Cryo2ice for better measurements of ice, snow and polar oceans

Cryo2ice brings together two of the world’s greatest ever ice missions, ESA’s CryoSat and NASA’s ICESat-2, to gather data from each satellite over the same stretches of ice at approximately the same time.

CryoSat and ICESat-2 are the only satellite altimeters in existence measuring as far north and south as 88ᵒ and are key to our ongoing efforts to monitor the rapidly changing polar regions.

The Cryo2ice partnership began in 2020, when the CryoSat team at ESA’s mission control centre in Darmstadt, Germany performed a series of manoeuvres to bring the orbits of the two satellites closer together over the Arctic. Two years later, another tweak to CryoSat’s orbit switched the focus to Antarctica, instead.

Since the adjustment to CryoSat’s orbit, the time between collocated measurements of CryoSat and ICESat-2 has been slowly reducing, meaning that in early 2025 the two satellites will provide quasi-simultaneous measurements. It will be a boost to researchers studying sea ice, as the closer together in time between measurements, the less the sea ice will have moved, giving a more accurate snapshot of the same ice.

CryoSat’s radar and ICESat-2’s lidar both measure the elevation of sea ice and land ice by sending signals down to Earth and then detecting radar echoes and photons backscattered off the surface, but there are differences. For example, penetration of the radar and lidar signals can be different in the snowpack on top of ice. The thickness of snow on sea ice remains one of the biggest uncertainties in our estimates of ice using satellite altimetry, and Cryo2ice offers a unique opportunity to measure it more accurately.