Land ice altimetry

CPOM uses radar altimetry to investigate ongoing changes in the Earth’s land ice masses, focusing on Antarctica and Greenland.

Observing how these ice masses are changing is critical because it tells us how ice melt is affecting global sea levels, and also allows us to investigate, and better understand, how climate change is affecting these vast, yet remote, ice bodies.

We use altimetry to do this because of the level of detail it can provide: a monthly record spanning several decades, with a resolution that allows us to identify changes occurring across individual glaciers or whole ice sheet sectors.

Thanks to CryoSat-2, advances in radar altimetry instrument technology and processing now allow us to study the Antarctic and Greenland ice sheets in unprecedented detail.  By combining CryoSat’s data with that from older altimetry missions, we have been able to chart the increasing contribution of the ice sheets to global sea levels and investigate how key glaciers have behaved over recent decades.  In addition, we are now using ESA’s Sentinel-3 mission to add to our polar monitoring efforts.

Copernicus Sentinel-3 satellite maps Antarctic Ice Sheet elevation change: Antarctic Ice Sheet elevation change mapped by Copernicus Sentinel-3A between 2016 and 2018. Contains modified Copernicus Sentinel data (2018)/processed by CPOM/McMillan

In West Antarctica, we are using the long term altimeter record to track the increasing signal of dynamic imbalance, as warm water thins the ice shelves that flow into the Amundsen Sea. This has revealed that almost a quarter of West Antarctica’s ice is now unstable.  We are also using CryoSat’s high resolution to investigate the detailed pattern of melting underneath these ice shelves.

In Greenland, CryoSat has revealed the detailed spatial and temporal pattern of mass loss from the ice sheet.  These are being combined with data from climate models to identify “hot-spots”, where glaciers are in a state of dynamic imbalance and rapidly discharging ice into the ocean, and also show how the ice sheet responds to year-to-year variations in the intensity of summer melting.

Read more about how Greenland’s ice is melting and the mass balance of the Greenland and Antarctic Ice Sheets on our blog.