Ice measurement - CryoSat-2 satellite launches on mission to monitor climate change in Arctic

9/4/2010 Guardian A resurrected satellite, carrying the hopes of climate scientists, successfullymade a second attempt to reach orbit today from the Baikonur cosmodrome in
Kazakhstan.The first CryoSat satellite crashed minutes after launch in 2005,
ditching - with cruel irony - into the Arctic Ocean it was meant to study.
The €140m (£122m) CryoSat-2 is a replica built by the European Space Agency, but
with some additional instruments. The satellite is currently in orbit after a
successful separation and has sent communication signals which have been
received by a ground team in Malindi, Kenya. The satellite will be able to
measure the thickness of Arctic and Antarctic ice to within a centimetre - an
accuracy unmatched until now. Lift-off was shown live online and took place
during the scheduled launch of 1457 BST.
The melting of sea ice, ice caps and glaciers across the planet is one of the
clearest signs of global warming and the UK-led team of scientists will use the
data from CryoSat-2 to track how this is affecting ocean currents, sea levels
and the overall global climate.
Duncan Wingham, a climate physicist at University College London and the lead
scientist for both missions, is hoping this will be second time lucky.
“Satellites have transformed our knowledge of what is happening to these distant
and uninhabited parts of the planet. CryoSat-2 will help unravel the
consequences of the dramatic changes in the poles that we’ve seen in the past
two decades.”
Wingham said that, without CryoSat-2, there would be a significant gap in the
data needed to track climate change. “The data we do have is patchy because the
instrumentation on the earlier generation of satellites was not designed to deal
with the ice-sheets,” said Wingham.
The first CryoSat mission was launched from the Plesetsk cosmodrome in northern
Russia on 8 October 2005, but it crashed into the icy sea shortly afterwards,
due to a malfunction in the launch vehicle.
Approval for a successor mission to CryoSat was given by Esa within months of
the accident. The new probe was built using improved electronics and batteries,
and an extra radar altimeter, a device that will fire microwaves at the Arctic
and Antarctic ice to reveal its thickness.
Scientists have already shown that the amount of sea ice in the Arctic is
falling, and the latest data confirms the long-term trend. But some data also
suggests that the ice that remains is thinning. If the measurements from
CryoSat-2 bear out this thinning theory, it would mean the ice is being lost
more quickly. Scientists are concerned that the loss of sea ice is leading to a
feedback effect where the newly exposed, darker ocean absorbs more sunlight,
warming the water yet further. In addition, sea ice can block glaciers on land
from falling into the ocean, so its loss could raise sea levels.
“We are altering the Arctic climate far faster than anywhere else on Earth,”
said Wingham. “We’re changing the whole structure of the Arctic Ocean, but we
still don’t know what the consequences will be. We have to find out what is
going on up there. CryoSat-2 will do that.”
Another antenna on CryoSat-2 will measure the shape of the ice and tell
researchers about slopes and ridges at the edges of the great Antarctic and
Greenland ice sheets.
Alan O’Neill, director of the National Centre for Earth Observation at the
University of Reading said: “These measurements are absolutely crucial to our
understanding of climate variability and climate change. Not only are they early
indicators of climate change because of feedbacks in the system. But they’re not
remote from what affects people’s lives and the weather that affects the rest of
the planet. The polar regions are connected to the rest of the planet by the
atmosphere and the ocean.”
Richard Francis of Esa, who led the team that built CryoSat-2, said scientists
were holding their breath until launch. “There’ll be a lot of relief when we
acquire that signal [after launch], I can tell you.”

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