Theory and Models of Ice Sheet Surface Melting Instabilities in the Past and Future

过去和未来冰盖表面融化不稳定性的理论和模型

基本信息

批准号：
1735715
负责人：
Victor Tsai
金额：
$ 22.48万
依托单位：
California Institute of Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1735715&HistoricalAwards=false
关键词：
Theory Models Ice Sheet Surface

项目摘要

Sudden accelerations in melting at the junction of merged ice sheets are thought to have caused some of the most rapid sea level rise events in history. Existing theories of ice sheet surface melting do not consider such regions and are not able to reproduce these sudden accelerations in ice sheet surface melting. To predict the likelihood of such rapid sea level rise events in the future, it is important to understand why such events happened in the past. This project will develop a new mathematical theory for ice sheet surface melting instabilities within ice saddle regions. It will compare the predictions of this theory to complex ice sheet models and perform more realistic simulations to determine whether the Greenland Ice Sheet may undergo such a sudden acceleration in melting under future warming. This project includes a number of broader impacts. Sea level rise threatens life and infrastructure along coastlines throughout the world. Accurate projections of potential periods of rapid future sea level rise will inform strategic decision-making about mitigation strategies and infrastructure design. The project will also contribute to STEM workforce development by supporting the training of a post-doctoral associate and a graduate student. A web-based application employing the simple model developed during this project will be produced as an effective outreach tool for explaining ice sheet dynamics to the public.The primary goal of this project is to develop a theory that explains the occurrence of deglacial meltwater pulses from land-based ice sheets under a warming climate. A new variant on the classical single-dome ice sheet model that relaxes previous assumptions and considers an ice-saddle geometry will be produced. This new ice-saddle model will be numerically tested to determine the conditions under which it produces a significant deglacial meltwater pulse. Asymptotic mathematical techniques, such as multiple time scales analysis, will be used to derive functional expressions for the magnitude and speed of meltwater pulses predicted by these models. The utility of the ice-saddle theory in explaining reality will be evaluated by comparing it to more complex ice sheet models and proxy records of sea level rise during meltwater pulses. Finally, multi-millennial simulations of the Greenland Ice Sheet under different scenarios of future climate change will be developed.

据认为，在合并冰盖结合处融化的突然加速造成了历史上一些最快的海平面上升事件。现有的冰盖表面熔化理论不考虑此类区域，也无法在冰层表面熔化中重现这些突然的加速度。为了预测未来如此快速的海平面上升事件的可能性，重要的是要了解为什么这种事件发生在过去。该项目将开发出一种新的数学理论，用于冰鞍区域内的冰盖表面熔化的不稳定性。它将将该理论的预测与复杂的冰盖模型进行比较，并执行更逼真的模拟，以确定格陵兰冰盖是否会在未来变暖的情况下熔化会突然加速。该项目包括许多更广泛的影响。海平面上升威胁着世界各地海岸线的生活和基础设施。对快速未来海平面上升的潜在潜在时期的准确预测将为缓解策略和基础设施设计的战略决策提供信息。该项目还将通过支持博士后同学和研究生的培训来为STEM劳动力发展做出贡献。基于Web的应用程序采用该项目期间开发的简单模型的应用程序将被作为一种有效的外展工具，用于向公众解释冰盖动态。该项目的主要目标是开发一种理论，该理论解释了从冰川冰川脉动的发生。在温暖的气候下，陆基冰盖。经典的单型冰盖模型上的一种新变体，它会放松先前的假设并考虑产生冰原几何形状。这种新的冰垫模型将经过数值测试，以确定其产生明显的脱气融化脉冲的条件。渐近数学技术（例如多个时间尺度分析）将用于得出这些模型预测的融合水脉冲的幅度和速度的功能表达式。冰垫理论在解释现实中的效用将通过将冰盖模型和融化过程中海平面上升的代理记录进行比较来评估现实。最后，将在未来气候变化的不同情况下对格陵兰冰盖进行多千年模拟。