NSF-NERC: Ground Geophysics Survey of Thwaites Glacier

该项目有助于美国国家科学基金会（NSF）和英国联合发起的联合倡议。自然环境研究理事会（NERC）将大幅改善对南极洲西部Thwaites冰川造成的冰损失和海平面上升的十年期和长期预测。 海平面迅速上升对基础设施造成的全球成本（例如，房屋、道路、农场、港口）可能很大。 海平面上升的一个可能的水源是南极西部冰盖，特别是思韦茨冰川。 冰盖和冰川含有大量的水（以冰的形式），这些水不断地流入海洋，并不断地被降雪（从海洋蒸发的水）补充。 如果斯韦茨冰川在未来几十年内流失到海洋中的冰量远远大于降雪量，那么世界上所有海洋的海平面都将上升，可能高达1米（约3英尺）。 为了估计这种灾难性情景的可能性，我们需要更好地了解Thwaites冰川滑动的表面。 如果我们能更好地描述该层（“是平滑？很难吗？软不软？很难吗？“），那么斯韦茨冰川的计算机模型将得到很大的改进，我们可以更好地预测斯韦茨冰川将流入海洋的冰量。该项目的目标是了解基础条件是否允许斯韦茨冰川接地线快速退缩，或者退缩是否可能在其当前接地线附近重新稳定下来。这些目标将通过使用专门的冰流建模来实现，以指导两个季节的有针对性的实地调查和实验，并测量最重要的未知量并将其纳入模型。数值模型将被用来产生假设的基础条件，是通过地球物理调查和项目的未来行为的思韦茨冰川同化后的数据进行测试。地球物理方法包括地震、雷达、重力和电学勘测，这些方法结合在一起，可以更全面地描述海床的特征。 我们将在冰川不同部分的代表性区域进行实地调查，包括冰川边缘、接地线附近以及冰川中心轴线沿着的集水区。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project contributes to the joint initiative launched by the U.S. National Science Foundation (NSF) and the U.K. Natural Environment Research Council (NERC) to substantially improve decadal and longer-term projections of ice loss and sea-level rise originating from Thwaites Glacier in West Antarctica. Global costs of rapid sea-level rise to infrastructure (e.g., houses, roads, farms, ports) are likely to be large. A possible source of water for sea-level rise is the West Antarctic Ice Sheet, and Thwaites Glacier in particular. Ice sheets and glaciers contain vast quantities of water (in the form of ice) that is continually shed to the ocean, and continually replenished by snowfall (from water that evaporates from the oceans). If the amount of ice that Thwaites Glacier loses to the ocean over the next decades is much greater than the amount it receives as snowfall, then sea level in all the world's oceans would rise, possibly as much as a meter (approximately 3 feet). In order to estimate how likely such a catastrophic scenario would be, we need to better understand the surface over which Thwaites Glacier slides. If we can better characterize that layer ("is to smooth? Is it rough? Is it soft? Is it hard?"), then computer models of Thwaites would be much improved and we can make better projections of the amount of ice that Thwaites Glacier would shed to the ocean.The objectives of the project are to learn whether basal conditions allow for rapid retreat of the Thwaites Glacier grounding line or whether retreat may re-stabilize near its current grounding line. These objectives will be achieved by using dedicated ice-flow modeling to guide targeted field surveys and experiments over two seasons, and to measure the most important unknown quantities and incorporate them into the models. Numerical models will be used to generate hypotheses for basal conditions that are testable through geophysical surveys and to project future behavior of Thwaites Glacier after assimilating the resulting data. The geophysical methods include seismic, radar, gravity, and electrical surveys that together will allow for a fuller characterization of the bed. We will conduct field surveys in areas representative of different parts of the glacier, including across the margins, near the grounding line, and along the central axis of the glacier into its catchment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.