Credit: ESA - AOES Medialab
Ambitious Polar Satellite Still in Planning Stage
By Julio Godoy
If everything goes according to plan, in November the European Space Agency will launch CryoSat-2, in what will be the second attempt to put a polar satellite in orbit to explore the state of the earth’s cryosphere.
BERLIN, Mar 9 (Tierramérica).- When the European Space Agency (ESA) designed the original CryoSat ice-monitoring satellite, only a handful of scientists and environmentalists accepted global warming as a real threat.
Today, 10 years later, few deny the existence of climate change, its causes, and the consequences for life on the planet. But CryoSat-2 is still a project, delayed by the bureaucracy and technical shortcomings that are typical in this kind of missions.
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 organization 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 the 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 arrive on time for the United Nations climate change conference scheduled for Dec. 7-18 in Copenhagen to reach a new international climate change agreement that will replace the Kyoto Protocol, set to expire in 2012.
“That doesn’t mean that the data that will be 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 kilometers, 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 on 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 Pole, 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 stressed.