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The National
Science Foundation Office of Polar Programs Automatic Weather
Station project places automatic weather station (AWS) units in
remote areas of Antarctica in support of meteorological research
and operations. The AWS data are collected by the ARGOS Data
Collection System (DCS) on board the National Oceanic and
Atmospheric Administration (NOAA) series of polar-orbiting
satellites.
The Antarctic continent is 97% covered with ice with an average
elevation of 2300 meters and an average annual temperature of -35
degrees C, making Antarctica the highest and coldest continent on
Earth. Maintaining occupied sites for collecting meteorological
observations is expensive, and the locations may not be
appropriate for the collection of meaningful meteorological data.
The capabilities of an automatic weather station allow for the
retrieval of important weather information without having to have
a person on duty at each site. These stations have proven to be an
invaluable resource for researchers, forecasters, as well as the
general public, as they yield gathering important meteorological
information about the Antarctic.
The AWS units are
placed for meteorological experiments and for operational
purposes. Any one AWS may contribute to several experiments and
all contribute to operational reasons. The units help prepare
weather forecasts for aircraft flights to and from New Zealand and
within Antarctica. Some areas of support are:
a. The Ross Ice Shelf Air Stream
b. Barrier wind flow along the Antarctic Peninsula and the
Trans-Antarctic Mountains
c. Katabatic wind flow down Reeves Glacier, Byrd Glacier,
Beardmore Glacier, and the slope to the Adeile Coast
d. Mesoscale circulation and the sensible and latent heat fluxes
on the Ross Ice Shelf
e. Climatology of Byrd and Dome C Stations
f. Boundary layer meteorology around the South Pole
g. Research in Antarctic Coastal Ecosystem Rates along the
Antarctic Peninsula
h. Long Term Ecological Research along the Antarctic Peninsula
i. Meteorological support for flight operations at McMurdo
Station, Antarctica
j. Monitoring for possible manned station locations and
aircraft landing sites
Figure 1. Antarctic Automated Weather Station at Willie Field
Figure1 shows the AWS unit at Willie Field near McMurdo, Antarctica.
Paroscientific pressure instruments are integrated into AWS by University
of Wisconsin
technicians. There is a custom-made small computer that operates
our AWS. The AWS in the photo has an operational temperature range
of -50 deg C to 5 deg C. Units such as Clean Air and Dome Fuji
have an operational temperature range of-85 deg C to -10 deg C.
The lowest temperature observed on Earth is at Vostok station;
our Dome C unit also recorded a temperature close to the Vostok
temperature. As we have AWS units all over
Antarctica at various elevations, the operational temperature range
varies greatly, but the above temperature ranges illustrate the temperature extremes. Some of the AWS units in the Antarctic
Peninsula region get slightly warmer temperatures. We measure the
gauge temperature so that we can make the required temperature
correction.
Figure 2. Antarctic Automated
Weather Station Map
The University of Wisconsin
Antarctic automatic weather stations program has been
installing automatic weather stations in Antarctica and Greenland
since 1980. After initial tests the Paroscientific Digiquartz
pressure gauge Model 215A was selected for use in our weather
stations. The initial four gauges are still in operation and at
present we have 60 gauges. There are about 600 gauge-years of
operation in the extreme environments of Antarctica and Greenland.
The gauges have operated reliably at gauge temperatures as low as
-80 Deg C. The oldest gauges have drifted about 2 millibars in 20
years. There were failures in our weather stations, but only one
gauge failure. Meanwhile, other sensors like wind speed, wind direction,
air temperature and relative humidity sensors have failed more
often. The gauges are sufficiently accurate to calculate the
horizontal pressure gradient force over distances of 100 km.
At the end of the 2003-2004 field season, just under sixty
stations were operational in the Antarctic. Three new sites,
Wanderer, Vito, and Emilie, were added during the 2003-2004 field
season.
The AWS unit is powered by six to twelve 40 ampere-hour 12 volt
gel-cell batteries charged by one or two 10 Watt solar panels. At
the South Pole, 12 batteries and two solar panels are sufficient
to operate the AWS unit through the year, while six batteries and
one solar panel are adequate on the Ross Ice Shelf. Several of the
AWS units have operated on the same batteries and solar panel for
6 to 10 years.
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