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Zaire
Zaire
AUGUST -
OCTOBER
NOVEMBER -
JANUARY
10°
10°
Angola
Angola
Zambia
Zambia
Zimbabwe
Zimbabwe
20°
20°
Botswana
Botswana
Namibia
Namibia
Inactive
Crest
Flank
Inter-dune
Inactive
Crest
Flank
Inter-dune
30°S
South Africa
30°S
South Africa
0
500
0
500
Km
Km
20°E
30°
40°
20°E
30°
40°
Zaire
Zaire
FEBRUARY
- APRIL
MAY -
JULY
10°
10°
Angola
Angola
Zambia
Zambia
Zimbabwe
Zimbabwe
20°
20°
Botswana
Botswana
Namibia
Namibia
Inactive
Crest
Flank
Inter-dune
Inactive
Crest
Flank
Inter-dune
30°S
South Africa
30°S
South Africa
0
500
0
500
Km
Km
20°E
30°
40°
20°E
30°E
40°E
Figure 24.4 Trimonthly dune system activity status in the Kalahari, southern Africa, averaged for the period 2070-2099. The
shaded area is the Kalahari Sand Sea, currently largely stable and dominated by linear dunes, with shading differences suggesting
the degree of dune landscape activity through the seasons. 'Interdune' implies aeolian activity through the whole dune landscape,
'flank' refers to activity on dune slopes and 'crests' refers to activity on dune crestal areas alone (based on Thomas, Knight and
Wiggs, 2005).
In a similarly posed study of the drylands of China,
Wang et al. (2009) used Lancaster's dune mobility index
(Lancaster, 1988) driven by two climate models (from
an initial selection of five) and a range of emission sce-
narios to determine twenty-first century trends. Defining
predicted by the GCMs are higher than values from 1960
to 1990, Wang et al. (2009) show considerable change
over China. From 2040 to 2099, results from both mod-
els indicate an increase in western arid and semi-arid
China. After 2070, the increases are classed as severe.
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