Gräff Dominik, Lipovsky Bradley Paul, Vieli Andreas, Dachauer Armin, Jackson Rebecca, Farinotti Daniel, Schmale Julia, Ampuero Jean-Paul, Berg Eric, Dannowski Anke, Kneib-Walter Andrea, Köpfli Manuela, Kopp Heidrun, van der Loo Enrico, Mata Flores Daniel, Mercerat Diego, Moser Raphael, Sladen Anthony, Walter Fabian, Wasser Diego, Welty Ethan, Wetter Selina, Williams Ethan F
Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA.
Laboratory for Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland.
Nature. 2025 Aug;644(8076):404-412. doi: 10.1038/s41586-025-09347-7. Epub 2025 Aug 13.
Interactions between melting ice and a warming ocean drive the present-day retreat of tidewater glaciers of Greenland, with consequences for both sea level rise and the global climate system. Controlling glacier frontal ablation, these ice-ocean interactions involve chains of small-scale processes that link glacier calving-the detachment of icebergs-and submarine melt to the broader fjord dynamics. However, understanding these processes remains limited, in large part due to the challenge of making targeted observations in hazardous environments near calving fronts with sufficient temporal and spatial resolution. Here we show that iceberg calving can act as a submarine melt amplifier through excitation of transient internal waves. Our observations are based on front-proximal submarine fibre sensing of the iceberg calving process chain. In this chain, calving initiates with persistent ice fracturing that coalesces into iceberg detachment, which in turn excites local tsunamis, internal gravity waves and transient currents at the ice front before the icebergs eventually decay into fragments. Our observations show previously unknown pathways in which tidewater glaciers interact with a warming ocean and help close the ice front ablation budget, which current models struggle to do. These insights provide new process-scale understanding pertinent to retreating tidewater glaciers around the globe.
融化的冰与变暖的海洋之间的相互作用推动了格陵兰岛当今潮水冰川的退缩，这对海平面上升和全球气候系统都产生了影响。这些冰 - 海相互作用控制着冰川前端消融，涉及一系列小规模过程，这些过程将冰川崩解（冰山脱离）和海底融化与更广泛的峡湾动力学联系起来。然而，对这些过程的理解仍然有限，很大程度上是因为在靠近崩解前沿的危险环境中进行具有足够时间和空间分辨率的定向观测面临挑战。在这里，我们表明冰山崩解可以通过激发瞬态内波起到海底融化放大器的作用。我们的观测基于对冰山崩解过程链的前端近端海底光纤传感。在这个过程链中，崩解始于持续的冰破裂，这些破裂合并成冰山脱离，冰山脱离继而在冰前沿激发局部海啸、内重力波和瞬态电流，最终冰山分解成碎片。我们的观测揭示了潮水冰川与变暖海洋相互作用的前所未知的途径，并有助于闭合当前模型难以做到的冰前沿消融收支。这些见解为全球正在退缩的潮水冰川提供了新的过程尺度理解。
