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1.
Why is Antarctica so cold?
Antarctica
is synonymous with cold, thanks to its polar location,
its high elevation, its lack of a protective, water-vapor
filled atmosphere, and its permanent ice cover which
reflects about 80% of the sun's radiation back into
space. The South Pole is located within a permanent
polar high
created by the normal Hadley Circulation. This creates
an extremely cold air mass which descends at the poles
of the Earth. Unlike the Arctic region, Antarctica is
a continent surrounded by an ocean which means that
interior areas do not benefit from the moderating influence
of water. During the winter, the size of Antarctica
doubles as the surrounding sea water freezes blocking
heat from the warmer surrounding ocean water.
2.
What is the Aurora Australis?
The Aurora Australis or Southern Lights are mesmerizing,
dynamic displays of light that appear in the Antarctic
night skies. They appear in many forms -- pillars, streaks,
wisps, haloes, and curtains of vibrating color. Auroras
are caused by collisions between electrically charged
particles from the sun and gases in Earth's upper atmosphere.
These collisions produce electrical discharges which
energize atoms of oxygen and nitrogen causing the release
of various colors of light.
3.
What is a katabatic wind?
Katabatic
winds occur where cold, heavy air flows down the slopes
of the inland mountains and the ice plateau. This is
a frequent phenomenon as the continent is dome-shaped
and the interior is very cold. As a surface flow, these
winds may be smooth and low in velocity, but there are
many times when they become exceedingly turbulent, sweeping
up any loose snow in their path. This fierce, turbulent
air may suddenly just appear and produce localized Antarctic
blizzards, where the skies are still clear and no snow
actually falls to the ground.
4.
What is a "mock sun"?
"Mock
sun" (also "sun dogs") is a colloquial
term for a phenomenon called "parhelion" which
occurs fairly commonly in polar atmospheres. It is a
false image of the sun, created by the bending of rays
of sunlight within crystals of ice in the atmosphere.
Parhelia are usually observed in pairs, one on each
side of the sun and at the same elevation. They tend
to be red-coloured on the side nearest the sun. Parhelia
are quite close to the sun when the sun is close to
the horizon, but move further away as the angle above
the horizon increases.
5.
Why is the air so dry in Antarctica?
Cold
air holds less moisture than temperate air. This is
because the molecules of air are packed so tightly that
it's as if the moisture has been squeezed out of it.
This means that the air in Antarctica is very dry. Relative
humidities in the interior average less one tenth of
one percent! Most visitors to Antarctica pack a few
extra bottles of moisturizer before setting foot on
the continent!
6.
Does it snow at the pole?
The
South Pole is located within a permanent polar high,
making it possibly the most consistently cloudless place
on Earth where there is a scientific station. Although
there is lots of snow and ice around, the Pole is really
a desert environment, because it averages less than
1 inch of precipitation yearly, about the same as the
Sahara Desert. When warm moist air does make it all
the way to the Polar Plateau, the air cools and becomes
supersaturated with ice crystals. Ice crystals account
for 90% of the accumulation on the plateau.
7.
What
is a temperature inversion?
A
common feature of the polar plateau is a temperature
inversion. A temperature inversion occurs when the coldest
temperatures occur at the Earth's surface, and warmer
temperatures are some distance above the surface (normally,
temperature decreases with height). The temperature
inversion may be only 330 feet (100 meters) thick, but
the temperature difference can be 54°F (30°C)
in that 330 feet! The intensity of inversions is related
to altitude and latitude, and is greater in the winter.
Strong winds, cloud cover, or precipitation can destroy
inversions. Inversions are an important generator of
wind across the continental interior.
8.
What is the Antarctic Convergence?
This
is the region of the Southern Ocean encircling Antarctica,
roughly around latitude 55 degrees South but deviating
from this in places, where the cold waters of the Antarctic
Circumpolar Current meet and mingle with warmer waters
to the north. This mingling creates local variations
in weather, such as fogs, and also a concentration of
marine plants and animals because of its higher than
average nutrients.
9.
Is it windy at the South Pole?
Many
people think of Antarctica as a windy place. That is
true, but only near the edges of the continent. High
on the plateau, at the South Pole, the average wind
speed is typically less than 10 miles per hour, with
the peak winds rarely over 25 miles per hour. Cold,
dense air tends to settle at the Pole making for relatively
calm and clear, yet frigid conditions.
10.
What's
the difference between whiteouts & blizzards?
Blizzards:
Blizzards
are a typical Antarctic phenomenon in which very little,
if any, snow actually falls. Instead the snow
is picked up and blown along the surface by the wind,
resulting in blinding conditions in which objects less
than a meter away may be invisible.
Whiteouts:
Whiteouts are another peculiar Antarctica condition,
in which there are no shadows or contrasts between objects.
A uniformly grey or white sky over a snow-covered surface
can yield these whiteouts, which cause a loss of depth
perception -- for both humans and wildlife.
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