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WEEKLY NEWSLETTER
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Mauritania
Index
The Saharan Zone makes up the northern two-thirds of the
country. Its southern boundary corresponds to the isohyet (a line
on the earth's surface along which the rainfall is the same) that
represents annual precipitation of 150 millimeters. Rain usually
falls during the hivernage, which lasts from July to
September. Often, isolated storms drop large amounts of water in
short periods of time. A year, or even several years, may pass
without any rain in some locations.
Diurnal variations in temperature in the Saharan Zone may be
extreme, although annual variations are minimal. During December
and January, temperatures range from an early morning low of
0°C
to a midafternoon high of 38°C. During May, June, and July,
temperatures range from 16°C in the morning to more than
49°C by
afternoon. Throughout the year, the harmattan often causes
blinding sandstorms.
The administrative regions (formerly called cercles)
of Tiris Zemmour in the north, Adrar in the center, and northern
Hodh ech Chargui in the east, which make up most of the Saharan
Zone, are vast empty stretches of dunes alternating with granite
outcroppings. After a rain, or in the presence of a well, these
outcroppings may support vegetation. In the populated Adrar and
Tagant plateaus, springs and wells provide water for pasturage
and some agriculture. In the western portion of the Saharan Zone,
extending toward Nouakchott, rows of sand dunes are aligned from
northeast to southwest in ridges from two to twenty kilometers
wide. Between these ridges are depressions filled with limestone
and clayey sand capable of supporting vegetation after a rain.
Dunes in the far north shift with the wind more than those in the
south.
The Saharan Zone has little vegetation. Some mountainous
areas with a water source support small-leafed and spiny plants
and scrub grasses suitable for camels. Because seeds of desert
plants can remain dormant for many years, dunes often sprout
sparse vegetation after a rain. In depressions between dunes,
where the water is nearer the surface, some flora--including
acacias, soapberry trees, capers, and swallowwort--may be found.
Saline areas have a particular kind of vegetation, mainly
chenopods, which are adapted to high salt concentrations in the
soil. Cultivation is limited to oases, where date palms are used
to shade other crops from the sun.
Data as of June 1988
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