A unique satellite experiment has provided scientists with a rare opportunity to compare Antarctic ice movement across a span of three decades. By temporarily flying the European Space Agency's Sentinel-1C and Sentinel-1D radar satellites in close formation, researchers recreated the one-day observation interval first achieved by the ERS-1 and ERS-2 satellites in 1995. The result is an unusually direct comparison of how parts of Antarctica have evolved over the last 30 years.
The tandem configuration allowed the satellites to collect radar images of the same Antarctic regions just 24 hours apart. This short interval is especially valuable for measuring glacier movement and identifying shifts in grounding lines, the critical zones where grounded ice begins to float and form ice shelves. These measurements help scientists understand how ice sheets respond to a warming climate and improve projections of future sea-level rise.
One striking example comes from the Scar Inlet Ice Shelf, the remaining southern section of the former Larsen B Ice Shelf. Comparisons between 1995 and 2026 radar interferograms reveal major fractures and rifts that were absent three decades ago. Scientists say the weakening of this ice shelf has contributed to faster glacier flow and increased ice discharge into the ocean.
The observations also captured the fast-moving Evans Ice Stream in West Antarctica. Because the ice stream moves several metres each day, the one-day radar repeat cycle produced a much clearer picture of ice velocity than conventional six-day observations, enabling more precise measurements of glacier dynamics.
While this is not Belgian-led field research, the story highlights the value of Belgium's investment in Earth observation through the Belgian Science Policy Office (BELSPO) and its support for European space programmes. Satellite systems can monitor vast and remote areas of Antarctica that are impossible to measure from research stations alone, providing continent-scale insights into changes that are reshaping the ice sheet.