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Hottest
Temperature....
EL AZIZIA, LIBYA
How Hot is Hot?
There are many places
on earth that are plenty hot - record-breaking hot. In fact, there's
a good chance on the day this record-breaking temperature was recorded
by a meteorological station in El Azizia in 1922 there were other
places hundreds of miles away that were even hotter. In all likelihood,
this record temperature has been exceeded since then in many places
on earth, but we have no official records of the temperatures. It
is important to note that when atmospheric temperatures are recorded
it is not the surface temperature, where it can sometimes
reach 150° F/ 66° C, but rather the air temperature
at about 5 feet (1.6 m) above the surface in an enclosed shelter.
Of course, it's important that the temperature sensor is not exposed
to direct sunlight - the shelter is louvered to permit air flow
across the sensor. Most humans don't 'hang out' where some of the
hottest tempertatures on earth are regularly experienced so there
aren't a lot of meterological stations in these places to reliably
record extreme temperatures.
Desert Lands
As big as the earth is,
over two thirds of its surface is covered in water from the oceans.
The remaining one-third of the earth's surface is exposed as dry land
for us to live on, but a third of that dry land is really dry.
In fact, it's inhospitable desert. Much of the deserts in the world
are clustered between 5 to 30 degrees north and south of the equator,
in what are called subtropical zones.
Scientists have theorized that these desert belts are due to two things:
Duh? Anybody who's ever
been outside on a hot summer day, all day, knows that. Just
about every continent on earth that is inhabited by humans experiences
seasonal weather changes, with a distinct winter and summer. Just
because there's hot, dry weather during the summer, doesn't mean that
where you live is going to turn into a desert. What makes the desert
so hot and dry is the climactic conditions that are sustained almost
continually, year round. Any part of the world that's hot and dry
for long enough periods throughout the year won't be able to support
much plant or animal life. Living things need water to survive.
Why is it so Dry All the Time?
First, the air in the earth's
atmosphere is warmest around the equator (because the sun reaches
the earth at a direct 90° angle) so that warmer air rises and
flows north and south of the equator. As the air "piles" up in the
northern and southern latitudes, these zones of "piled-high" warm
air become permanent high pressure zones.
As the air at the "bottom of the pile" descends toward the earth
it gets warmed up even more. Because this descending warm air has
no clouds (i.e., condensing water vapor), that allows the burning
sun to go right through the air and heat the land mass below even
more. Hence, extreme heat.
Where's the coldest
place on earth?
Warm air can hold a lot
more moisture (water vapor) than colder air. Unless this really
warm air contacts some much cooler air (or cooler land mass), there's
nothing to coax the moisture out of the air in the form of precipitation
(rain, fog). Hence, lack of moisture.
What Goes Around, Comes Around
This hot air moves northward
and southward of the equator, almost continuously in the form of
reliable winds called the
Trade Winds. As these warm
winds circulate back around towards the equator they rise into the
upper atmosphere again, cooling. The water vapor in the cooling
air mass condenses and rains, and rains and rains all over the equator
in the Tropical zones. All this
rain makes the land mass around the equator the lushest, wettest,
most densely forested in the world (plants love water!). It's ironic
that the wettest and hottest places in
the world occur within just a few thousand miles of each other.
Though the hottest place
in the world, El Azizia, is a desert, not all deserts are hot. Antarctica,
for example, is the driest continent
on earth, getting less than 4 in/10cm of precipitation a year. What
characterizes or defines a desert is the lack of precipitation -
less than 10 in/25.4cm per year. In the Antarctic, there is very
little precipitation in the form of rain or snow. Even though there's
water, water everywhere it's locked up in the form of ice.
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Location: El Azizia is located
on the northern part of the African continent.
Facts: On September 13,
1922 the thermometer reached a blistering 136° F/57.8°
C.
The Scientists Who Study this Cool
Stuff?
Metereologists, Climatologists, Geologists.
Links:
Hot
Deserts of the World
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Death Valley comes in a close second, at
134° F/ 56.6°C on July 10, 1913.
(Photo: NPS).
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