Andrew Yee[_1_]
May 12th 08, 05:09 PM
ESA News
http://www.esa.int
9 May 2008
Scientists endure Arctic for last campaign prior to CryoSat-2 launch
An international group of scientists has swapped their comfortable offices
for one of the most inhospitable environments on the planet to carry out a
challenging field campaign that is seen as the key to ensuring the data
delivered by ESA's ice mission CryoSat will be as accurate as possible.
The scientists, mainly from Denmark, UK, Germany and Canada, are currently
in the middle of CryoSat Validation Experiment (CryoVEx) 2008, an extensive
three-week experiment programme in the far north of Greenland and Canada.
CryoVEx 2008 is a continuation of a number of earlier campaigns that focus
on collecting data on the properties snow and ice over land and sea.
The data collected during the campaigns will later enable scientists to
accurately interpret the variations in ice thickness with time, which will
be measured by the Earth Explorer CryoSat mission.
Although CryoVEx 2008 builds on previous exercises and the scientists are
fairly seasoned when it comes to enduring the harsh Arctic environment, this
year's campaign is a huge logistical undertaking as airborne, helicopter and
ground measurements are being taken simultaneously in three different
locations -- out on the floating sea-ice north of the Canadian Forces
Station Alert, on the Devon ice cap in Canada and on the vast Greenland ice
cap.
The campaign includes a unique experiment in northern Greenland where the
'cold' ice is assumed to be similar to large parts of Antarctica. Accessing
the planned northern areas has been particularly complicated due to limited
infrastructure, military permits, unforgiving weather, large distances and a
host of other constraints.
Despite these constraints, the range of equipment put to the service of the
campaign is impressive. They include a Twin Otter carrying on-board the two
key instruments for the investigations: ASIRAS, a radar altimeter that
mimics the radar altimeter on-board CryoSat-2 and a laser scanner which maps
the surface beneath the plan, and a helicopter with an on-board sensor that
measures sea-ice thickness.
A second Twin-Otter is being used to position UK and Canadian scientists on
the Greenland Ice Sheet, Devon Ice Cap and Alert and US and Canadian
military aircraft are put into action to transport fuel to the Alert station
and scientists.
"One of the key experiments will be to acquire coincident airborne and
helicopter measurements over sea ice," says Rene Forsberg from the Danish
National Space Centre who is responsible for the airborne programme. "In two
previous campaigns we have been only partially successful and we would
really like to know whether this novel experimental activity is possible and
can contribute to the validation of CryoSat data over sea ice."
Launching in 2009, CryoSat-2 is specifically aimed at advancing our
understanding of polar ice cover and its response to climate change.
CryoSat-2 will measure fluctuations in the thickness of ice both on land and
floating in the sea to provide a clear picture of the influence that climate
change is having on the Earth's polar ice masses.
There are many challenges associated with building, launching and
successfully operating an Earth Observation satellite and amongst the list
of challenges is making sure that the resulting data is as accurate and
meaningful as possible, which includes an assessment of the extent to which
they may be in error.
As the CryoSat signal is sensitive to variations in the properties of snow
and ice, it is crucial to understand, and then correct for, changes that
occur naturally so that long-term trends can be determined with the highest
possible precision.
ESA has therefore gone to considerable lengths to organise the series of
CryoVEx campaigns in the Arctic to simulate the measurements that CryoSat-2
will take. This includes flying an airborne version of the CryoSat-2 radar
altimeter and a laser altimeter to take measurements of ice while teams on
the ground take measurements as the plane passes over.
Malcolm Davidson, ESA's CryoSat-2 Validation Manager explains, "As the
airborne measurements have a much higher resolution than measurements made
from a satellite, scientists can use the CryoVEx campaign to make direct
comparisons between ground and airborne measurements. The knowledge gained
with local measurements is then extrapolated to a global scale to predict
the influence of snow and ice properties on the CryoSat-2 measurements from
space."
Already halfway through the campaign, a huge amount of data has already been
successfully collected and scientists look forward to completing the
campaign with the knowledge that their hard work will go a long way in
helping the CryoSat mission reach its goal of measuring ice-thickness change
with unprecedented accuracy.
