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CLIMATE CHANGE: Polar Satellite Still in
Planning Stage
By Julio Godoy*
BERLIN (Tierramérica) - When the European
Space Agency (ESA) designed the original
CryoSat ice-monitoring satellite, not all
scientists accepted global warming as an
urgent threat.
Today, 10 years later, few deny the
existence of climate change, its human
causes, and the consequences for life on the
planet. But CryoSat-2 is still just a
project, held up by the red tape and
technical shortcomings that are typical in
this kind of mission.
The objective of the satellite is to obtain
precise measurements of the changes in polar
ice masses, with the aim of determining the
effects of global warming on the Arctic and
Antarctic regions.
Initially scheduled to be launched into
orbit in October 2005, over the following
three and a half years it was to gather data
that would serve as scientific grounds for
debates on how to limit or reduce greenhouse
gas emissions.
But the first CryoSat crashed due to
technical problems in the rocket launcher,
and the ESA will only be ready to try a new
launch in November of this year.
In the more than three years that have gone
by since the first attempt, considerable
knowledge has been obtained on the melting
of the earth’s ice cover.
The most comprehensive study conducted to
date on North Pole life - presented in
February by the organisation Arctic Ocean
Diversity - found that a rising number of
warm-water crustaceans have extended their
range towards the poles, inhabiting
previously cold waters, like those
surrounding the Norwegian Svalbard Islands,
which have become warmer and more hospitable
as a result of climate change.
Despite all the new findings, the ESA
believes that CryoSat’s mission will still
prove useful.
"Our understanding of global warming and ice
mass melting has obviously grown. But the
technology used by the CryoSat will allow us
to obtain the most accurate measurements
ever on glacier volume changes in both
poles," Daniel Steinhage, glaciologist with
the German Alfred Wegener Institute for
Polar and Marine Research and scientific
advisor to the CryoSat mission, told
Tierramérica.
Nonetheless, he admitted that CryoSat-2
observations would not be in on time for the
United Nations climate change conference
scheduled for Dec. 7-18 in Copenhagen, with
the purpose of reaching a new international
climate change agreement that will replace
the Kyoto Protocol, set to expire in 2012.
"That doesn’t mean that the data obtained by
CryoSat-2 won’t constitute a useful input
for the scientific debate on global
warming," Steinhage said.
Starting in mid November, the satellite will
orbit the earth for 42 months at an altitude
of 717 kilometres, with an unusually high
inclination that will enable it to achieve
latitudes of up to 88 degrees in the two
poles.
"Due to geometrical reasons, it’s very
difficult to maintain an orbit around the
earth at latitudes of 88 degrees, both in
the north and south," Steinhage explained.
These latitudes are a blind spot for most of
the satellites that orbit the earth around
the two poles.
"That is why the polar images and
measurements currently available are
incomplete. CryoSat-2 will fill in those
gaps, obtaining new data on the geology of
the poles and the ice masses," he added.
The satellite will be able to take highly
precise measurements using its
interferometric radar, which, unlike
traditional radars, is equipped with two
antennae that emit electromagnetic signals
and receive their echoes reflected by the
ice surface at the poles.
The antennae function like human eyes,
allowing a three dimensional view of the
polar masses.
The radar "can accurately measure the energy
echoed from the ice sheets’ reflection
surface, regardless of the angle," Steinhage
said.
This will enable three-dimensional
measurements to be taken both of the
thickness of the ice sheets at sea level in
both poles and their changes from one year
to the next, as well as of the slightest
changes in the surface.
The interferometric radar will provide
essential data on the pattern of ocean
currents at the edge of the ice masses,
which will be correlated to the rate of
meltdown to determine changes in the long
term, Duncan Wingham, professor of climate
physics at the University College London,
explained to Tierramérica.
Wingham pointed out that "CryoSat uses
radars that emit microwaves instead of
simple magnetic waves, thus increasing the
accuracy of its measurements."
As the satellite will orbit over both the
North and South Poles, its measurements will
serve to verify or rectify the observations
made to date on the rate of meltdown of the
Arctic and Antarctic ice caps.
"We need to know if these changes are
compensating each other, and what the
mechanisms of transmission through oceans
are," Steinhage said.
(*This story was originally published by
Latin American newspapers that are part of
the Tierramérica network. Tierramérica is a
specialised news service produced by IPS
with the backing of the United Nations
Development Programme, United Nations
Environment Programme and the World Bank.)
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