Arctic explorer delivers unique snow-depth data for CryoSat   Crossing open water or 'leads' during the Alain Hubert's 1600 km Arctic Arc 2007. The 106-day trek across the floating Arctic sea-ice took Alain and fellow explorer Dixie Dansercoer from Russia to northern Greenland via the North Pole – a route never before attempted. Despite the gruelling conditions, Alain and Dixie to the time to take snow-depth measurements that make a valuable contribution to the validation programme for ESA's ice mission CryoSat.   Taking snow-depth measurements for ESA's CryoSat mission during Alain Hubert's 1600 km trek across the Arctic sea-ice.   CryoSat is able to measure the freeboard (the height protruding above the water) of floating sea ice with its sensitive altimeter. From the freeboard, the ice thickness can be estimated.   During a visit to ESA-ESTEC in the Netherlands, intrepid polar explorer Alain Hubert described his 106-day expedition to the Arctic. Alain also handed over the snow-depth data he had collected during the expedition to Richard Francis who is Project Manager for the CryoSat mission. The data collected will make a valuable contribution to the overall mission validation programme.   Struggling over rough sea-ice during the Arctic Arc expedition. Making headway over the sea ice can be very difficult. Sometimes compression zones can be up to five metres high and open stretches of water 'leads' caused problems for the expedition.   The EM Bird was used extensively during CryoVEx 2008 to measure sea-ice thickness. Using the EM Bird on the helicopter scientists can measure sea-ice thickness over many kilometres. Release date: 16 January 2009