ESA and NASA satellites deliver first joint picture of Greenland Ice Sheet melting

Global warming causes ice caps to melt and flow faster, causing sea levels to rise and disrupting weather patterns on Earth.

Precisely measuring changes in their shape is therefore crucial to tracking and adapting to the effects of a warming climate.

Scientists have now measured changes in Greenland ice sheet thickness for the first time using CryoSat-2 and ICESat-2, the European Space Agency and NASA Ice Satellite missions.

Both satellites carry altimeters as their primary sensors, but they use different techniques to collect measurements.

CryoSat-2 carries a radar system to determine the height of the Earth’s surface, while ICESat-2 has a laser system for the same mission.

Although radar signals can pass through clouds, they also penetrate the surface of the ice sheet and must be adjusted for this effect.

Laser signals, on the other hand, reflect off actual surfaces, but they don’t work when clouds are present.

The missions are therefore highly complementary, and combining their measurements has been the holy grail of polar science.

A new study by scientists at the UK Center for Polar Observation and Modeling (CPOM) at Northumbria University is published in Geophysical Research Letters It shows that CryoSat-2 and ICESat-2 measurements of Greenland ice sheet elevation changes are consistent within 3%.

This confirms that combining these satellites can achieve more reliable estimates of ice loss than either satellite alone. It also means that if one mission fails, another can be relied upon to maintain our record of changes in polar ice.

Between 2010 and 2023, the Greenland ice sheet thinned by an average of 1.2 meters. However, the thickness of the ice sheet edge (the ablation zone) became more than five times thinner, reaching an average of 6.4 meters.

The most extreme thinning occurs in the ice sheet’s outlet glaciers, many of which are thinning at an accelerated rate.

At Sermeq Kujalleq (also known as Jakobshavn Isbræ) in west-central Greenland, the peak thinned by 67 meters, while at Zachariae Isstrøm in northeastern Greenland, the peak thinned by 75 meters.

During the 13-year survey period, the ice sheet shrank by a total of 2,347 cubic kilometers, enough to fill Africa’s Lake Victoria.

The biggest changes occurred between 2012 and 2019, when summer temperatures were extremely hot and the ice sheet lost more than 400 cubic kilometers of volume each year.

Greenland’s melting ice also affects global ocean circulation and disrupts weather patterns. These changes have profound impacts on ecosystems and communities around the world.

Obtaining accurate, up-to-date data on ice sheet changes is critical to helping us prepare for and adapt to the impacts of climate change.

“We are very pleased to find that CryoSat-2 and ICESat-2 are so closely aligned,” said lead author and CPOM researcher Nitin Ravinder.

“Their complementarity provides strong motivation to combine data sets to improve estimates of ice sheet volume and mass changes.

“Since ice sheet mass loss is a key contributor to global sea level rise, this is very useful to the scientific community and policymakers.”

The study draws on four years of measurements from both missions, including those collected during the Cryo2ice campaign, a groundbreaking partnership between ESA and NASA launched in 2020.

By adjusting CryoSat-2’s orbit to synchronize with ICESat-2, ESA can collect radar and laser data from the same area almost simultaneously.

This arrangement allows scientists to measure snow depth from space, providing unprecedented precision for tracking sea and land ice thickness.

ESA CryoSat mission manager Tommaso Parrinello expressed optimism about the impact of the event:

“CryoSat has provided a valuable platform for understanding Earth’s ice cover over the past 14 years, but by aligning our data with ICESat-2, we are opening up new avenues for precision and insight.

“This collaboration represents an exciting step, not only in terms of technology, but also in how we can better serve the scientists and policymakers who rely on our data to understand and mitigate climate impacts.”

Shorsten Markus, project scientist for NASA’s ICESat-2 mission, said: “It’s great to see that the sister mission data provide a consistent picture of the changes taking place in Greenland.

“Understanding the similarities and differences between radar and lidar ice sheet height measurements allows us to take full advantage of the complementarity of these satellite missions.

“Studies like this are critical to putting together a comprehensive time series of ICESat, CryoSat-2, ICESat-2, and future CRISTAL missions.”

ESA’s CryoSat-2 continues to play an important role in our understanding of climate-related changes in polar ice, working with NASA’s ICESat-2 to provide reliable, accurate data on ice sheet changes.

Together, these missions represent an important step forward in monitoring polar ice loss and preparing for its global consequences.

CPOM is a partnership of six universities and the British Antarctic Survey (BAS), based at Northumbria University and funded primarily by the National Environmental Research Council (NERC) to provide national observations and observations of processes occurring in the polar regions. Modeling capabilities.

CPOM uses satellite observations to monitor changes in the polar regions and numerical models to better predict future ice and ocean evolution.

By providing the scientific community with long-term capabilities and leading international assessments, CPOM helps global policymakers plan for the impacts of climate change and sea level rise.