Date: 7 June 1999
An innovative UK-led space mission to study the shrinkage of Arctic sea ice has been selected as the pioneering mission in the European Space Agencys new Living Planet programme. Known as CRYOSAT, the mission was chosen ahead of 26 other proposals submitted from all over Europe. The announcement was made by the UK Space Minister, Lord Sainsbury, who is currently chairman of the ESA Ministerial Council, and Antonio Rodota, ESAs Director General, at a press briefing held in London earlier today.
The 350 kg CRYOSAT, which is expected to be launched into a near-polar orbit in 2002, will be dedicated to a two year study of polar sea ice. Lead scientist on the mission will be Professor Duncan Wingham of University College, London, who has spent many years studying polar ice with radar satellites.
CRYOSATs radar will enable it to see in darkness and in all weathers at least 85% of the ice floating on the surface of the Arctic Ocean. The satellite will carry two radar altimeters, spaced one metre apart, to obtain high resolution synthetic aperture radar observations of the surface features as it passes overhead.
Even more significant, however, will be the use of a computer processing technique known as interferometry. This allows scientists to combine the radar signals which are bounced off the planets surface and received by each instrument in order to create a three-dimensional view of the surface variations in the sea ice.
This technique will enable CRYOSAT to measure the thickness of polar sea ice. Although ice floes are typically 2 - 6 metres thick, only 10% of this (20 - 60 cm) can be seen above sea level. The object of the mission is to measure these differences in height, and so determine the thickness of the underlying ice. If the sea ice is melting and thinning, this should show up in the data returned by the satellite.
Were interested in how much ice changes into water, said Professor Wingham. We measure this to calculate the mass of melted ice entering the oceans.
Although Arctic sea ice has not so far been studied in detail, it is a particularly important factor in models of the global environment - much more so than Antarctic sea ice, which shrinks back to the coasts every summer because it is much thinner and largely restricted to inshore waters.
If the Arctic ice cap was to melt and disintegrate, the consequences could be catastrophic. With no ice to reflect sunlight and heat in the summer, the entire radiation balance of the Earth would change. This would lead to major shifts in ocean currents, particularly in the North Atlantic, leading to alterations in the thermo-haline ocean circulation system which transfers heat and minerals around the planet. The end result would be dramatic global climate change and unpredictable disruption to the oceanic food chain.
Notes for Editors
CRYOSAT was selected as the first Earth Explorer opportunity mission under ESAs new Living Planet programme. It was chosen from 27 study proposals which covered all aspects of Earth science, Earths atmosphere, land surface, oceans and polar caps.
ESA has already selected a second candidate small-scale opportunity mission - known as Soil Moisture and Ocean Salinity. This proposal is led by French scientists, but has strong NERC involvement through co-investigators at the Southampton Oceanography Centre and the Institute of Hydrology. A decision about whether it will be adopted will be made when the funding situation has been clarified.
The Living Planet programme was given the go-ahead at a meeting of the ESA Ministerial Council in Brussels on 11-12 May. It will be implemented in a series of five-year-long stages. The first stage of the programme (1999-2002) will be funded by ESA at a level of 593 million Euro (about 400 million pounds). The UK has pledged a contribution of 14% (approximately 67 million pounds) towards the programme through the DTI and the Natural Environment Research Council (NERC).
ESAs opportunity missions will be strictly budget limited with the agency committed to provide funding of no more than 80 million Euro (about 54 million pounds) towards each of the opportunity missions. Additional funding will be requested from other sources, including industry.