近日，英国兰卡斯特大学Malcolm McMillan团队研究了格陵兰冰盖表面冰下洪水的爆发。2025年7月30日，《自然—地球科学》杂志发表了这一成果。
随着地球气候变暖，格陵兰冰盖表面融化加剧，海平面上升速度加快。观测和理论表明，冰盖表面产生的融水可以排到冰盖床上，在那里相对畅通无阻地流入海洋。这种对冰盖内部和冰盖下水运动的理解，为以预测冰盖变化为主题的理论模型奠定了基础。
研究组提出了格陵兰岛融水排水的破坏性模式的证据。通过多个卫星图像，他们发现，一股9000万立方米的冰下洪水从河床向上冲，破坏了冰盖，冲破了地表。这一现象是由一个冰下湖泊的快速排水引发的，并发生在一个预计冰床会冻结的地区。由此产生的洪水引发了下游海洋冰川的快速减速。
该观测揭示了冰盖表面和基础水文系统之间复杂的双向耦合，并表明极端水文强迫可能发生在预测的冷基冰区域。这些过程可以影响冰盖的动力学和结构完整性，但目前在冰盖模型中没有考虑到。
附：英文原文
Title: Outburst of a subglacial flood from the surface of the Greenland Ice Sheet
Author: Bowling, Jade S., McMillan, Malcolm, Leeson, Amber A., Livingstone, Stephen J., Sole, Andrew J., Ng, Felix S. L., Karlsson, Nanna B., Nienow, Peter, Boxall, Karla, Nol, Brice, van den Broeke, Michiel R., Slater, Thomas, Maddalena, Jennifer, Sandberg Srensen, Louise, Simonsen, Sebastian B., Mouginot, Jrmie, Millan, Romain, Melling, Laura, Taylor, Liam, Humbert, Angelika
Issue&Volume: 2025-07-30
Abstract: As Earth’s climate warms, surface melting of the Greenland Ice Sheet has intensified, increasing rates of sea-level rise. Observations and theory indicate that meltwater generated at the ice sheet surface can drain to its bed, where it flows relatively unhindered to the ocean. This understanding of water movement within and beneath ice sheets underpins the theoretical models that are used to make projections of ice sheet change. Here we present evidence of a destructive mode of meltwater drainage in Greenland. Using multiple satellite sources, we show that a 90-million-cubic-metre subglacial flood forced its way upwards from the bed, fracturing the ice sheet, and bursting through the surface. This phenomenon was triggered by the rapid drainage of a subglacial lake and occurred in a region where the ice bed was predicted to be frozen. The resulting flood caused a rapid deceleration of the downstream marine-terminating glacier. Our observations reveal a complex, bi-directional coupling between the ice sheet’s surface and basal hydrological systems and demonstrate that extreme hydrological forcing may occur in regions of predicted cold-based ice. Such processes can impact the ice sheet’s dynamics and structural integrity but are not currently considered in ice sheet models.
DOI: 10.1038/s41561-025-01746-9
Source: https://www.nature.com/articles/s41561-025-01746-9