12th November 2015
N e w s a d e m ic .co m ™
- British English edition
page
10
F
l o w e r in g
desert
Many local people and tourists
have been travelling to the Ata
cama Desert. There, they have
been looking at an unusual phe
nomenon. Called a flowering de
sert, it normally occurs once every
five to seven years.
Yet this year,
the Atacama has ‘flowered’ twice.
This has never been known to
happen before.
The Atacama Desert is a high
plateau. It is between two mountain
ranges. The Andes Mountains are
to the
west and the Chilean Coast
Range to the east. These mountain
ranges run parallel to each other.
This creates a ‘double rain shad
ow ’. A rain shadow is a dry area on
one side of a mountain range. The
shadow is on the opposite side to the
one facing oncoming, or prevailing,
winds. Forced to rise by the moun
tains, moisture in the air precipi
tates, or becomes rain. This imme
diately falls. The air that then passes
to the other side of the mountain is
very dry. It is therefore unlikely to
produce any rain.
Atacam a Desert, in Chile (Valerio Pillar)
M ost of the Atacama Desert is in
Chile, although its northern bound
ary is inside Peru.
The desert is one
o f the w orld’s driest places. On av
erage there is about 15 millimetres
(0.6 inches) o f rain per year. How
ever, in some areas of the Atacama
there has been no rain for over four
years. It is not hot like the Sahara
Desert, in Africa. This is because
most o f the plateau is around 4,000
metres (13,100 feet) above sea lev
el. Therefore the Atacama is w hat’s
known as a cold desert.
Many
of the biggest telescopes
(or astronomical observatories) in
the world are in the Atacama De
sert. The Earth’s most powerful
telescope is currently being built on
the top of a Chilean Coast Range
mountain. Called the European Ex
tremely Large Telescope (E-ELT), it
will take ten years to complete. The
Atacama Desert is one o f the w orld’s
best places for telescopes. This is
because it is high, there is very little
moisture in the air, and almost every
day and night is cloudless.
The
flowering desert occurs
when there has been far more rain
fall than usual. It normally happens
between the months of September
and November. The flowering de
sert is connected with w hat’s called
an El Nino, or El Nino event. It’s
known that sea temperatures in the
Pacific
Ocean off the north east
coast o f South America can change
dramatically. W hen this part o f the
Pacific starts to get much warmer, it
is usually a sign of an El Nino. N o
body knows what causes these big
sea temperature
changes in this part
o f the world. On average they occur
every five years. Scientists say that
a strong El Nino is happening now.
An El Nino usually affects the
weather on both sides of the Pa
cific Ocean and in other parts of
the world.
During an El Nino there
is much more rain in the northern
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