Herstmonceux scientists keep an eye on ice caps

FAR above the volcanic ash cloud, a satellite is keeping a beady eye on the movements of polar ice sheets – and in turn, it is being closely monitored by a team of scientists based at Herstmonceux.

The Space Geodesy Facility is observing the European Space Agency's CryoSat-2 satellite, which was launched into space earlier this month in a bid to help experts understand how the earth's ice may be affected by future climate change.

The satellite is orbiting at an altitude of 720 kilometres and maps the Earth by reflecting radio signals off land, sea and ice surfaces.

The objective is to measure the thickness of sea-ice and the surface elevation of ice sheets in both the northern and southern hemispheres.

The CryoSat-2 satellite follows the original CryoSat mission, which was lost in October 2005 when a Russian rocket failed to separate and plunged into the Arctic Ocean.

The mission will help scientists better understand the dynamics of polar ice sheets and the impact that future climate change will have in these processes.

The Earth's ice plays an important role in regulating climate, ocean circulation patterns and sea level and the consequences of change are far reaching.

"We're very pleased to play a part in this timely mission," said head of facility, Dr. Graham Appleby.

"The Earth is a highly complex system and satellite observations are increasingly important as they are the only way to get a global perspective."

The NERC Space Geodesy Facility tracks a veriety of scientific satellites by firing a short pulse of green laser light to a satellite and detecting a reflected signal back at the facility in a telescope.

The time interval between the laser fire and detection of the return signal determines the range to the satellite.

A single range measurement is made to a precision of just a few millimetres.

The range data is combined with data from similar facilities around the world and used to determine precise orbits and confirm the onboard positioning of the satellite.

If the skies remain clear above Herstmonceux, the facility will continue to track CryoSat-2 day and night, four times a day, for its expected lifetime of three years.