据了解，来自南大洋的温暖海水对南极冰川的演变有主导影响，反过来又对海平面上升产生影响。
研究利用2023年3-6月收集的来自ICEYE星座的日重复卫星，合成孔径雷达干涉测量数据的连续时间序列，在西南极洲斯韦茨冰川主干区记录了一个冰搁浅区，即海洋中搁浅冰与浮冰之间过渡边界的潮汐控制迁移区域，这是海平面上升的一个重要因素，其冰量相当于全球海平面上升0.6 m。
在斯韦茨冰川的中部，冰面带宽6km，底部斜坡较浅，其两侧宽2km，底部斜坡较陡。该研究还探测到了不规则的海水注入，厚度为5-10cm，在涨潮时向上游延伸6km，位于阻碍冰川退缩的基岩山脊以外的河床凹陷处。
海水侵入与GlaDS冰下水模型预测的区域相吻合，在低压冰下水通道之间形成高压分布式冰下水文系统。加压的海水侵入将导致数公里范围内的地面冰剧烈融化，使冰川更容易受到海洋变暖的影响，并增加冰质量损失的预测。地面冰层下一公里宽的大范围海水侵入可能是冰盖质量快速、过去和现在变化与冰盖模型所复制的较慢变化之间缺失的一环。
附：英文原文
Title: Widespread seawater intrusions beneath the grounded ice of Thwaites Glacier, West Antarctica
Author: Rignot, Eric, Ciracì, Enrico, Scheuchl, Bernd, Tolpekin, Valentyn, Wollersheim, Michael, Dow, Christine
Issue&Volume: 2024-5-20
Abstract: Warm water from the Southern Ocean has a dominant impact on the evolution of Antarctic glaciers and in turn on their contribution to sea level rise. Using a continuous time series of daily-repeat satellite synthetic-aperture radar interferometry data from the ICEYE constellation collected in March–June 2023, we document an ice grounding zone, or region of tidally controlled migration of the transition boundary between grounded ice and ice afloat in the ocean, at the main trunk of Thwaites Glacier, West Antarctica, a strong contributor to sea level rise with an ice volume equivalent to a 0.6-m global sea level rise. The ice grounding zone is 6 km wide in the central part of Thwaites with shallow bed slopes, and 2 km wide along its flanks with steep basal slopes. We additionally detect irregular seawater intrusions, 5 to 10 cm in thickness, extending another 6 km upstream, at high tide, in a bed depression located beyond a bedrock ridge that impedes the glacier retreat. Seawater intrusions align well with regions predicted by the GlaDS subglacial water model to host a high-pressure distributed subglacial hydrology system in between lower-pressure subglacial channels. Pressurized seawater intrusions will induce vigorous melt of grounded ice over kilometers, making the glacier more vulnerable to ocean warming, and increasing the projections of ice mass loss. Kilometer-wide, widespread seawater intrusion beneath grounded ice may be the missing link between the rapid, past, and present changes in ice sheet mass and the slower changes replicated by ice sheet models.
DOI: 10.1073/pnas.2404766121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2404766121