英国南极调查局Davis, Peter E. D.小组研究认为思韦茨冰川东部接地带基底融化受到抑制。2023年2月15日出版的《自然》发表了这项成果。

研究团队展示了从一个热水钻探的入口洞中获得的主题观测数据，思韦茨东部冰架(TEIS)的接地区以温暖和高度稳定的水柱为特征，其温度远远高于原地冰点。尽管有这些温暖的条件，但冰-海洋边界层的低流速和强密度分层积极地限制了热量向冰基的垂直混合，从而强烈抑制了基底融化。研究结果表明，用于生成海平面预测为主题的冰架底部融化的典型模型不能再现在这个至关重要的冰川下观测到的融化速率，快速且可能不稳定的接地线后退可能与相对温和的底部融化速率有关。

据介绍，思韦茨冰川是南极洲变化最快的冰-海洋系统之一。思韦茨冰川汇水区的大部分冰盖都建立在海平面以下的基岩上，基岩加深了内陆，使其容易遭受迅速而不可逆转的冰流失，这可能会使全球海平面上升半米多。冰损失的速度和程度，以及它是否不可逆转地继续下去，取决于海洋条件和思韦茨冰川第一次漂浮的地面区域内的基面融化所决定的，这两者在很大程度上都是未知的。

附：英文原文

Title: Suppressed basal melting in the eastern Thwaites Glacier grounding zone

Author: Davis, Peter E. D., Nicholls, Keith W., Holland, David M., Schmidt, Britney E., Washam, Peter, Riverman, Kiya L., Arthern, Robert J., Vakov, Irena, Eayrs, Clare, Smith, James A., Anker, Paul G. D., Mullen, Andrew D., Dichek, Daniel, Lawrence, Justin D., Meister, Matthew M., Clyne, Elisabeth, Basinski-Ferris, Aurora, Rignot, Eric, Queste, Bastien Y., Boehme, Lars, Heywood, Karen J., Anandakrishnan, Sridhar, Makinson, Keith

Issue&Volume: 2023-02-15

Abstract: Thwaites Glacier is one of the fastest-changing ice–ocean systems in Antarctica. Much of the ice sheet within the catchment of Thwaites Glacier is grounded below sea level on bedrock that deepens inland, making it susceptible to rapid and irreversible ice loss that could raise the global sea level by more than half a metre. The rate and extent of ice loss, and whether it proceeds irreversibly, are set by the ocean conditions and basal melting within the grounding-zone region where Thwaites Glacier first goes afloat, both of which are largely unknown. Here we show—using observations from a hot-water-drilled access hole—that the grounding zone of Thwaites Eastern Ice Shelf (TEIS) is characterized by a warm and highly stable water column with temperatures substantially higher than the in situ freezing point. Despite these warm conditions, low current speeds and strong density stratification in the ice–ocean boundary layer actively restrict the vertical mixing of heat towards the ice base, resulting in strongly suppressed basal melting. Our results demonstrate that the canonical model of ice-shelf basal melting used to generate sea-level projections cannot reproduce observed melt rates beneath this critically important glacier, and that rapid and possibly unstable grounding-line retreat may be associated with relatively modest basal melt rates.

DOI: 10.1038/s41586-022-05586-0

Source: https://www.nature.com/articles/s41586-022-05586-0