NSF PR 97-52 - September 9, 1997
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Pioneering Team Spending Winter Atop Greenland Ice
Sheet
Winter has already begun for a crew of four who will
spend the entire season atop the Greenland ice sheet
studying the weather at a remote outpost called Summit.
The camp at the apex of the ice sheet, where the sun
will set in November and not reappear until late January,
is the first attempt supported by the National Science
Foundation to over-winter in Greenland.
"This is the first time we will be able to examine
the entire annual cycle of air and snow chemistry,"
said Mike Ledbetter, program manager for Arctic system
science at NSF. "Ultimately, it will help us to better
interpret climate history and how human beings are
affecting climate."
If the project goes well, NSF may explore establishing
a permanent year-round camp at Summit. Up to now,
winter at Summit has been like the dark side of the
moon for scientists, who have not been able to stay
on the scene to study the snowfall in the winter.
They do not even know when most of the snow falls.
The structures and airplane skiway that comprise the
station at Summit cluster atop a broad swell of ice
cap almost two miles thick, 481 miles from its supply
point on Greenland's west coast. NSF extracted the
Northern Hemisphere's longest ice core at Summit from
1989-1993. The core drilled by researchers with The
Greenland Ice Sheet Project 2, along with another
core drilled nearby by European scientists, furnish
an icy archive of over 100,000 years of climate information.
The annual layers in the ice cores store a finely
detailed atmospheric record, as well as traces of
volcanic eruptions, forest fires, ocean storms, atomic
bombs and pollution.
"The falling snow, which eventually becomes compacted
into ice, stores information about the atmosphere
at the time it fell -- the water vapor, temperature
and dust content," said Jack Dibb, the University
of New Hampshire climatologist who heads the wintering
project. "The Greenland ice cores have already shown
us that there were unexpectedly rapid and dramatic
shifts in climate. How closely do these changes in
ice composition actually record the changing chemistry
of the atmosphere? The idea is to turn these records
into a history of the atmosphere's composition."
Dibb's project this year will assist this translation.
"Our goal during this first year-round occupation
of Summit will be to determine what controls the composition
of air just above the ice sheet, to see how closely
the composition of snow reflects that of the air,
and to understand how air and snow exchange water,
energy and chemical compounds through the winter,"
Dibb said.
The wintering crew--an electronics technician, a mechanic,
and two science technicians--will spend most of their
time at Summit in "The Greenhouse," a one-story, 32-by-36
foot building serving as combined bunkroom, living
room, and laboratory. The structure rests on skis
and can be moved from year to year to avoid burial
by snow. The winter-overs will have electronic mail
but not telephone contact with the outside world.
A supply flight in November will rotate one crew member,
with another such flight in February. The University
of Nebraska's Polar Ice Coring Office provides logistics
for the effort.
Winter temperatures at Summit can drop to -60 Fahrenheit
or lower, hampering attempts at winter research with
automated instruments in the past. This winter, however,
the station's crew will be on hand if something goes
awry.
If this winter's experiment goes well, NSF will explore
setting up year-round quarters at Summit for a wider
range of studies in future years, possibly with international
partners. This spring, at a workshop in Greenland
sponsored by NSF and the Danish Research Commission,
scientists from four countries explored the potential
to use a year-round station at Summit to study snow
deposition, atmospheric chemistry, the ozone hole,
magnetospheric physics, and other disciplines.
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