The two satellites employ distinct technologies to measure surface height. CryoSat uses radar altimetry, capable of penetrating clouds and ice surfaces, while ICESat-2 uses laser altimetry, which provides surface-level readings unaffected by subsurface features but is hindered by cloud cover. Together, these complementary systems offer an unparalleled perspective on polar ice changes.
A study by the UK Centre for Polar Observation and Modelling (CPOM), published in Geophysical Research Letters, found that measurements of the Greenland Ice Sheet's elevation changes from CryoSat and ICESat-2 align within 3%. This alignment validates their combined use to enhance the accuracy of ice loss estimates and provides redundancy in monitoring should one mission experience a failure.
Between 2010 and 2023, the Greenland Ice Sheet thinned by an average of 1.2 meters, with the ablation zone, where summer melting exceeds winter snowfall, experiencing a much higher average thinning of 6.4 meters. At its most extreme, outlet glaciers like Sermeq Kujalleq (Jakobshavn Isbrae) and Zachariae Isstrom recorded thinning peaks of 67 and 75 meters, respectively. Over the 13-year study period, the ice sheet lost 2,347 cubic kilometers of ice, equivalent to the volume of Africa's Lake Victoria. Extreme melting events in 2012 and 2019 alone accounted for more than 400 cubic kilometers of loss each year.
This melting significantly impacts global ocean circulation and weather systems, with cascading effects on ecosystems and communities worldwide. Access to precise, real-time data is vital for crafting effective responses to these challenges.
Lead author and CPOM researcher Nitin Ravinder highlighted the importance of the findings: "We are very excited to have discovered that CryoSat and ICESat-2 are in such close agreement. Their complementary nature provides a strong motivation to combine the data sets to produce improved estimates of ice sheet volume and mass changes. As ice sheet mass loss is a key contributor to global sea level rise, this is incredibly useful for the scientific community and policymakers."
The study utilized four years of data from both missions, including those gathered during the Cryo2ice campaign, a collaborative effort initiated in 2020. By aligning CryoSat's orbit with ICESat-2's, ESA enabled near-simultaneous collection of radar and laser measurements, facilitating snow depth assessments with unprecedented precision.
Tommaso Parrinello, CryoSat Mission Manager at ESA, emphasized the significance of the collaboration: "CryoSat has provided an invaluable platform for understanding our planet's ice coverage over the past 14 years, but by aligning our data with ICESat-2, we've opened new avenues for precision and insight. This collaboration represents an exciting step forward, not just in terms of technology but in how we can better serve scientists and policymakers who rely on our data to understand and mitigate climate impacts."
NASA's ICESat-2 project scientist Thorsten Markus added: "It is great to see that the data from 'sister missions' are providing a consistent picture of the changes going on in Greenland. Understanding the similarities and differences between radar and lidar ice sheet height measurements allow us to fully exploit the complementary nature of those satellite missions. Studies like this are critical to put a comprehensive time series of the ICESat, CryoSat-2, ICESat-2, and, in the future, CRISTAL missions together."
ESA's CryoSat and NASA's ICESat-2 missions continue to lead advancements in monitoring polar ice loss, providing critical data for addressing the global impacts of climate change.
Related Links
CryoSat at ESA
Beyond the Ice Age
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