International Polar Year 2007–2008 - WMO

July 2007, the first IPY year, an international traverse
team transferred heavy equipment from a previous
Greenland deep drilling site (NGRIP) to the NEEM site.
They undertook radar and GPS surveys and collected
shallow ice cores along the route, and made a detailed
radar survey over a 10-km by 10-km area to locate the
best site for the NEEM core. A seed camp and a skiway
were constructed at the chosen site. In 2008, the living,
drilling and core analysis facilities were established
at the NEEM site (Fig. 2.4-3). Shallow test cores were
collected at the NEEM site in the 2008 season (Fig. 2.4-
4), but it was not till mid May 2009, after the end of
the formal IPY fieldwork and observation period that
the deep ice coring commenced at NEEM. Drilling
continued more or less continuously throughout the
2009 season and by the end of the season in October,
the borehole depth had reached 1758 m. Bedrock
was not finally reached, at 2537 m depth, until 27
July, 2010. The full core contained ice from the warm
interglacial Eemian period, 130,000 to 115,000 years
before present, and even older ice was recovered. The
bottom 2 m of ice contained rocks and other material
that has not seen sunlight for hundreds of thousands
of years, and is expected to be rich in DNA and
pollen that can tell us about the plants that existed in
Greenland before the site became covered with ice,
perhaps as long as 3 million years ago.
Detailed measurements were made on the NEEM
core in a sub-surface science trench as the core was
extracted. State-of-the-art laser instruments for water
isotopes and greenhouse gases, online impurity
measurements and studies of ice crystals are among
the impressive instruments deployed at the NEEM site,
at one of the most inaccessible parts of the Greenland
ice sheet. Full laboratory analysis of the NEEM ice core,
however, has only just commenced.
In September 2007, a survey of the ice sheet was
conducted out of Thule and Sondrestrom from a NASA
P-3B (Orion) aircraft as a part of the NASA Instrument
Incubator Program and as a continuation of NASA
measurements to monitor the Greenland ice sheet.
A 150/450 MHz ice radar system, developed by the
Center for Remote Sensing of Ice Sheets (CReSIS) at the
University of Kansas, was used to conduct this survey,
with six receiving antennas and two transmitting
antennas, which enabled formation of interferometric
SAR images with variable baselines. The project was a
collaborative effort between the Ohio State University,
the Jet Propulsion Laboratory, VEXCEL Inc. and the
University of Kansas, and was aimed at demonstrating
the concept of sounding ice and imaging the ice-bed
interface with orbital radars. The aircraft was flown
at altitudes as high as 6700 m above sea level and as
low as 500 m above the ice sheet surface. Flight lines
were designed to capture surface clutter conditions
across outlet glaciers discharging into the ocean,
down the length of the floating portions of Petermann
and Jakobshavn glaciers, and to cross from the wet
percolation facies of the ice sheet into the dry snow
zone. A flight extending from Camp Century to Dye-2
passing over the NEEM, NGRIP, GISP-2, GRIP and DYE-
2 ice-core sites was also conducted with the primary
objective of connecting all the deep ice cores with the
radar operating at 150 MHz. The 2007 flight lines are
shown in Fig. 2.4-5.
Fig. 2.4-5. Greenland
aerial radar survey
lines in 2007 (IPY no.
118). The red central
flight line, extending
from Camp Century
to Dye-2, was flown to
obtain radar data to
connect ice cores.
(Courtesy: Center for Remote
Sensing of Ice Sheets, U.
Kansas)
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