The role of atmosphere-ocean-ice interactions in ice loss from Pine Island and Thwaites Glaciers, West Antarctica

大气-海洋-冰相互作用在西南极洲松岛和思韦茨冰川冰损失中的作用

• 批准号: NE/H02333X/1
• 负责人: John Turner
• 金额: $ 63.91万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH02333X%2F1
• 关键词: role; atmosphere; ocean; ice; interactions

The West Antarctic Ice Sheet contains over 2 million cubic kilometres of ice, which if it all melting would raise sea level by over 3 metres. As part of the natural hydrological cycle of the ice sheet, ice flows down to the coast in a number of glaciers and is lost to the ocean as ice bergs. Snowfall across the Antarctic then replenishes the ice in the ice sheet. The two largest and fastest flowing West Antarctic outlet glaciers are the Pine Island Glacier and the Thwaites Glacier, which together drain about 10% of the West Antarctic ice sheet. In recent decades the Pine Island and Thwaites Glaciers have thinned and retreated at a remarkable rate, contributing nearly 10% of the observed rise in global sea level. Air temperatures on these glaciers are almost never above freezing, even during the summer months, so their retreat has not been a result of direct warming from the atmosphere. Instead, an increase of ocean temperature is thought to be responsible for the changes. The area of Pine Island Bay is susceptible to intrusions of relatively warm Circumpolar Deep Water that occurs across the floor of the continental shelves to the north of the region. It is known that the arrival of Circumpolar Deep Water to the area is affected by the weather systems over the ocean to the north of West Antarctica, and particularly to the depth and local of depressions. This research will shed light on why the Pine Island and Thwaites Glaciers have been retreating in recent decades and predict their evolution over the next century and produced improved predictions of their potential contribution to sea level rise. The links between weather patterns, ocean currents, melting under the glaciers and the retreat of the glaciers themselves are very complex and can only be understood by simulating them on computers. We will therefore develop new, detailed atmospheric, ocean and ice models to simulate the environment of the Southern Ocean north of the Pine Island bay. We have a great deal of meteorological data for the last 30 years and this will allow us to understand how changes in weather patterns have influenced the delivery of Circumpolar Deep Water to Pine Island Bay. We will therefore run our models for the period 1980 - 2010. However, satellite pictures of the area and information from the ocean floor of Pine Island bay collected by oceanographic equipment suggests that the glaciers have been retreating from at least the middle of the Twentieth Century. This could be a result of changes in the weather patterns during the last century, but in the remote Antarctic we have very few meteorological observations for this period. We will therefore reconstruct the weather patterns across this sector of the Southern Ocean during the Twentieth Century using the chemical signals locked into ice cores. The 21 nation International Trans Antarctic Scientific Expedition has collected many ice cores across West Antarctic and they will form the basis of our reconstruction. How the Pine Island Glacier and the Thwaites Glacier will change over the next century is an extremely important question because of the consequences for sea level rise. We will produce improved predictions of their change during the next century by using our knowledge of glacier retreat in terms of atmospheric circulation. We will use the predictions of atmospheric change across the ocean north of West Antarctica produced by the Intergovernmental Panel on Climate Change. Their predictions of atmospheric change for different increases of greenhouse gases will be used and will allow us to determine changes in Circumpolar Deep Water and therefore melt of the glaciers over the next century.

南极西部冰盖包含超过200万立方千米的冰，如果全部融化，将使海平面上升3米多。作为冰盖自然水文循环的一部分，冰以许多冰川的形式流向海岸，并以冰山的形式流入海洋。整个南极的降雪补充了冰盖中的冰。南极西部最大和流动最快的两个出口冰川是松岛冰川和斯韦茨冰川，它们加起来约占南极西部冰盖的10%。近几十年来，松岛冰川和思韦茨冰川以惊人的速度变薄和退缩，对观测到的全球海平面上升的贡献接近10%。这些冰川上的气温几乎从未超过冰点，即使是在夏季，因此它们的退缩并不是大气直接变暖的结果。相反，海洋温度的升高被认为是造成这些变化的原因。松岛湾地区很容易受到相对温暖的环极深水的入侵，这种深水发生在该地区北部的大陆架底部。众所周知，环极深水到达该地区受到西南极洲北部海洋上空天气系统的影响，特别是受到低气压的深度和局部影响。这项研究将揭示为什么松岛冰川和思韦茨冰川在近几十年来一直在退缩，并预测它们在下个世纪的演变，并对它们对海平面上升的潜在贡献做出更好的预测。天气模式、洋流、冰川下的融化和冰川本身的退缩之间的联系非常复杂，只能通过计算机模拟来理解。因此，我们将开发新的、详细的大气、海洋和冰模型来模拟松树岛湾以北的南大洋环境。我们有过去30年的大量气象数据，这将使我们了解天气模式的变化是如何影响环极深水向松岛湾的输送的。因此，我们将运行1980 - 2010年期间的模型。然而，该地区的卫星图片和海洋设备从松岛湾海底收集的信息表明，至少从20世纪中叶开始，冰川一直在退缩。这可能是上个世纪天气模式变化的结果，但在遥远的南极，我们对这一时期的气象观测很少。因此，我们将利用锁定在冰芯中的化学信号，重建20世纪南大洋这一区域的天气模式。21国国际跨南极科学考察队在南极西部收集了许多冰芯，它们将成为我们重建南极的基础。由于海平面上升的后果，松岛冰川和斯韦茨冰川在下个世纪将如何变化是一个极其重要的问题。我们将利用我们在大气环流方面的冰川退缩知识，对它们在下个世纪的变化作出改进的预测。我们将使用政府间气候变化专门委员会（ipcc）对西南极洲以北海域大气变化的预测。他们对不同温室气体增加的大气变化的预测将被使用，并将使我们能够确定环极深水的变化，从而确定下个世纪冰川的融化情况。

项目成果

Sources of uncertainty in projections of twenty-first century westerly wind changes over the Amundsen Sea, West Antarctica, in CMIP5 climate models

CMIP5 气候模型中南极洲西部阿蒙森海二十一世纪西风变化预测的不确定性来源

• DOI: 10.1007/s00382-013-2032-1
• 发表时间: 2014
• 期刊: Climate Dynamics
• 影响因子: 4.6
• 作者: Bracegirdle T

The Influence of the Amundsen-Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

• DOI: 10.1175/jcli-d-12-00813.1
• 发表时间: 2013-09-01
• 期刊: JOURNAL OF CLIMATE
• 影响因子: 4.9
• 作者: Hosking, J. Scott;Orr, Andrew;Phillips, Tony
• 通讯作者: Phillips, Tony

Retreat of Pine Island Glacier controlled by marine ice-sheet instability

• DOI: 10.1038/nclimate2094
• 发表时间: 2014-02-01
• 期刊: NATURE CLIMATE CHANGE
• 影响因子: 30.7
• 作者: Favier, L.;Durand, G.;Le Brocq, A. M.
• 通讯作者: Le Brocq, A. M.

Geometric and oceanographic controls on melting beneath Pine Island Glacier

• DOI: 10.1002/2013jc009513
• 发表时间: 2014-04-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
• 影响因子: 3.6
• 作者: De Rydt, J.;Holland, P. R.;Jenkins, A.
• 通讯作者: Jenkins, A.

The stability of grounding lines on retrograde slopes

• DOI: 10.5194/tc-6-1497-2012
• 发表时间: 2012-01-01
• 期刊: CRYOSPHERE
• 影响因子: 5.2
• 作者: Gudmundsson, G. H.;Krug, J.;Gagliardini, O.
• 通讯作者: Gagliardini, O.