Handbook for Irrigation of Wine Grapes in South Africa

TABLE 1.2. Description of Köppen climate symbols and defining criteria according to Peel et al. (2007).

1st 2nd 3rd Description

Criteria

A

Tropical

Not applicable to South African grape growing regions Mean annual precipitation < 10 x precipitation threshold (1) Mean annual precipitation < 5 x precipitation threshold Mean annual precipitation ≥ 5 x precipitation threshold

B

Arid

W – Desert

S

– Steppe

Mean annual temperature ≥ 18

h – Hot

k – Cold

Mean annual temperature < 18

> 10 and 0 < coldest month

C

Temperate

Hottest month T mean

mean temperature < 18

s

– Dry summer

Precipitation in driest month of summer < 40 and precipitation in driest summer month < (precipi- tation in wettest winter month ÷ 3) Precipitation in driest winter month < (precipita- tion in wettest summer month ÷ 10)

w

– Dry winter

f

– Without dry season Not (Cs) or (Cw)

Hottest monthly mean temperature ≥ 22

a – Hot summer

b – Warm summer

Not (a) and number of months where mean tem- perature is above 10 ≥ 4 Not (a) or (b) and 1 ≤ number of months where T mean is above 10 < 4 Not applicable to South African grape growing regions Not applicable to South African grape growing regions

c – Cold summer

D

Cold

E

Polar

(1) Precipitation threshold (P threshold

) varies according to the following rules: If 70% of mean

annual precipitation (MAP) occurs in winter then P threshold (MAT), if 70% of MAP occurs in summer then P threshold

= 2 x mean annual temperature = 2 x MAT + 28, otherwise P threshold =

2 x MAT + 14.

16 CHAPTER 1 – CLIMATE