AMUNDSEN-SCOTT SOUTH POLE STATION

by Dr. John Lynch National Science Foundation

November 1994

History

Attainment of the geographic South Pole was a primary concern of early 20th century explorers. Tentative forays into the Antarctic region had been undertaken by several expeditions during the 19th century, but it was not until the early 1900's that the Pole itself was considered to be a realistic goal.

Two British expeditions, the "Discovery" expedition of 1902 and the "Nimrod" expedition of 1908, were the first to depart for the continent with conquest of the Pole an expressed purpose. Robert F. Scott's "Discovery" expedition established an initial "furthest south" record, but competing expedition priorities prevented further progress. In 1908, Ernest Shackleton, a member of Scott's "furthest south" party, returned to the Antarctic as leader of the "Nimrod" expedition. In a remarkable feat of endurance, Shackleton and several others came to within 97 miles of the Pole before returning to their base at McMurdo Sound and an eventual hero's welcome in England. Victory, it seemed, would come to the next expedition.

Such, in fact, proved to be the case, but it came to a Norwegian expedition, led by the ascetic Roald Amundsen. Amundsen, perhaps the ultimate polar technician, had developed an interest in reaching the South Pole concurrent with the formation of Robert Scott's second or "Terra Nova" expedition. When Scott sailed for the Antarctic, Amundsen was not far behind and by intent or coincidence a race began.

The race ended on 14 December 1911, when Amundsen and four others arrived at the South Pole after a generally uneventful and carefully managed overland journey. Their return was equally uneventful. Amundsen's almost lighthearted success contrasted starkly with the fate of the Scott party. Scott and four companions reached the Pole a month after Amundsen, on 17 January 1912. Beset with problems from the outset and mortally weakened by the rigors of the return journey, Scott and his companions perished.

The next visit to South Pole occurred on 29 November 1929 when Richard E. Byrd, Jr. flew over the Pole and threw an American flag and other mementos out the window of his Ford Trimotor airplane.

The Modern Era

The next surface visit was on 31 October 1956. On that date, a ski-equipped R-4D aircraft landed at the Pole. On board were Admiral George Dufek and several other personnel of the United States Navy. Their purpose was to survey the site in preparation for the establishment of a research station, one of many planned for the International Geophysical Year (IGY). Construction of the original South Pole Station began the following month and by February 1957, the station was complete. An eighteen man Navy support and civilian scientific crew, led by John Tuck and Paul Siple remained for the winter, the first of the winter-over parties which have continuously occupied what became known as Amundsen-Scott South Pole Station. It is interesting to note that Admiral R.E. Byrd was by then the director of the U.S. Antarctic Program.

The original station had been modified and expanded over the years, but by 1967 it became increasingly apparent that a new station would be needed. Construction of the new South Pole Station began during the 1970/71 austral summer. Erection of the dome, arches, and interior modules took place over the next three summers. Finishing work was concluded during the 1974/75 season, and in January, 1975, the station was formally dedicated. The old station was abandoned and winter operations commenced at the new facility the following month.

At 20 years of age, the present station is now rapidly reaching the end of its useful life, and NSF is well advanced in planning redevelopment of the station on the current site. The next station will feature extremely well insulated elevated modular structures to reduce fossil fuel usage and snow drifting. Alternative energy sources, such as solar and wind, are expected to be widely used. Several new outlying structures which have been built in the past few years foreshadow the philosophy of future construction.

The South Pole Station is situated at 90 degrees South on the Polar Plateau. The station was originally constructed 400 meters from the geographic South Pole; however, ice movement, at the rate of 10 meters per year, will eventually carry the station over the actual Pole.

The site is at an elevation of approximately 2850 meters (9300 ft) most of which is measured in ice thickness. The very low atmospheric temperatures produce an effective average pressure altitude of approximately 3230 meters (10,600 ft). The mean annual temperature is -49.3 degrees C (-56.7 F). The lowest recorded temperature is -82.8 degrees C (-117.0 F) and the highest temperature is -13.6 C (+7.5 F).

An extremely arid environment limits annual snowfall; however, a relatively constant windspeed of 5-15 knots compounds the accumulation and accounts for the heavy snow drifting common to inland Antarctic stations. The surrounding terrain is completely flat, nearly featureless snow.

Station Facilities

The central area of the station is located beneath an aluminum geodesic dome, 50 meters (165 ft) in diameter at the base and approximately 17 meters high (55 ft) at its apex. The dome houses three two-story structures which contain living, dining, communications, recreation, laboratory, and meeting facilities. The station can accommodate a crew of 28 during the winter period and a crew of up to 28 during the summer in the dome itself, with up to an additional 120 people accommodated in the facility called Summer Camp 150 meters (500 ft) grid southwest of the station. One of the summer camp buildings is a modern, solar heated, dormitory complete with lounge, bathrooms and laundry facilities which was completed during the 1993-94 season.

