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Building monitoring facilities in the coldest, driest and windiest continent on Earth: by Denise Brettschneider

J o u r n e y t h r o u g H t h e i c e t o pa lm e r S tat i o n , A n ta r c t i c a .

“It was the darkness that did it. I don’t minus 37 degrees Celsius. And although Unsurprisingly, Antarctica has never had believe minus seventy temperatures would Antarctica has more fresh water than any an indigenous population of humans. Yet its be bad in daylight, not comparatively other continent, it also receives the least importance as a natural reserve is recognized bad, when you could see where you were precipitation, with only slightly more internationally. Approximately 30 nations, all going...” In The Worst Journey in the World: rainfall on average than the Sahara Desert. signatory to the 1961 Antarctic Treaty, send A Tale of Loss and Courage in Antarctica, personnel every year to perform seasonal Apsley Cherry-Garrard describes the last Its reputation as the windiest and and year-round research on the continent and expedition to the Antarctic by the explorer, least hospitable continent on Earth is in its surrounding oceans. The population Robert Scott, and his team in 1910. well-deserved. Strong katabatic winds of scientists varies from approximately caused by the drainage of cold air down 4,000 in summer to 1,000 in winter. Total darkness for six the steep slopes of the sheet from months a year the higher interior of the continent, have Hostile environment and been measured at over 250 km/h. These logistical challenges The long periods of constant darkness during winds sometimes ravage the continent for the winter contrast starkly with the summer several days. Blizzards are another typical In order to provide uniform coverage of months in Antarctica, when it is light for Antarctic phenomenon which can last for the globe, the Preparatory Commission almost 24 hours a day. Renowned for having a week at a time, reducing visibility to a for the Comprehensive Nuclear-Test-Ban the harshest and most extreme environment on few feet. Whiteouts, in which there are Treaty Organization (CTBTO) has already earth, the world’s lowest temperature of minus no shadows or contrasts between objects established several of its monitoring 89 degrees Celsius was recorded in 1983 at causing a loss of depth perception, are facilities in remote areas that are difficult the Russian (former Soviet) Vostok research also commonplace. Explorers have been to access. These facilities are part of station in the centre of . The known to get lost and freeze to death the International Monitoring System mean annual temperature of the interior is while only metres away from their tents. (IMS) and include a number of stations

pa g e 1 8 c t b t o S p e c t r u M 1 1 | S e p t e m b e r 2 0 0 8 in Antarctica: eight seismic, infrasound and radionuclide stations have already been certified by the CTBTO as meeting defined requirements and specifications and another five stations are planned.

The IMS comprises a global network of stations and laboratories that monitor the Earth for evidence of a nuclear explosion in compliance with the provisions of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which bans all nuclear explosions on the planet.

As well as contending with an extremely hostile environment when constructing stations in Antarctica, the CTBTO is also confronted with logistical and engineering challenges: the transportation of installation equipment needs to be meticulously planned and coordinated and stations must be specially designed in order to withstand polar conditions.

There are no developed ports on the continent and only a few locations have a D i g g i n g o u t t h e w i n D n o i s e r e d u c i n g p i p e a r r ay a n D e q u i p m e n t Va u lt S at i S 5 5 . p H o t o c o u rt e S Y o F D u n c a n M a r r i o t t, g e o p hys i c a L i n s t i t u t e , u n i v e r s i t y o F a L a sk a , Fa i r b a n ks . basic wharf facility. Most coastal stations have offshore anchorages, and supplies are Buried in snow Windless Bight was chosen as transferred by boats, barges and helicopters. a location since, as the name implies, Satellite communication is extremely difficult Windless Bight is a desolate ice plain there are virtually no surface winds there due to the high latitudes — Antarctica is the devoid of any vegetation, where in contrast to the rest of Antarctica. In highest continent in the world, with an average temperatures plummet to below minus 40 addition, the infrastructure of the Antarctic height of 2,400 m above sea level —–and it is degrees Celsius. Infrasound station IS55 base that already existed provided crucial only possible from certain research facilities. is part of the IMS and uses very sensitive support for the establishment of the station. microbarometers to detect low frequency The site is powered by a hybrid sound waves which are diesel/solar power supply to ensure inaudible to humans. continuous operations and uses the United These waves can States National Science Foundation’s travel thousands of (NSF) communication system (which funds kilometres and are and manages the United States Antarctic produced by a variety of Programme) to transmit data to Denver, natural and man-made Colorado. The data are then transmitted sources, including via the CTBT’s Global Communications nuclear explosions. The Infrastructure (GCI) to the International latter events have an Data Centre (IDC) in Vienna, where identifiable signature they are processed to detect, locate which distinguishes and analyse events. The raw data and them from other types analyzed data, so-called IDC products, S e a i c e a n D S t o r M S c a n S L o w t h e J o u r n e Y D o w n . of infrasound sources. are transmitted to Member States.

c t b t o S p e c t r u M 1 1 | S e p t e m b e r 2 0 0 8 Pa g e 1 9 Verification highlights

filled by satellites belonging to the Iridium network. The Iridium network is a commercial constellation of 66 communication satellites that circle the Earth on pole-to-pole orbits at a height of 780 kilometres. The Iridium network is unique in that it covers the whole Earth, providing communication coverage at the poles from where other satellites are not visible. The CTBTO has collaborated closely with the USGS to develop this service, which has been heralded as a breakthrough in satellite communication technology. Using this network and with the support and assistance of USGS and NSF, AS114 has been able to transmit important seismic data from the via Denver to the IDC on a 24-hour basis without interruptions since February 2007.