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMWGM2QGFF_index_1.html ]
http://www.esa.int
9 May 2008
Scientists endure Arctic for last campaign prior to CryoSat-2 launch
An international group of scientists has swapped their comfortable offices
for one of the most inhospitable environments on the planet to carry out a
challenging field campaign that is seen as the key to ensuring the data
delivered by ESA's ice mission CryoSat will be as accurate as possible.
The scientists, mainly from Denmark, UK, Germany and Canada, are currently
in the middle of CryoSat Validation Experiment (CryoVEx) 2008, an extensive
three-week experiment programme in the far north of Greenland and Canada.
CryoVEx 2008 is a continuation of a number of earlier campaigns that focus
on collecting data on the properties snow and ice over land and sea.
The data collected during the campaigns will later enable scientists to
accurately interpret the variations in ice thickness with time, which will
be measured by the Earth Explorer CryoSat mission.
Although CryoVEx 2008 builds on previous exercises and the scientists are
fairly seasoned when it comes to enduring the harsh Arctic environment, this
year's campaign is a huge logistical undertaking as airborne, helicopter and
ground measurements are being taken simultaneously in three different
locations -- out on the floating sea-ice north of the Canadian Forces
Station Alert, on the Devon ice cap in Canada and on the vast Greenland ice
cap.
The campaign includes a unique experiment in northern Greenland where the
'cold' ice is assumed to be similar to large parts of Antarctica. Accessing
the planned northern areas has been particularly complicated due to limited
infrastructure, military permits, unforgiving weather, large distances and a
host of other constraints.
Despite these constraints, the range of equipment put to the service of the
campaign is impressive. They include a Twin Otter carrying on-board the two
key instruments for the investigations: ASIRAS, a radar altimeter that
mimics the radar altimeter on-board CryoSat-2 and a laser scanner which maps
the surface beneath the plan, and a helicopter with an on-board sensor that
measures sea-ice thickness.
A second Twin-Otter is being used to position UK and Canadian scientists on
the Greenland Ice Sheet, Devon Ice Cap and Alert and US and Canadian
military aircraft are put into action to transport fuel to the Alert station
and scientists.
"One of the key experiments will be to acquire coincident airborne and
helicopter measurements over sea ice," says Rene Forsberg from the Danish
National Space Centre who is responsible for the airborne programme. "In two
previous campaigns we have been only partially successful and we would
really like to know whether this novel experimental activity is possible and
can contribute to the validation of CryoSat data over sea ice."
Launching in 2009, CryoSat-2 is specifically aimed at advancing our
understanding of polar ice cover and its response to climate change.
CryoSat-2 will measure fluctuations in the thickness of ice both on land and
floating in the sea to provide a clear picture of the influence that climate
change is having on the Earth's polar ice masses.
There are many challenges associated with building, launching and
successfully operating an Earth Observation satellite and amongst the list
of challenges is making sure that the resulting data is as accurate and
meaningful as possible, which includes an assessment of the extent to which
they may be in error.
As the CryoSat signal is sensitive to variations in the properties of snow
and ice, it is crucial to understand, and then correct for, changes that
occur naturally so that long-term trends can be determined with the highest
possible precision.
ESA has therefore gone to considerable lengths to organise the series of
CryoVEx campaigns in the Arctic to simulate the measurements that CryoSat-2
will take. This includes flying an airborne version of the CryoSat-2 radar
altimeter and a laser altimeter to take measurements of ice while teams on
the ground take measurements as the plane passes over.
Malcolm Davidson, ESA's CryoSat-2 Validation Manager explains, "As the
airborne measurements have a much higher resolution than measurements made
from a satellite, scientists can use the CryoVEx campaign to make direct
comparisons between ground and airborne measurements. The knowledge gained
with local measurements is then extrapolated to a global scale to predict
the influence of snow and ice properties on the CryoSat-2 measurements from
space."
Already halfway through the campaign, a huge amount of data has already been
successfully collected and scientists look forward to completing the
campaign with the knowledge that their hard work will go a long way in
helping the CryoSat mission reach its goal of measuring ice-thickness change
with unprecedented accuracy.
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaCP/SEMWGM2QGFF_index_1.html ]