Assessing the sensitivity of major East Antarctic outlet glaciers to recent and future changes in the ocean-climate system

评估主要东南极出口冰川对海洋气候系统近期和未来变化的敏感性

基本信息

批准号：
NE/R000719/1
负责人：
Hilmar Gudmundsson
金额：
$ 38.74万
依托单位：
Northumbria University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR000719%2F1
关键词：
Assessing sensitivity major East Antarctic

项目摘要

The Earth's atmosphere and oceans are warming as a result of increased concentrations of greenhouse gases. Glaciers melt when the Earth warms and water that was stored as ice on land runs off into the ocean and increases sea-level. Over the last few decades, measurements have shown that sea-level is increasing by around 3 millimetres per year, and that this is due to the expansion of the warmer ocean water and the runoff from glaciers. In the 20th century, the sea-level contribution from melting ice was dominated by small mountain glaciers and ice caps, but it is now known that the vast ice sheets in Greenland and Antarctica are contributing an equally large amount to sea level and that their contribution is accelerating. One of the main ways in which ice sheets contribute to sea-level (especially in Antarctica, but also in Greenland) is through rapidly-flowing outlet glaciers that transfer ice from the interior to the margins, where it breaks off as icebergs. Recent measurements, mostly using observations from satellites, have shown that many outlet glaciers are thinning and retreating and, in some cases, their flow is also accelerating. This helps explain why their ice discharge is increasing. These changes in outlet glaciers are complex, but scientists think that they are caused by warmer ocean temperatures and, in some cases, by the landscapes underneath the outlet glaciers, especially if they flow through deep valleys that are below sea level and get deeper inland under the ice. The most dramatic changes have been observed in Greenland and West Antarctica, which store around 6 and 4 m of sea-level equivalent, respectively. Thus, unlike smaller mountain glaciers, changes in outlet glaciers could contribute several metres to global sea-level, possibly over quite short time-scales (just a few centuries according to some predictions). It is for this reason that a lot of research is aimed at monitoring outlet glaciers in Greenland and West Antarctica. Most of the ice in Antarctica is, however, stored in East Antarctica, which holds a sea-level equivalent of around 53 m. It is perhaps surprising, therefore, that there are so few measurements of outlet glaciers in the East Antarctic Ice Sheet (EAIS), but this is probably because it was traditionally thought to be much more stable than West Antarctica. Recently, however, evidence has been uncovered which indicates that parts of the EAIS, especially those parts that that overlie deep valleys and basins, might have retreated quite dramatically when climate was slightly warmer in the past. Moreover, observations of just one or two glaciers in these same regions indicates that they are also thinning and retreating, similar to those in Greenland and West Antarctica. Thus, there is a small but growing body of evidence suggesting that some parts of the EAIS might also be vulnerable to global warming. Unfortunately, we do not have enough observations to know exactly what is happening in different parts of East Antarctica and there is a large amount of uncertainty about whether its outlet glaciers are sensitive to changes in the ocean and/or atmosphere. This project has been designed to specifically address this uncertainty. We will use satellite measurements to determine recent changes on some of the largest and most important outlet glaciers from different regions of East Antarctica. This will tell us where the most dramatic changes have taken place and which areas are more stable. We will then use a computer model to see what kind of changes would take place if air or ocean temperatures increase in the future. This will tell us which glaciers are most sensitive and what their contribution to sea level might be over the next few centuries. Even where glaciers are currently stable, it is important to know by how much climate would need to change before they might react. This new knowledge is vitally important to help governments plan for future changes in sea-level.

