A holistic model of outlet calving, dynamic acceleration and drawdown for the Greenland Ice Sheet

格陵兰冰盖出口崩解、动态加速和下降的整体模型

• 批准号: NE/G010595/1
• 负责人: Alun Hubbard
• 金额: $ 6.76万
• 依托单位: Aberystwyth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG010595%2F1
• 关键词: holistic; model; outlet; calving; dynamic

The body of scientific evidence for significant anthropogenic impacts on the global climate is growing and public concern underscores a need for better assessments of contemporary environmental changes in polar regions. The greatest store of fresh water in the northern hemisphere - equivalent to 7m of eustatic sea level rise - is held within the Greenland Ice Sheet (GIS), and yet its present and future contribution to sea level is poorly constrained (IPCC, 2007). Recent observations suggest that mass loss near the margin of the GIS is accelerating through a combination of increased surface melting (e.g. Steffen et al, 2004) and dynamic thinning (e.g. Rignot and Kanagaratnam, 2006). However, the key processes controlling interior drawdown have yet to be fully identified, and in consequence, are not incorporated in the ice-sheet models which form the basis of the IPCC sea level projections. This in part reflects the fact that the satellite data that has revealed the widespread speed-up of glaciers cannot be acquired at the temporal resolution needed to resolve the causal mechanisms. This project focuses on second and third largest outlet glaciers of western GIS in order to help understand the processes by which these glaciers increase their speed and lose ice to the ocean by means of iceberg calving. Calving is the process of mechanical fracture where ice breaks off from the edge of glaciers and floating ice shelves. It accounts for the majority of loss from the Antarctic and over 50% of that from the GIS. Calving is a very efficient mass-loss mechanism which provides a rapid connection between the ice stored on land and the ocean where it is turned into sea level rise. Despite its fundamental importance, our understanding of the controls on iceberg calving and the associated process of dynamic drawdown are poorly understood and the present generation of coupled ice sheet models (ISMs) do not simulate these processes at all which severely handicaps their predictive ability. We aim to collect detailed oceanic, climatic, geodetic and geophysical datasets at two outlet glaciers which will enable us to: 1) investigate the main processes and linkages controlling iceberg calving and its effect on upstream glacier flow and thinning, and, 2) to use this data to refine a new process-based calving/flow dynamics criterion that can be easily included within models coupled to simulate the future climate and polar ice cover and its contribution on rising sea levels.

关于人类活动对全球气候产生重大影响的科学证据越来越多，公众的关切突出表明，需要更好地评估极地地区的当代环境变化。北方最大的淡水储存-相当于海平面上升7米-在格陵兰冰盖内，但其目前和未来对海平面的贡献受到很大限制（IPCC，2007）。最近的观测表明，由于表面融化增加（如Steffen等人，2004年）和动态变薄（如Rignot和Kanagaratnam，2006年），地理信息系统边缘附近的质量损失正在加速。然而，控制内部水位下降的关键过程尚未完全确定，因此，没有纳入冰盖模型，而冰盖模型是气专委海平面预测的基础。这在一定程度上反映了这样一个事实，即无法以解决因果机制所需的时间分辨率获得揭示冰川普遍加速的卫星数据。该项目的重点是地理信息系统西部第二和第三大出口冰川，以帮助了解这些冰川通过冰山崩解加快速度并将冰流失到海洋的过程。冰裂是一种机械断裂的过程，冰从冰川和浮冰架的边缘断裂。它占南极损失的大部分，占GIS损失的50%以上。崩解是一种非常有效的质量损失机制，它提供了陆地上储存的冰与海洋之间的快速连接，在那里它变成海平面上升。尽管其根本的重要性，我们的理解的控制冰山崩解和相关的过程中的动态下降的了解甚少，目前这一代的耦合冰盖模型（ISM）不模拟这些过程中，严重妨碍了他们的预测能力。我们的目标是在两个出口冰川收集详细的海洋，气候，大地测量和地球物理数据集，这将使我们能够：1）调查控制冰山崩解的主要过程和联系及其对上游冰川流动和变薄的影响，2）使用这些数据来完善新的基于过程的产犊/流动动力学标准，可以很容易地包括在耦合模型，以模拟未来的气候和极地冰盖及其对海平面上升的贡献。

项目成果

Persistent flow acceleration within the interior of the Greenland ice sheet

• DOI: 10.1002/2013gl058933
• 发表时间: 2014-02-16
• 期刊: GEOPHYSICAL RESEARCH LETTERS
• 影响因子: 5.2
• 作者: Doyle, Samuel H.;Hubbard, Alun;Hubbard, Bryn
• 通讯作者: Hubbard, Bryn

Cascading lake drainage on the Greenland Ice Sheet triggered by tensile shock and fracture.

• DOI: 10.1038/s41467-018-03420-8
• 发表时间: 2018-03-14
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Christoffersen P;Bougamont M;Hubbard A;Doyle SH;Grigsby S;Pettersson R
• 通讯作者: Pettersson R

Ice tectonic deformation during the rapid in situ drainage of a supraglacial lake on the Greenland Ice Sheet

• DOI: 10.5194/tc-7-129-2013
• 发表时间: 2013-01-01
• 期刊: CRYOSPHERE
• 影响因子: 5.2
• 作者: Doyle, S. H.;Hubbard, A. L.;Box, J. E.
• 通讯作者: Box, J. E.

Seasonal velocities of eight major marine-terminating outlet glaciers of the Greenland ice sheet from continuous in situ GPS instruments

来自连续原位 GPS 仪器的格陵兰冰盖八个主要海洋终止出口冰川的季节速度

• DOI: 10.5194/essdd-6-27-2013
• 发表时间: 2013
• 作者: Ahlstrøm A

Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

• DOI: 10.5194/tc-8-1457-2014
• 发表时间: 2014-01-01
• 期刊: CRYOSPHERE
• 影响因子: 5.2
• 作者: Chauche, N.;Hubbard, A.;Patton, H.
• 通讯作者: Patton, H.