The great news here is that ground truth is now been established to
allow a rigorous interpretation of
CryoSat data that has now been collected for two years. It appears we will finally really know what
the net ice growth is every winter.
Having to watch everyone guess and come up with outright contradictory
positions over the past several years, it cannot arrive too soon to end what
has been a lot of self serving opinion.
At present, it appears that the
ice regime may be fairly stable, but at a level that is historically low. It could well be that this is the natural
warm undisturbed system that we normally arrive at when we pass through years of minimal volcanic interference. The trouble is that we will not know until we
have centuries of data to compare.
Beyond that it appears that the data problems are on the way to been
solved.
ESA, NASA Join Forces To
Measure Arctic Sea Ice
April 5, 2012
Marking another remarkable
collaborative effort, ESA and NASA met up over the Arctic Ocean this week to
perform some carefully coordinated flights directly under CryoSat orbiting
above. The data gathered help ensure the accuracy of ESA’s ice mission.
The aim of this large-scale
campaign was to record sea-ice thickness and conditions of the ice exactly
along the line traced by ESA’s CryoSat satellite orbiting high above. A range
of sensors installed on the different aircraft was used to gather complementary
information.
These airborne instruments
included simple cameras to get a visual record of the sea ice, laser scanners
to clearly map the height of the ice, an ice-thickness sensor called EM-Bird
along with ESA’s sophisticated radar altimeter called ASIRAS and NASA’s snow
and Ku-band radars, which mimic CryoSat’s measurements but at a higher
resolution.
In orbit for two years,
CryoSat carries the first radar altimeter of its kind to monitor changes in the
thickness of ice.
As with any Earth observation
mission, it is important to validate the readings acquired from space. This
involves comparing the satellite data with measurements taken in situ, usually
on the ground and from the air.
The teams of scientists from
Europe, US and Canada expect that by pooling flight time and the results they
will get a much-improved accuracy of global ice-thickness trends measured by
CryoSat and NASA’s IceSat.
This will, in turn, lead to a
better understanding of the impact of climate change on the Arctic environment.
Rene Forsberg, from the
Technical University of Denmark’s National Space Institute, said, “As a
scientist I value the collaboration very much.
“Data from a particular
instrument provides one piece of the puzzle. Through experience in combining
gravity and altimetry measurements over ice sheets, I’ve found that by
combining measurements from different instruments you can solve the puzzle more
easily and move forward.”
Coordinated campaign
activities in these extremely cold and remote locations are difficult and
include numerous challenges. The most obvious is the extreme weather. While
much of Europe and North America is now enjoying the spring weather, temperatures
in the high Arctic still often dip below –30° C.
These cold temperatures
present challenges in running the aircraft and the complex scientific
instruments on board, and of course, for the participants.
Distance and time zones are
another challenge, because the NASA team is located in Thule, Greenland, and
the ESA team is in Alert, Canada. Last, but not least, ESA’s satellite
operations, such as orbit maneuvers and instrument settings, need to be
coordinated with field activities to maximize the scientific return.
Despite these and many other
challenges, the joint flights proved a resounding success.
On two occasions during the
past week as the CryoSat satellite came over the horizon on the other side of
the Arctic Ocean and raced across the frozen sea at over 6 km/second, the ESA
and NASA planes met up along the coast and headed out over the frozen water
within meters of each other to follow the line traced by CryoSat.
NASA’s Icebridge Project
Scientist, Michael Studinger, said, “The joint ESA/NASA campaign has been
incredibly successful again.
“It would be easy to view such
a success as ordinary and lose sight of how difficult this whole undertaking
really is. The skill and experience of all teams involved is the foundation for
safety of operations and success in such an extreme environment.”
Malcolm Davidson, ESA’s
CryoSat Validation Manager, added, “By joining forces and pooling their
efforts, ESA and NASA are able to achieve much more than each agency would
separately.
“The joint activities this
week provide a vivid illustration of the many synergies that such a
collaboration brings.”
—
Image Caption: A view of
Arctic sea ice from NASA’s P-3 aircraft as it joins ESA to validate
measurements of the ice taken from space by CryoSat. On 2 April, ESA and NASA
planes flew together across the Arctic Ocean, exactly under CryoSat orbiting
700 km above. Credits: NASA/M. Studinger
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