May 21, 1998
These small trailer-like observatories measure eight-by-eight-by-sixteen feet and provide 50 watts of electrical power to the experiments. They store data to be retrieved later during the Antarctic summer. The AGOs also report on weather and their own status via satellite.
"Antarctica is the only place on earth where there's a landmass to base these instruments to study the upper atmosphere at very high magnetic latitudes -- and at many different magnetic longitudes," said Louis Lanzerotti of Bell Laboratories, Lucent Technologies. Lanzerotti uses the observatories to house magnetometers which measure changes in the earth's magnetic field caused by electrical currents in the upper atmosphere. Naturally changing currents can induce secondary currents in long-distance telephone lines, for example, sometimes causing damage or interference.
"Data from the AGOs, added to observations from the inhabited Antarctic stations and from AGOs of the British Antarctic Survey, are beginning to give us a wealth of information about the ionosphere at high geomagnetic latitudes -- the region around the earth's geomagnetic pole," said John Lynch, National Science Foundation (NSF) program director for polar aeronomy and astrophysics.
"This is where magnetic-field lines and ionized particles come down from space to intersect the earth's atmosphere, so we can study the outer parts of the earth's magnetosphere," Lynch said. "The AGOs are also helping to foster better understanding of the earth's response to solar activity."
Knowing the physics of the magnetosphere helps to predict geomagnetic storms that can disrupt power grids and satellite communications.
The long, dark Antarctic winter permits optical observations of the aurora around the clock. The extremely cold, dry air of the East Antarctic plateau also lends clarity to such observations. These measurements cannot be done at similar latitudes in the north which are located above the Arctic Ocean -- not a stable observing platform. Besides magnetometers, the AGOs contain VLF-HF (very low frequency/high frequency) receivers, riometers, and all-sky cameras.
The AGO network is the result of years of planning how to use stable, earthbound sites to acquire data on the upper atmosphere and space. The network had to overcome the challenge of operating in the harsh environmental extremes of Antarctica.
For further information, including photos of an AGO and a map showing the
AGO network in Antarctica, see:
http://www.polar.umd.edu and
http://sprg.ssl.berkeley.edu/atmos/data/
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