A series of steel arches runs perpendicular to the axis of the dome's main entryway and houses the garage complex, gymnasium, carpenter shop, power plant, biomedical facility, and main fuel storage. The fuel arch contains nine 25,000 gallon bladders, giving the station a maximum capacity of 950,000 liters or 225,000 gallons of JP-8 fuel. The four story Skylab and the balloon inflation tower adjoining the main station and are accessible through covered archways. The Clean Air Facility for atmospheric chemistry lies 100 meters upwind of the station. Other research modules are located away distances from the station.

Primary station power is provided by one of three 350 kW diesel generators. Waste heat is utilized for station heating via a glycol circulation system that conducts the heated coolant through the various station structures. Another glycol loop supplies heat to the snow melter while yet another heat exchanger uses the exhaust heat to operate a water well melted in the ice sheet. These systems, as well as water, sewage, phone, computer, and electric lines are routed through a series of sub-surface steel utility corridors, called utilidors.

Station Mission

The purpose of the South Pole Station is to provide a year-round facility for scientific projects. Current on-going programs include:

1. Upper Atmospheric Physics, which includes auroral observations, magnetospheric and ionospheric studies, dynamics of the mesosphere and lower thermosphere, and the study of cosmic ray intensity variations which are caused by solar activity. South Pole is one of the best-equipped upper atmosphere observatories on earth, housing 10 entirely different projects, several of which consist of more than one experiment.

2. Astrophysics, which includes solar astronomy, neutrino and gamma-ray astronomy, cosmology, millimeter and sub- millimeter, and infrared astronomy.

3. Meteorology, which provides South Pole weather data for archival and research, as well as flight operations.

4. Atmospheric studies, which include a Clean Air Facility for the monitoring of minor gas species which are important in global climatic change (e.g. ozone and carbon dioxide) and the sampling of airborne particulates. The South Pole Clean Air Facility is one of NOAA's four baseline Clean Air Facilities which are operated by the Climate Monitoring and Diagnostics Laboratory (CMDL). The others are in Alaska, Hawaii, and American Samoa. The site is, of course, central for the studies of the "Antarctic Ozone Hole"; and

5. Solid Earth Geophysics, which includes the measurement of global seismic activity and other seismological phenomena.

In addition to the long-term projects there are numerous shorter-term scientific endeavors which range from anthropology to cosmology. During the 1994-95 austral summer season 33 science and four technical projects will be supported. A few of these projects are:

As part of a larger study of planetary waves in the Antarctic mesosphere, there will be during 1995 a year-long effort to measure the winds near the mesopause at approximately 90 km altitude by using a radar that tracks the drift of the debris of meteors as they burn up entering the atmosphere. The project is a collaboration of Professor Jeffrey Forbes of the University of Colorado and several Russian colleagues from the institute TYPHOON in Moscow. The meteor radar will be installed and operated for an entire year by Dr. Nikolai Makarov of TYPHOON. For many years it was the custom for a US scientist to spend a year at a Soviet Antarctic station and for a Soviet scientist to spend a year at one of our stations. This practice was ended in the early 1980s, but this experiment during the calendar year of 1995 will bring back a small taste of the previous custom.

Another new project which will study the structure of the atmosphere is a powerful lidar (light radar) system from the University of Illinois. The system uses different wavelengths of light to: characterize the polar stratospheric clouds, which play an important role in the ozone hole; measure the temperature profile from 2 to 70 km; observe polar mesospheric clouds; and measure the structure and motion of the sodium layer near 90 km altitude.

The "Center for Astrophysical Research in Antarctica," or CARA, conducts research in the microwave, millimeter, sub- millimeter, and near-infrared. CARA, a National Science Foundation Science and Technology Center, is under the direction of Dr. D.A. Harper of the University of Chicago's Yerkes Observatory. Collaborating institutions include Carnegie-Mellon University, University of Colorado, University of Illinois, Boston University, AT&T Bell Laboratories, Haverford College, Rockwell International, Smithsonian Astrophysical Observatory, University of Arizona, George Williams College, Adler Planetarium. Cooperating foreign institutions include the University of Cologne (Germany), Mt. Stromlo/Siding Springs Observatory and the University of New South Wales (Australia), and the University of Nice (France). This past winter, CARA had its first winter-over crew of three people and the same number will winter in 1995.

