224
H. WALTER AND E. STADELMANN
deserts in Central Australia can be considered as real deserts with regard
to the climate. Rather, these areas are difficult to cross unpopulated sandy
regions without open water places, yet they have considerable vegetation.
The climate of the arid regions on the various continents is not at all
similar. These regions may be classified at first with regard to their temperature ranges:
1. Arid regions of the tropics with very little differences in the average
monthly temperature include the islands of the South Caribbean Sea and
on the north coast of Venezuela; northern part of Somalia; Island of
Sokotra (off the east coast of Africa).
2. Subtropical arid regions with considerable temperature fluctuation
during the year and occasional frost include the Sonora Desert (Northern
Mexico and Southern Arizona); the Mojave Deserts of Southern California; the Sahara-Arabian Desert region, the South Iranian Desert and
the Thar Desert (India), including part of the Sind region (West Pakistan). In the Southern Hemisphere are the Southern Peruvian-Northern
Chilean region, the Namib Desert (Southwest Africa), Karroo region
(South Africa), and the driest regions of Australia.
3. Arid regions of temperate zones which often have very cold winters
include the Great Basin west of the Rocky Mountains (North America),
the transitional regions between the Syrian-Mesopotamian and the Iranian-Turkmenian Desert north of the border line for date palm cultivation,
the Kazakhstanian-Dzungarian (Sinkiang) Desert, the Tarim basin with
the Takla Makan Desert (Sinkiang), Bei-shan (Sinkiang/Inner Mongolia),
the Alay Shan Desert (Inner Mongolia), Ordos Desert (Inner Mongolia)
and the Gobi Desert (Mongolian Republic/Inner Mongolia). In the temperate zone of the Southern Hemisphere the only arid region of this kind
is Patagonia (Argentina).
4. Cold highland deserts are the Puna in the Andes Mountains (South
America), Pamir (Central Asia), and Tibet.
For the vegetation of arid regions, however, the absolute amount of the
monthly rainfall, and especially the seasonal distribution of rainfall, is more
important than the temperature of these areas. Thus, these arid regions
can be classified on the basis of rainfall into the following groups ( 1 ) arid
areas with two rainy seasons: North Venezuela (A), Southwestern
Somalia (B), Sonora Desert (C), Karroo region (South Africa, D); (the
letters here and below refer to the climate diagrams of Figs. 7 and 8, given
as examples for these regions.) ; (2) arid regions with winter rains: Mojave
desert (E), Northern Libya (F), Mesopotamia (G), Northern Chile (H),
Northern Sahara; (3) arid regions with summer rains: Nubian Desert (I),
H. WALTER AND E. STADELMANN
deserts in Central Australia can be considered as real deserts with regard
to the climate. Rather, these areas are difficult to cross unpopulated sandy
regions without open water places, yet they have considerable vegetation.
The climate of the arid regions on the various continents is not at all
similar. These regions may be classified at first with regard to their temperature ranges:
1. Arid regions of the tropics with very little differences in the average
monthly temperature include the islands of the South Caribbean Sea and
on the north coast of Venezuela; northern part of Somalia; Island of
Sokotra (off the east coast of Africa).
2. Subtropical arid regions with considerable temperature fluctuation
during the year and occasional frost include the Sonora Desert (Northern
Mexico and Southern Arizona); the Mojave Deserts of Southern California; the Sahara-Arabian Desert region, the South Iranian Desert and
the Thar Desert (India), including part of the Sind region (West Pakistan). In the Southern Hemisphere are the Southern Peruvian-Northern
Chilean region, the Namib Desert (Southwest Africa), Karroo region
(South Africa), and the driest regions of Australia.
3. Arid regions of temperate zones which often have very cold winters
include the Great Basin west of the Rocky Mountains (North America),
the transitional regions between the Syrian-Mesopotamian and the Iranian-Turkmenian Desert north of the border line for date palm cultivation,
the Kazakhstanian-Dzungarian (Sinkiang) Desert, the Tarim basin with
the Takla Makan Desert (Sinkiang), Bei-shan (Sinkiang/Inner Mongolia),
the Alay Shan Desert (Inner Mongolia), Ordos Desert (Inner Mongolia)
and the Gobi Desert (Mongolian Republic/Inner Mongolia). In the temperate zone of the Southern Hemisphere the only arid region of this kind
is Patagonia (Argentina).
4. Cold highland deserts are the Puna in the Andes Mountains (South
America), Pamir (Central Asia), and Tibet.
For the vegetation of arid regions, however, the absolute amount of the
monthly rainfall, and especially the seasonal distribution of rainfall, is more
important than the temperature of these areas. Thus, these arid regions
can be classified on the basis of rainfall into the following groups ( 1 ) arid
areas with two rainy seasons: North Venezuela (A), Southwestern
Somalia (B), Sonora Desert (C), Karroo region (South Africa, D); (the
letters here and below refer to the climate diagrams of Figs. 7 and 8, given
as examples for these regions.) ; (2) arid regions with winter rains: Mojave
desert (E), Northern Libya (F), Mesopotamia (G), Northern Chile (H),
Northern Sahara; (3) arid regions with summer rains: Nubian Desert (I),