An improved 15-year record of ice sheet elevation from CryoSat-2 radar altimetry

Abstract

The Greenland and Antarctic ice sheets are major contributors to global sea level rise, and their rate of ice loss has increased fourfold in the past 30 years. Providing a near-continuous record of observations since the 1990s, satellite radar altimeters are well-suited to monitoring ice sheet evolution, and to contributing to quantifying and understanding the drivers of ice sheet change. Among these missions, CryoSat-2 carries an advanced Synthetic Aperture Radar (SAR) Interferometric Radar Altimeter (SIRAL) that allows for more accurate measurement of the surface height over complex topography, such as across the terrain of the ice sheet margins. The measurement accuracy depends critically on the Level-2 processing chain applied to convert the detected surface response to an elevation estimate. Here, we present and assess a new and improved 15-year record of ice sheet elevation and elevation change, derived from CryoSat-2 measurements acquired between 2010 and 2025. We validate this new dataset using ∼10,000 Airborne Topographic Mapper (ATM) observations and more than 3 million Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) measurements, and show that the new products agree more closely with these independent reference data than other available Level-2 products. Additionally, we compute rates of elevation change and compare these to equivalent ICESat-2 estimates between 2018 and 2024 and find close agreement in the spatially resolved signals of ice sheet imbalance; with median differences in the elevation rates of 0.01–0.02 m/yr, and 84% of assessed data agreeing to within 0.1 m/yr. Our new datasets provide an improved 15-year record of ice sheet evolution during a period of rapid climate change, which will benefit our understanding of the magnitude and drivers of contemporary ice sheet mass loss.