This austral summer, members of the CARA project AST/RO (Antarctic Submillimeter Telescope and Remote Observatory) will install their telescope and instrumentation in the AST/RO building, located across the skiway from the main station. This 1.7 m telescope will carry out a spectroscopic survey of neutral carbon emission from dense atomic regions of the interstellar medium throughout the Galaxy, in order to improve understanding of the formation of star-forming clouds. It is substantially impossible to make these observations elsewhere due to atmospheric water vapor. In addition to funding from NSF, substantial support for AST/RO has come from AT&T Bell Labs, Harvard-Smithsonian Center for Astrophysics, Boston University and the University of Cologne in Germany. NASA is providing funds for one of the instruments.

Also located across the skiway is the Martin A. Pomerantz Observatory, which houses the other CARA experiments, as well as the AMANDA (Antarctic Muon and Neutrino Detector array) project. Together these buildings are located in the "Dark Sector," an area of the station which is designated to be kept free of light and radio frequency pollution, to accommodate astrophysics research.

Another CARA project is the Python telescope (one of the COBRA series), which conducts cosmology research by searching for anisotropy in the cosmic microwave background radiation (CMBR). This ongoing experiment moved to the Dark Sector just last year, and finished its first winterover operation. Python is the only telescope which has confirmed its own detection of the CMBR anisotropy in the same patch of sky: measurements made during the austral summer of 1993 were nearly identically duplicated during the summer of 1994. The dryness and extreme stability of the atmosphere are essential for the COBRA experiments.

The third CARA telescope project is the 60 cm South Pole Infrared Explorer (SPIREX), which operates in a uniquely clear and dark atmospheric window at a wavelength of about 2.4 microns. During the winter of 1995, SPIREX will continue its mission of characterizing the site and atmospheric disturbances.

An entirely different field is high energy astrophysics, which makes use of cosmic rays, gamma rays and neutrinos with energies in excess of 1 TeV. There are several projects of this nature at Pole.

Two experiments, GASP (Gamma-Ray Astrophysics at South Pole), and SPASE (South Pole Air Shower Experiment) search for astrophysical gamma-ray sources by using the Earth's atmosphere as a detector, by detecting particle showers at the surface and by observing near-UV and visible Cherenkov radiation. The Bartol Research Institute of the University of Delaware, Leeds University (U.K.), University of Wisconsin, Purdue University, and the Smithsonian Astrophysical Observatory participate in these experiments. Construction of a new version of SPASE will begin this season in the Dark Sector, about 300 m downwind of the observatories there.

AMANDA (Antarctic Muon and Neutrino Detector array) is a collaboration between University Wisconsin, University of California, Berkeley, and University California-Irvine, the University of Stockholm and the University of Upsala (Sweden) which searches for muons produced by neutrinos which have passed completely through the earth. This downward-looking telescope is in reality an array of photomultiplier tubes buried in the ice sheet, up to a kilometer deep. In addition to its principal aim of studying upward going neutrinos, AMANDA is sensitive to extremely high energy muons produced by cosmic rays in the atmosphere above South Pole, and in this mode the AMANDA-SPASE pair form the most sensitive detector for the determination of the composition of high energy cosmic rays. After examining data from the current array, the AMANDA collaboration decided that future photomultipliers need to be buried even deeper in the ice; the drilling component of this experiment has been delayed until the 1995-96 season while a new drill is developed by the Polar Ice Coring Office (PICO). Six more long strings of detectors will then be installed much deeper than the present four strings.

There is a summer-long study of the vibrations of the surface of the sun. Called solar seismology, in analogy to seismological studies which provide insight into the interior of Earth, this work can provide very detailed information on the internal structure of the sun. Very high resolution monochromatic images will be taken whenever the sky is clear enough every 42 seconds for the entire summer. These pictures can then be analyzed to provide very precise frequency information on hundreds of different modes of oscillation of the sun. It is very important that the observations be as continuous as possible, and especially important that they not be interrupted periodically, such as by the rising and setting of the sun. This project is an excellent example of research which takes advantage of the fact that the sun is continuously above the horizon for six months. The work is a joint project of the Bartol Research Institute, the National Solar Observatory and NASA's Goddard Space Flight Center.

Construction projects at Pole this year include an annex to the AST/RO building, which will store liquid helium for use with the AST/RO experiment, the completion of the interior of the Martin A. Pomerantz Observatory, and the erection of a telescope tower for the SPIREX (South Pole Infrared Explorer) experiment. In addition to these science projects, an electrical substation will be built under the dome at the main station.

Current Operations

This year's winterover crew will consist of 27 people (6 women and 21 men); 19 of the personnel will be ASA employees; while the remaining 8 will be employees of grantees or NOAA.

The station is supported and managed by Antarctic Support Associates (ASA). Transportation and other logistical needs are supplied by the Naval Support Force Antarctica (NSFA). Both groups work under contract to the National Science Foundation.