Handbook for Irrigation of Wine Grapes in South Africa

Figure 1.3

1 500 1 700 1 900 2 100 2 300 2 500 2 700 2 900

Klawer

Region V

Vredendal

Lutzville

Region IV

GDD (ºC)

Ebenaeser

Region III

R 2 = 0.9529

0

10

20

30

40

50

Distance (km)

FIGURE 1.3. Effect of distance to the Atlantic Ocean on wine quality potential in the Lower Olifants River region according to the GDD as proposed by Bruwer (2010).

1.3.2 MEAN FEBRUARY TEMPERATURE Since temperature plays an important role in determining wine quality, analysis of long term weather data can be used to demarcate the potential wine quality of a region (Bruwer, 2010 and references therein). The MFT classification, i.e. for the warmest month of the year, was adapted by De Villiers et al . (1996) for the Western Cape wine regions (Table 1.5). The variability of MFT in the Coastal region of the Western Cape is shown in Figure 1.4.

TABLE 1.5. Wine quality potential classification for the Western Cape according to the MFT as proposed by De Villiers et al . (1996).

MFT (ºC)

Region

Wine quality potential

17 - 18.9

Cold

High quality white table wine

19 - 20.9

Cool

High quality white and red table wine

21 - 22.9

Moderate

High quality red table wine

23 - 24.9

Warm

Low acid, high pH

> 25

Very warm

Low acid, high pH

It was also shown that altitude and the proximity of the Atlantic Ocean affect the MFT in the Western Cape Coastal region over distances as far as ca. 60 km inland (Myburgh, 2005). The effects of sea breezes play a prominent role in the

20 CHAPTER 1 – CLIMATE