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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 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.
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.
- 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.
- 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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