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 Antarctica
has become a base for collecting meteorological data, including
information on the presence and effects of moisture, carbon dioxide,
and electrified particles on the atmosphere, and the general circulation
of the atmosphere. Antarctica is also important for its great influence
on the world's climate; therefore, meteorological observations are
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Polar Opposites
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The Antarctic continent is named for "opposite
of the Arctic" and is literally in many ways quite different
from its northern counterpart. The Arctic consists of the
ice-covered Arctic Ocean surrounded by many islands and the
northern fringes of the Asian and North American continents.
On the other hand, Antarctica is a high, ice-covered land
mass surrounded by the southern extensions of the Atlantic,
Pacific, and Indian Oceans. As a result of these differences,
the climates of the two regions are very different.
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being made of seasonal
temperatures, atmospheric pressure, wind speed and direction, solar
radiation, and precipitation and evaporation. The studies are made
by atmospheric scientists stationed at scattered points across the
continent. But stations were not located on the basis of where it
would be useful to collect meteorological data, and for a long time
there were significant gaps in the data maps for Antarctic weather.
Now, however, more and more automatic weather stations are being
installed in key positions across the continent. The majority of
these stations belong to the US, but they are sited and maintained
by the cooperative efforts of several other nations.
More solar radiation reaches the surface
at the South Pole than is received at the equator in an equivalent
period.
Total annual radiation at the South Pole
is about equal to that received in equatorial regions, despite
there being 6 months of "night."
This is largely explained by the continent's
high elevation, and its thin atmosphere, and by the air's
unusual clarity.
Most of this heat is reflected back into
the atmosphere by the snow-covered ice sheet and the greater
expanse of sea ice.
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The countries surrounding
Antarctica and the Southern Ocean take a direct interest in the
meteorology of Antarctica. The constantly circling weather systems
drive storms across the Southern Ocean and beyond, while the seasonal
formation and melting of sea ice has a major effect on Southern
Hemisphere weather. Since before the International
Geophysical Year of 1957-58, all Antarctic stations have tried
to collect daily meteorological observations and broadcast them
to surrounding countries to help in weather forecasting.
In addition to
the forecasting efforts in progress, the weather and atmospheric
conditions at the Pole during the austral summer provide unusual
opportunities for studying related solar phenomena.  Certain
gases in the atmosphere--the amounts of nitrogen and oxygen--have
also been studied. Both
contribute to the "greenhouse effect"
and possibly are significant to the Earth's radiative equilibrium
and other interactive effects of ozone
and oxygen: small concentrations of nitrogen may produce large changes
in ozone by conversion to molecular oxygen.
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How much
does it snow in Antarctica?
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Precipitation, nearly all as snow, occurs
frequently over much of Antarctica, but is light.
The total fall varies considerably from
year to year. The scantiness of the snowfall is evident on
the polar plateau, where over large areas annual amounts are
less than 3 centimeters (water-equivalent).
Annual snow accumulation on Ross Island
averages 17.6 centimeters in water equivalent, but accumulation
over the polar plateau to the west of the Dry Valleys is considerably
less.
Within the Dry Valleys most of the snowfall
is associated with humid easterly winds blowing off the Ross
Sea.
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