ESA and NASA met up for a remarkable collaborative effort over the Arctic Ocean last week, to perform some carefully coordinated flights directly under CryoSat orbiting high above. The aim is to record sea-ice thickness and conditions of the ice exactly along the line traced by the satellite.
Image above: A view of Arctic sea ice from NASA’s P-3 aircraft as it joins ESA to validate measurements of the ice taken from space by CryoSat. On 2 April, ESA and NASA planes flew together across the Arctic Ocean, exactly under CryoSat orbiting 700 km above.
A ‘digital mapping system’ mosaic of a lead in the Arctic sea ice from NASA’s P-3 aircraft.
Credits: NASA/ E. Fraim
A range of sensors installed on the different aircraft was used to gather complementary information. These airborne instruments included simple cameras to get a visual record of the sea ice, laser scanners to clearly map the height of the ice, an ice-thickness sensor called EM-Bird along with ESA’s sophisticated radar altimeter called ASIRAS and NASA’s snow and Ku-band radars, which mimic CryoSat’s measurements but at a higher resolution.
In orbit for two years, CryoSat carries the first radar altimeter of its kind to monitor changes in the thickness of ice.
As with any Earth observation mission, it is important to validate the readings acquired from space. This involves comparing the satellite data with measurements taken in situ, usually on the ground and from the air.
The teams of scientists from Europe, US and Canada expect that by pooling flight time and the results they will get a much-improved accuracy of global ice-thickness trends measured by CryoSat and NASA’s IceSat.
This will, in turn, lead to a better understanding of the impact of climate change on the Arctic environment.