To facilitate operations, the IMS has provided AS114 with a special station interface computer so that it can respond to automatic data requests from the IDC. Shipping supplies and personnel to palmer station Photo Courtesy of NSF/USAP by David Bresnahan, National Science Foundation. Despite the remoteness of the station and the climatic extremes, AS114 has now Windless Bight receives about 1.5 render such opportunities extremely been fully integrated into the IMS. metres of snow accumulation every year. The challenging. The North and South equipment vaults where the microbarometers Poles are the only places on Earth 1,400 km sea voyage from are located must, therefore, be dug out every that cannot see geosynchronous to season and replaced on top of the snow. communication satellites because Infrasound waves can generally penetrate of the distance from the Equator. Radionuclide monitoring station RN73 is the snow for several centimetres with little located at the United States owned Palmer attenuation (in the presence of attenuation, In conjunction with the United States Station on a protected harbour on the south the signal becomes weaker over distance, Geological Survey (USGS), the IMS operates western coast of Anvers Island off the i.e. with smaller amplitudes), but when the an auxiliary seismic station at the South Pole Antarctica Peninsula. The station has been layer of snow becomes too thick, the risk of – AS114. This station provides attenuation becomes higher. It is therefore data on seismic events to the also necessary to dig the wind noise reducing IDC to supplement information system, which is connected to the equipment gathered by primary seismic vaults, out of the snow every year during stations. By the time the the annual maintenance of the station. IMS has been completed, a total of 120 auxiliary seismic Communicating with the stations will have been southernmost point on the certified by the CTBTO. surface of the Earth The issue of no satellite While the Earth’s Polar Regions offer coverage for up to 12 hours unique scientific research possibilities, a day needed to be addressed their isolation and extreme climates and the gap has now been c t b t o ’ S c o mm u n i c at i o n o ff i c e r o u t s i d e a S 11 4 at t h e S o u t H p o l e .

pa g e 2 0 c t b t o S p e c t r u M 1 1 | S e p t e m b e r 2 0 0 8 Re-attaching wind noise reduction pipe array to vault At IS55. Photo courtesy of Duncan Marriott, Geophysical Institute, University of Alaska, Fairbanks.

built on solid rock and consists of two major observation of aerosol samples of solid The radionuclide station is operated by buildings and three smaller ones, one of radionuclides or radionuclide particles. General Dynamics - Advance Information which accommodates station RN73, as well The station contains a Radionuclide Systems (GD-AIS), with the local support of the as two large fuel tanks, a helicopter pad, Aerosol Sampler Analyser (RASA), NSF. The station is unmanned most of the time and a dock. Palmer Station can occupy a which is a fully integrated and automatic with a local operator visiting the station at least maximum of 46 people and is staffed all system for monitoring airborne once every two weeks to perform a physical year round, although the population during radionuclides. The meteorological security and operational check on the RASA. the winter months is usually about 15. system is located on a mast on the roof of the building and is connected to the Complete global coverage Delivering supplies to stations in RASA computer. It includes sensors Antarctica requires careful planning and to measure temperature, barometric The extreme geographical and climatic access to specially constructed vessels. The pressure, humidity, precipitation, wind conditions in Antarctica mean that installing and Research Vessel R/V Laurence M. Gould, a speed and wind velocity. The RASA maintaining monitoring stations is a costly and ship with an ice-strengthened hull designed software controls the station equipment complicated exercise. By establishing stations for year-round polar operations, supports and gathers information about the in such places, the IMS network provides research in the region airflow, air sampler temperature and complete global coverage, thereby acting as a by transporting supplies, researchers and pressure etc. and meteorological data. powerful deterrent to potential violators. ■ staff between Punta Arenas in and Palmer Station. The 1,400 km journey takes As with IS55 and AS114, this Denise Brettschneider is working as a approximately four days, although information is sent through the NSF’s writer and editor with the CTBTO’s Public and storms can slow the journey down. communication system from Palmer Station Information section. She has a number of to Denver and from there to the IDC via years of editorial experience working for RN73 is part of a network of 80 the GCI. RN73 has been transmitting data organizations in Kenya including the United radionuclide monitoring stations that via the United States to the IDC every Nations Educational, Scientific and Cultural enables the continuous worldwide two hours since November 2005. Organization. ■

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