April 19, 2007
SCIENTISTS
AND POLAR
EXPLORERS BRAVE THE ELEMENTS IN SUPPORT OF CRYOSAT-2
It is perhaps
an unlikely combination – an international
team of scientists stationed in Svalbard, Norway
and two
polar explorers crossing the North Pole on foot. Both teams, however,
are currently
part of a common effort to collect vital data on the ground and from
the air in
support of ESA's ice mission CryoSat-2.
The CryoSat-2 mission, due for launch in 2009, will provide highly
accurate
information on changing marine and land ice thicknesses over the entire
north
and south polar regions, and in doing so will help address key
questions
regarding the impact of climate change on the polar environment. The
mission is
a technical tour-de-force if you take a step back and consider that the
satellite
will be traveling at over 25,000 kilometers per hour at 717 kilometers
above
the surface of the Earth and yet still measure changes in the ice
thickness
down to a few centimeters per year using its sophisticated radar
altimeter
SIRAL. Given these objectives and the importance of accurate
measurements in
assessing environmental change, it is not surprising that ESA goes to
great
lengths to ensure that the data from CryoSat-2 will be as accurate as
possible.
Enter the Arctic Arc Expedition, part of the International
Polar Year. The expedition’s two Belgian explorers, Alain
Hubert and Dixie
Dansercoer, 'stepped' onto the sea ice off the coast of Siberia on the
1 March
2007 and have so far covered a staggering 2,500 km each pulling a
130-kg sledge
holding supplies and equipment. Along the way these two intrepid
explorers are
contributing to the preparation of the CryoSat-2 mission by measuring
snow
depths at regular intervals. These data in turn will be used by
scientists to
assess how well snow conditions can be predicted using existing climate
models
as well as inputs to methods for improving the accuracy of CryoSat-2
maps of
sea-ice thickness.
"We are making
good progress," said Alain Hubert
when contacted in his tent on the ice with his satellite phone a few
days ago.
"We are now only 160 km from the North Pole and taking snow-thickness
measurements at regular intervals along the way. Sometimes conditions
are very
difficult because of the cold and wind. However, we feel the effort is
worthwhile and we will keep going."
As Alain and
Dixie trek across the North Pole, a parallel
campaign by scientists from Germany,
Norway
and the UK
is unfolding in the extreme northern
archipelago of Svalbard,
Norway.
On Thursday12 April, a
group of eight scientists were transported by helicopter to the remote
Austfonna ice cap. As part of the CryoVex 2007 campaign, they will
spend one
month making measurements of snow and ice properties along long
transects that
criss-cross the ice sheet surface. Conditions on the ground are often
difficult, with high winds and low temperatures. The result is that
sometimes
the instruments and equipment fail as the leader of the ground team,
Jon Ove
Hagen from the University of Oslo,
pointed out.
"We are
currently moving our team from the depot at the
bottom of the Austfonna ice cap to the summit so that we can start our
ground
measurements and support the airborne acquisition," said Jon Ove Hagen
when contacted on Monday 16 April. "Bad weather and a broken skidoo are
simply things we need to work around as we start our measurement
programme."
As the ground
experiments are carried out, measurements are
also being taken from the air by the Alfred Wegner Institute (AWI). The
Dornier-228 aircraft carries the ASIRAS instrument, which is an
airborne
version of the radar altimeter instrument onboard CryoSat-2. By
comparing the
airborne data with ground measurements scientists will test and verify
novel
methods for retrieving ice-thickness change from the CryoSat-2
satellite
mission ahead of the launch.
"The first
flight with ASIRAS looks good," says
Veit Helm from AWI. "As soon as the weather conditions are good and the
ground teams are in place, we look forward to our scientific flights
and
getting our hands dirty processing and analyzing the airborne radar
altimeter
data over Austfonna. One fascinating aspect of such work is that the
campaign
actually allows us to look into the future and see what the CryoSat-2
mission
will see and measure when it is launched."
The airborne work will continue until 24 April and
the ground teams will stay on the ice cap until the beginning of May.
When the
campaign draws to an end, the challenge will then be to analyze the
large
volumes of data in order to characterize and improve the CryoSat-2
measurements
of changing ice surfaces. In is only through such painstaking work that
the
challenge of measuring ice thickness down to centimeter level from
space can be
achieved, and in turn lead to a better understanding of the impact that
changing climate is having on the polar ice fields.
##
Contact:
Mariangela
D'Acunto
European Space Agency
39-069-418-0856
mariangela.dacunto@esa.int
This text derived from:
http://www.esa.int/esaLP/SEMHIYLJC0F_LPcryosat_0.html
Recommend this Article to a Friend
Back to: News |
