QUoRUM: QUantifying and Reducing Uncertainty in Multi-Decadal Projection of Ice Sheet-Sea Level Contribution

西南极冰盖包含的冰足以导致海平面上升3.3米。仅阿蒙森海区的冰流就可能导致海平面上升1.2米，其变薄的速度比地球上任何其他地区都快，并有可能因内陆加深的基岩而迅速坍塌。利用新的逆模型、综合冰盖模型和遥感的组合，我们将：1)估计关键阿蒙森扇区的当前状态2)预测其未来行为3)量化这些估计和预测的不确定性。对冰盖退缩的物理学有定性的了解，但详细的行为取决于大量不能直接测量的参数(例如，空间变化的基本牵引力和冰的硬度)。然而，数值冰盖模型现在已经发展到可以准确地表示一些相关的物理过程的点，例如接地线移动和冰盖对海洋强迫的响应。此外，卫星观测记录继续增长，为将这些新数据同化到模型中创造了机会。这种模式-数据合成可以确定关键的潜在和隐藏的物理参数，促进对未来冰盖对海平面的贡献的数据驱动的预测。然而，使用冰盖模式同化数据的技术仍处于早期阶段。相当数量的数据仍未使用，基本问题，如可靠预测所需的具体信息，仍未得到回答。此外，冰盖未来行为的模型模拟通常没有考虑到隐藏参数估计中固有的不确定性，这些参数可能会随着预测地平线的增长而增长。考虑到这些不确定性是至关重要的，以便能够对海平面上升保护和适应进行知情的风险和成本效益分析。在拟议的项目中，我们将开发一个基于模型的框架，该框架将有效地吸收阿蒙森部门的数据记录(图1)，提供关键物理量的估计和对未来行为的预测。至关重要的是，将为估计和预测提供不确定性的衡量标准。我们将进一步研究不同观测对我们的模型预测的影响和其中的不确定性，提供对未来观测活动有价值的信息。虽然选择阿蒙森地区作为重点是为了关键的相关性和及时性，但这一方法可以更普遍地适用于南极洲的其他地区或格陵兰。

The West Antarctic Ice Sheet contains enough ice to cause 3.3 meters of sea level rise. The ice streams of its Amundsen Sea sector, which alone could contribute up to 1.2 meters of sea level rise, are thinning faster than in any other region on earth, and have the potential for rapid collapse due to inland-deepening bedrock. Using a combination of novel inverse modelling, a comprehensive ice-sheet model, and remote sensing we will: 1) Estimate the present state of the critical Amundsen sector2) Predict its future behaviour3) Quantify the uncertainty of these estimates and predictions The physics of ice-sheet retreat is qualitatively understood, but the detailed behaviour is dependent upon a very large number of parameters that cannot be measured directly (e.g, spatially-varying basal traction and ice stiffness). However, numerical ice sheet models have now evolved to the point where a number of relevant physical processes, such as grounding line movement and ice-sheet response to ocean forcing, can be represented accurately. Moreover, the satellite-observational record continues to grow, creating opportunities for assimilation of this new data into models. Such a model-data synthesis can allow key underlying and hidden physical parameters to be determined, facilitating data-driven prediction of future ice-sheet contribution to sea levels.However, techniques for the assimilation of data using ice sheet models remain at an early stage. A considerable amount of data remains unused and fundamental questions, such as the specific information required for reliable predictions, remain unanswered. Moreover, model simulations of future behaviour of ice sheets generally do not account for the uncertainty inherent in estimates of hidden parameters, which can potentially grow with forecast horizons. Accounting for these uncertainties is vital so that informed risk and cost-benefit analyses of sea-level rise protection and adaptation can be carried out.In the proposed project we will develop a model-based framework which will efficiently assimilate the data record for the Amundsen sector (Fig. 1), providing estimates of key physical quantities, and predictions of future behaviour. Crucially, measures of uncertainty will be provided for the estimate and predictions. We will further study the impact that different observations have on our model predictions and uncertainty therein, providing information that will be of value to future observational campaigns. While the Amundsen region is chosen as a focus in the interest of critical relevance and timeliness, the methodology can be applied more generally in other regions of Antarctica, or Greenland.