Sauvignon. 24th National Congress of the South African Society for Enology and Viticulture, November, Somerset West. South Africa.
7.  Bonnardot, V, Cautenet, S, Planchon, O and Carey, V A. 2000. Sea breeze numerical simulations in the Stellenbosch wine growing area. 2nd International Congress of the South African Society for Enology and Viticulture, November, Cape Town. South Africa.
8. Carey, V A. 2000. The delimitation of macro-climatic regions in the Western Cape with the aid of a geographic information system and the determination of their potential for various cultivars. Office International de la Vigne et du Vin. Expert group-Vitivinicultural zoning.
9.  Carey, V A and Bonnardot, V. 2000. Spatial characterisation of terrain units in the Bottelaryberg-Simonsberg-Helderberg wine growing area, South Africa. 3rd International Symposium of Viticultural Zoning, May, Puerto de la Cruz, Tenerife.
10.  Bonnardot, V, Cautenet, S, Planchon, O, Du Preez, C and Carey, V A. 2001. Identification of climatic limits and coolest areas resulting from the sea breeze effect in the Stellenbosch/Helderberg Winegrowing area. 26th National Congress of the South African Society for Enology and Viticulture, Somerset West. South Africa.
11. Bonnardot, V, Cautenet, S, Planchon, O and Carey, V A. 2001. Sea breeze numerical simulation in the Western Cape Province: a means to identify wine growing areas affected by cool temperatures, high humidity and strong winds. 25th National Congress of the South African Society for Enology and Viticulture, Cape Town. South Africa.
12. Carey, V A. 2001. The terroir effect in red wine production. A strategic focus on South African red wine workshop. Somerset West.
13.  Carey, V A. 2001. The terroir effect in red wine production. A strategic focus on South African red wine workshop. Somerset West.
14. Carey, V A, Archer, E and Saayman, D. 2001. Spatial characterisation of natural terroir units for viticulture in the Bottelaryberg-Simonsberg-Helderberg wine growing area. 25th National Congress of the South African Society for Enology and Viticulture, Somerset West.
15.  Bonnardot, V, Dyson, L, Cautenet, S, Planchon, O, Du Preez, C and Carey, V A. 2001. Numerical simulations of a sea breeze in the Stellenbosch area. South African Society for Atmospheric Science Congress, Cape Town. South Africa.
16. Bonnardot, V, Cautenet, S, Planchon, O, Du Preez, C and Carey, V A. 2001. Sea breeze numerical simulations at a 200m-grid resolution in the Stellenbosch - Helderberg wine growing area. 25th National Congress for the South African Society for Enology and Viticulture, Somerset West. South Africa.
17.  Carey, V A, Bonnardot, V M F, Schmidt, A and Theron, J C D. 2001. The interaction between vintage, vineyard site (mesoclimate) and wine aroma of Vitis vinifera L. cvs. Sauvignon blanc, Chardonnay and Cabernet Sauvignon in the Stellenbosch-Klein Drakenstein wine growing area, South Africa (1996-2000). 26th OIV World Vine and Wine Congress, October 2001, Adelaide, Australia.
18.  Carey, V A. 2002. Cultivar X environment interaction: example of Cabernet Sauvignon in the Stellenbosch-Drakenstein wine growing area, South Africa. OIV Group d'Experts: Zonage Vitivinicole, March, Paris. France.
19. Carey, V A, Archer, E and Saayman, D. 2002. Identification of natural terroir units for viticulture, Stellenbosch, South Africa. International Symposium of Zonage Vitivinicole, Avignon.
20. Carey, V A and Bonnardot, V. 2002. A viticultural perspective of meso-scale atmospheric modelling in the Bottelaryberg-Simonsberg-Helderberg wine growing area (South Africa). XXVIIth World Congress of Vine and Wine, Bratislava.
21.  Bonnardot, V. 2002. The sea breeze: A significant climatic factor for viticultural zoning in coastal wine growing areas. IVth International Symposium Viticultural Zoning. June, Avignon, France.
22. Bonnardot, V, Cautenet, S, Planchon, O, Du Preez, C and Carey, V A. 2002. Atmospheric modelling: A tool to assess the sea breeze effect in the south Western Cape wine growing area. 27th World Congress Vine and Wine (OIV), June, Bratislava, Slovenia.
23. Hunter, J J and Bonnardot, V. 2002. Climate requirements for optimal physiological processes: a factor in viticulture zoning . IVth International Symposium Viticulture Zoning, 17-20 June, Avignon, France.
24. Rosewell, D I and Strydom, J J. 2003. Management and control of fungal diseases in vineyards using automatic weather station networks. South African Society for Atmospheric Science Congress, October, Pretoria. South Africa.
25.  2003. Winetech Terroir Meeting, 18 September, Stellenbosch.
26.  2004. ARC-ISCW Seminar, 15 March, Pretoria.
27. Classification of the synoptic conditions over the South Western Cape during the ripening period of grapes. (1996-2000). 2004. Annual Conference of the South African Society for Atmospheric Sciences, 24-25 May, Cape Town.
28. Atmospheric modelling: A tool to identify locations best suited for vine cultivation. Preliminary results in the Stellenbosch region. 2004. Joint International Conference on Viticultural Zoning, 15-19 November.
29. 2005. Winetech Terroir Programme Meeting. 28 April, ARC Infruitec Nietvoorbij, Stellenbosch, South Africa.
30. Comparison and verification of fine resolution atmospheric simulations by CCAM and RAMS over the Stellenbosch wineries. 2006. South African Society for Atmospheric Sciences Conference, 4-6 October. Bloemfontein, South Africa.
31. Fine resloution atmospheric modelling over the Stellenbosch wine producing region. 2007. Combined Congress, 22-25 January. Badplaas.

Final report
http://www.sawislibrary.co.za/dbtextimages/EngelbrechtC.pdf

Bonnardot, V, Planchon, O, Cautenet, S, Carey, V. 2001. Sea breeze mechanisms and observations of its effects in the Stellenbosch wine producing area. WineLand. Mnth Oct p. 107-113

Article

Bonnardot, V M F, Planchon, O, Carey, V A, Cautenet, S. 2002. Diurnal wine, relative humidity and temperature variation in the Stellenbosch Groot Drakenstein wine growing areas. South African Journal of Enology + Viticulture. v. 23 n. 2 p. 62-71

Bonnardot, V M F, Planchon, O, Cautenet, S. 2005. Sea breeze development under an offshore synoptic wind in the south Western Cape and implications for the Stellenbosch wine producing area. Journal of Theoretical and Applied Climatology. v. 81 n. 3-4 p. 1434-1483

Du Preez, C. 2007. A mesoscale investigation of the sea breeze in the Stellenbosch wine growing district. M.Sc.

Thesis

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