THINNING HISTORY OF THE FOUNDATION-THIEL TROUGH ICE STREAM: A KEY CONTROL ON DEGLACIATION OF THE WEST ANTARCTIC ICE SHEET, WEDDELL SEA EMBAYMENT

南极冰盖是地球上最大的冰盖，任何不稳定都可能主导全球海平面的变化。因此，我们需要冰盖模型来对未来的变化作出更可靠、更有力的预测。应对这一挑战的一个问题是缺乏用于初始化和校准模型的过去冰川消融数据。这个问题在威德尔海海湾尤其严重，特别是在它的东部，那里的蒂尔海槽是南极西部冰盖（WAIS）的主要排水通道，它的南部延伸可能是未来不稳定的潜在地点。我们在这里提出了一个综合的实地和建模研究，该研究将利用来自不同学科的几个新兴实地数据集的机会，从关键位置收集新数据，并使用复杂的冰盖模型调查过去和未来的冰川消融。为了了解冰变薄和沿冰槽退缩的历史，我们将采用一种测量尺的方法来测量基础冰流，这是在最后一个冰河时期占据冰槽的冰流的上游延伸。我们将通过地貌学和暴露年龄测定来确定这个基金会-蒂尔槽冰流的变薄历史：这些技术已被有效地用于了解南极洲其他地区的冰盖历史。为了理解我们测量的冰流历史的强迫机制，我们将在整个WAIS上应用一个3D模型，并结合最新的重要理论进展。我们将继续使用该模型来预测WAIS未来可能的稳定性，包括长期轨迹和对气候变化情景的任何响应，特别是它是否会沿着基金会-蒂尔海槽进一步退缩。

The Antarctic ice sheet is the largest on earth and any instability is likely to dominate global sea level change. We therefore require models of the ice sheet to make more reliable and robust predictions of future change. One problem in meeting this challenge is the lack of past data on deglaciation with which to initialize and calibrate the models. This problem has been particularly acute in the Weddell Sea embayment and in particular its eastern part where the Foundation - Thiel Trough has been a principal drainage route for the West Antarctic Ice Sheet (WAIS), and its southern extension may be a potential location for future instability. We propose here an integrated field and modelling study that will exploit the opportunity of several emerging field datasets from a range of different disciplines, collect fresh data from a crucial location, and investigate past and future deglaciation using sophisticated ice sheet models. To understand the history of ice thinning and retreat along the trough we will adopt a dipstick approach to survey the Foundation Ice Stream, an upstream extension of the ice stream that occupied the trough during the last ice age. We will determine the thinning history of this Foundation-Thiel Trough Ice Stream from geomorphology and exposure age dating: techniques that have been used effectively to provide insight into ice sheet history in other regions of Antarctica. We will apply a 3D model - incorporating significant recent theoretical advances - to the whole of the WAIS in order to understand the forcing mechanisms for the ice stream history we measure. We will go on to use this model to predict the likely future stability of the WAIS in terms of both long-term trajectory and any response to climate change scenarios, and in particular whether it will retreat further along the Foundation-Thiel Trough.