Arctic explorer delivers unique snow-depth data for CryoSat (Forwarded)

ESA News
http://www.esa.int

23 May 2008

Arctic explorer delivers unique snow-depth data for CryoSat

Following a formidable 106-day trek across the Arctic, which ended with the
two Arctic Arc expedition members relying on Envisat images to guide them
safely through disintegrating sea-ice, intrepid polar explorer Alain Hubert
recently visited ESA to handover a unique set of snow-depth measurements.

To coincide with the launch of the International Polar Year (IPY) 2007-2008,
Alain Hubert and fellow explorer Dixie Dansercoer ventured out onto the
sea-ice to embark upon a trek from Siberia to northern Greenland via the
North Pole -- a route never before attempted. Throughout the expedition, the
polar explorers had to endure temperatures down to -40 C, encounters with
polar bears and the incredible physical demand of having to drag heavy
sledges across pressure ridges of sea-ice piled up several metres high as
well as cross open water where the ice had fractured. Nevertheless, Alain
and Dixie took time out every 50 km to make snow-depth measurements for the
CryoSat mission.

"It wasn't really difficult to take these measurements for CryoSat," said
Alain, "It became part of our routine. The difficult part of the expedition
was putting one foot in front of the other when the ice is breaking up
around you. As co-founder of the International Polar Foundation, a scientist
as well as a seasoned explorer -- I aim to form a kind of 'bridge' between
science and society. Observing the changes that are occurring in the fragile
Arctic environment will help lead to a better understanding of the effects
of climate change, and ultimately the Earth system as a whole. CryoSat is an
exciting mission that will help answer questions about the polar ice so we
were very happy to contribute through our Arctic Arc expedition."

Since the Earth Explorer CryoSat mission, which is due for launch next year,
is designed to measure tiny variations in the thickness of floating sea-ice
and ice on land, understanding the effects that the overlying snow can have
on the measurement of ice elevation is of huge importance. To this end, ESA
has in place a dedicated validation programme that involves a number of
field campaigns in the polar regions. Measurements collected on the ice and
from the air are crucial to fully understand and characterise the
geophysical uncertainties in the CryoSat products so that the data CryoSat
delivers is interpreted as accurately as possible.

During a presentation held this week at ESA-ESTEC in the Netherlands Alain
handed over the dataset to Richard Francis ESA's Project Manager for
CryoSat, who commented that, "While snow-depth information holds the key to
producing accurate maps of ice-thickness change over time, there are
relatively few basic ground-measurements readily available. So when Alain
offered to take measurements during his expedition, the CryoSat project was
extremely grateful."

In turn, Alain and Dixie were also grateful for help provided by an existing
ESA satellite. Under the ongoing ESA Project Polar View, which is delivering
logistical support to IPY, they were able to rely on images from Envisat to
guide them through some dangerous ice-break up. Alain explained, "As we
approached the coast of northern Greenland, the sea ice in the Lincoln Sea
began to break up chaotically -- something we really weren't expecting. We
realised there was no way we could take our planned route to reach land.
Fortunately, however, we were guided by expedition router who relied on
information provided by the Danish Technical University using data from
ESA's Envisat satellite to help us circumnavigate the open waters and
eventually reach land safely."

Malcolm Davidson ESA's CryoSat Validation Manager noted that, "ESA has now
released the snow-depth data collected by the Arctic Arc expedition to the
CryoSat Validation and Retrieval Team. The team has been quite eager to get
the data and start the analysis. Ultimately we expect that -- in conjunction
with the core ESA-sponsored airborne campaigns and similar initiatives from
other polar expeditions -- the data will help us better measure
ice-thickness changes over time from space with CryoSat-2."

[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMNJE1YUFF_index_1.html ]
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