Probing Greenland’s ice sheet for future satellites
With a helicopter the sole feature on the vast expanse of ice and her only way back to warmth and safety, polar scientist Anna Hogg must have thought, “What on Earth am I doing out here?” as she set to taking ice samples.
Anna and fellow scientist Andrew Shepherd, from the University of Leeds in the UK, spent two days extracting long cylindrical ice cores and using instruments to probe the ice sheet as part of an international effort to develop new space technology to monitor our changing polar environment.
Since it was launched in 2010, ESA’s CryoSat has been delivering vital information about how the thickness of Earth’s ice is changing. To do this, the satellite carries a radar altimeter, and now scientists want to find out if an altimeter working at two wavelengths would provide even better information in the future.
So, as well as work on the ice, the experiment included taking measurements from an aircraft carrying two radar altimeters: one working at ‘Ka-band’ radio wavelengths less than 1 cm (8 mm) long and the other at ‘Ku-band’ around 2.2 cm.
While Anna and Andrew braved the cold down on the ice sheet, scientists from the Technical University of Denmark and Metasensing operated the complex radar instruments on the plane, focusing their attention on the precious data being collected as they flew back and forth across the ice sheet.
Henriette Skourup, in charge of the airborne measurements, said, “CryoSat relies on a Ku-band radar altimeter to map how the height of the ice caps change over time. Because it has a shorter wavelength, Ka-band penetrates the snow less and therefore provides useful complementary information on ice-sheet topography.
“By comparing airborne and ground data, the campaign will provide valuable feedback on the benefits we expect from Ka-band measurements.”
Malcolm Davidson, ESA campaign coordinator, added, “Before any new space technology can be built, a huge effort goes into prototyping the measurements.
“In this case, we need to understand how a two-wavelength radar altimeter could offer continuity and improve the current single-wavelength measurements provided by CryoSat.
“The results from the campaign should help us, together with European space industry, to design future space missions to monitor polar regions.
“Earth’s ice is extremely vulnerable, so it is important that we investigate different ways it could be measured in the future.”
After some well-deserved rest, the campaign team are now busy processing and analysing the data they collected in Greenland and will have the first results before the end of the year.