Models and observational constraints for fast ice flow and marine ice sheet dynamics

快速冰流和海洋冰盖动力学的模型和观测约束

• 批准号: 357193-2008
• 负责人: Schoof, Christian
• 金额: $ 1.46万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=459839
• 关键词: Models; observational; constraints; fast; ice

The ice sheets of Greenland and West Antarctica contain sufficient fresh water to raise global sea levels by about 13 metres. At present, there are no reliable predictions of how fast these ice sheets may shrink under projected climate change, and the future rate of sea level rise cannot be forecast accurately. Better predictions of ice sheet behaviour will require a number of physical processes to be represented more accurately in numerical models. Ice sheets do not flow evenly, but contain channels of fast flow known as ice streams. How these ice streams form, evolve and ultimately shut down again is only partially understood, and much of the physics involved is not represented in currebt ice sheet models. Similarly, the physics that controls the evolution of the edges of ice sheets (and hence their horizontal extent) is only partially understood. In particular, the edges of the Greenland and Antarctic ice sheets are defined in many places by the location where ice begins to float and forms an ice shelf. The rate at which ice flows through these junctions between ice sheets and ice shelves cannot be predicted accurately by present models, hampering efforts to estimate future sea level changes. The proposed research program will target these weaknesses in current ice sheet models by addressing the fundamental physics involved in ice stream flow and in the evolution of the margins of ice sheets. The research program will take a two-pronged approach, using sophisticated modern mathematical methods in conjunction with data from a new field program to derive improved representation of ice sheet physics for use in numerical simulations.

格陵兰岛和南极洲西部的冰盖含有足够的淡水，可以使全球海平面上升约13米。目前，还没有可靠的预测，这些冰盖在预计的气候变化下会以多快的速度缩小，未来海平面上升的速度也无法准确预测。要更好地预测冰盖的行为，就需要在数值模型中更准确地表示一些物理过程。冰盖的流动并不均匀，但包含了被称为冰流的快速流动通道。这些冰流是如何形成、演变并最终再次关闭的，人们只了解了一部分，而且所涉及的大部分物理学原理在当前的冰盖模型中也没有体现出来。同样，控制冰盖边缘演变的物理学（以及它们的水平范围）也只是部分了解。特别是，格陵兰和南极冰盖的边缘在许多地方都是由冰开始漂浮并形成冰架的位置来定义的。目前的模型无法准确预测冰流过冰盖和冰架之间的这些连接处的速度，这阻碍了估计未来海平面变化的努力。拟议的研究计划将通过解决冰流流动和冰盖边缘演变所涉及的基本物理学问题，针对当前冰盖模型中的这些弱点。该研究计划将采取双管齐下的方法，使用先进的现代数学方法，结合新的现场项目的数据，以获得用于数值模拟的冰盖物理学的改进表示。