由于温室气体浓度增加，地球的大气和海洋正在变暖。冰川融化时，当地球温暖和水储存时，随着冰上的冰上的冰层流入海洋并增加了海平面。在过去的几十年中，测量结果表明，海平面每年增加3毫米，这是由于较温暖的海水和冰川径流的扩大所致。在20世纪，熔融冰层的海平面贡献以小型山地冰川和冰盖为主，但现在众所周知，格陵兰和南极洲的巨大冰盖正在为海平面贡献很大的贡献，并且它们的贡献正在加速。冰盖有助于海平面的主要方式（尤其是在南极洲，也是格陵兰岛），是通过快速流动的出口冰川从内部转移到边缘的冰川出口冰川，在那里它像冰山一样破裂。最近的测量值（主要是使用卫星观测值）表明，许多出口冰川正在变薄和撤退，在某些情况下，它们的流量也在加速。这有助于解释为什么他们的冰出排放量增加。出口冰川的这些变化很复杂，但是科学家认为它们是由较高的海洋温度引起的，在某些情况下是由出口冰川下方的景观引起的，尤其是当它们经过海平面以下的深山谷并在冰下变得更深的内陆时。在格陵兰岛和南极西部，观察到最大的变化，分别存储了大约6和4 m的海平面等效物。因此，与较小的山地冰川不同，出口冰川的变化可能会为全球海平面贡献几米，这可能是在很短的时间尺度上（根据一些预测，只有几个世纪）。正是由于这个原因，许多研究旨在监测格陵兰岛和南极西部的出口冰川。但是，南极洲的大多数冰都存储在南极洲东部，其海平面相当于约53 m。因此，也许令人惊讶的是，南极冰盖（EAIS）的出口冰川的测量很少，但这可能是因为传统上认为它比东南极西部的稳定得多。然而，最近发现了证据，表明EAI的一部分，尤其是那些覆盖深山谷和盆地的部分，当气候在过去稍温暖时，可能已经很大程度上撤退了。此外，在这些区域中仅观察到一个或两个冰川，这表明它们也正在变薄和撤退，类似于格陵兰和南极西部的冰川。因此，有少量但越来越多的证据表明，EAI的某些部分也可能容易受到全球变暖的影响。不幸的是，我们没有足够的观察结果来确切知道南极洲东部不同地区正在发生的事情，并且对于其出口冰川是否对海洋和/或大气的变化敏感，存在很大的不确定性。该项目旨在专门解决这种不确定性。我们将使用卫星测量结果来确定南极不同地区最大，最重要的出口冰川的最新变化。这将告诉我们发生了最大的变化，哪些区域更稳定。然后，我们将使用计算机模型来查看如果未来的空气或海洋温度升高，会发生什么样的变化。这将告诉我们哪些冰川最敏感，并且在接下来的几个世纪中，它们对海平面的贡献可能是什么。即使冰川目前稳定，也必须通过对它们做出反应之前需要改变多少气候也很重要。这种新知识对于帮助政府计划未来的海平面变化至关重要。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Increased warm water intrusions could cause mass loss in East Antarctica within 200 years

增加的暖水入侵可能会在200年内导致东南极洲的质量损失

DOI：
10.21203/rs.3.rs-1558927/v1
发表时间：
2022
期刊：
影响因子：
0
作者：
Jordan J
通讯作者：
Jordan J

The predictive power of ice sheet models and the regional sensitivity of ice loss to basal sliding parameterisations: A case study of Pine Island and Thwaites Glaciers, West Antarctica

冰盖模型的预测能力以及冰损失对基底滑动参数化的区域敏感性：以西南极洲松岛和思韦茨冰川为例

DOI：
10.5194/tc-2022-109
发表时间：
2022
期刊：
影响因子：
0
作者：
Barnes J
通讯作者：
Barnes J

Increased warm water intrusions could cause mass loss in East Antarctica during the next 200 years.

DOI：
10.1038/s41467-023-37553-2
发表时间：
2023-04-01
期刊：
NATURE COMMUNICATIONS
影响因子：
16.6
作者：
Jordan, James R.;Miles, B. W. J.;Gudmundsson, G. H.;Jamieson, S. S. R.;Jenkins, A.;Stokes, C. R.
通讯作者：
Stokes, C. R.

Supplementary material to "Slowdown of Shirase Glacier caused by strengthening alongshore winds"

“沿岸风增强导致白濑冰川速度减缓”的补充材料