Ocean2Ice: Processes and variability of ocean heat transport toward ice shelves in the Amundsen Sea Embayment

Ocean2Ice：阿蒙森海湾冰架海洋热传输的过程和变化

基本信息

批准号：
NE/J005746/1
负责人：
Adrian Jenkins
金额：
$ 30.24万
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：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ005746%2F1
关键词：
Ocean2Ice Processes variability ocean heat

项目摘要

Imagine that the ocean is like a large gin and tonic. When you add ice to the drink, the level in the glass goes up. When the lump of ice melts, the level in the glass doesn't change, because the ice is floating. When ice that is currently resting on land in Antarctica goes into the sea, either as an iceberg or as meltwater, the sea level all over the world goes up. It used to be thought that the same amount of water went back to the Antarctic as snowfall, to compensate for the icebergs and meltwater, so the whole system was in balance. But some glaciers in the Antarctic (and Greenland) seem to be melting at a faster rate than they are being replaced. So the total amount of ice is getting smaller, because more of that water is in the ocean, adding to sea level rise. This is worrying, because we don't really know why this is happening, and if we can't understand why, it's difficult to predict whether future sea level will carry on increasing at a faster and faster rate, or whether it will slow down or go back to equilibrium. Governments planning sea level defences in low-lying areas for the next decades need to have a more certain prediction of likely levels. That means that the big computer models that they use to forecast future climates need to have even better and more complex physics than they do already.So, what can scientists do to find out why the ice is melting? When the glaciers finally reach the sea, they float on the seawater, as an ice shelf. One suggestion is that the ocean is providing more heat to melt the ice than it used to do. Even though the ocean isn't that warm in the Antarctic, it is a few degrees above freezing, and if it washes underneath the ice shelves it can give up a lot of heat. What we plan to do in this project is to go to one of the fastest melting glaciers, the Pine Island Glacier in the Amundsen Sea, Antarctica. This is one of the most remote parts of our planet - imagine going to the Pacific Ocean and then heading south until you meet Antarctica. We will put some instruments in the water near the ice shelf, to see how and why the warm ocean water gets close to the ice. Is it the wind that forces the water there? Is it waves going round the Antarctic continent? Does the water get channelled up troughs in the sea floor gouged by glaciers thousands of years ago?We plan to use some novel equipment in the Antarctic, such as gluing tiny sensors onto elephant seals' fur. The seals will remain in the area over winter, long after we've gone back home. Their sensors will send back information about the seals' habitat - for example the temperature and the saltiness. This is useful for us because we can't get observations in the wintertime any other way because the area is covered in sea ice. And it's good for the seals because it will help our biologist colleagues to better understand how vulnerable the elephant seals might be to climate change. We'll also put in the water a mechanical version of a seal, called a Seaglider. This goes up and down in the water making measurements as it goes, and much like the seal sensors, it will communicate when it's at the surface using mobile phone. While we're there with the ship, we'll make lots of measurements of the temperature and saltiness of the water, how fast it's going, and how mixed up it is. Looking at all these data sets together should give us a better understanding of how the heat is getting to the glacier.One of the important tools will be a variety of computer models. These will range from all-singing, all-dancing climate models, that try to include ice, ocean and atmosphere all interacting, to much simpler models that test our understanding of the physics at play. The final result of the work we plan to do should be better climate models to predict future sea levels.

想象一下，海洋就像一大杯杜松子酒和补品。当您向饮料中添加冰块时，玻璃杯中的液位会上升。当冰块融化时，玻璃杯中的液位不会改变，因为冰是漂浮的。当目前南极洲陆地上的冰以冰山或融水的形式进入海洋时，世界各地的海平面都会上升。过去人们认为，与降雪等量的水返回南极，以补偿冰山和融水，因此整个系统处于平衡状态。但南极洲（和格陵兰岛）的一些冰川融化速度似乎比替换速度还要快。因此，冰的总量越来越少，因为更多的水存在于海洋中，从而加剧了海平面的上升。这是令人担忧的，因为我们并不真正知道为什么会发生这种情况，如果我们不能理解为什么，就很难预测未来海平面是否会继续以越来越快的速度上升，或者是否会放缓或回到平衡状态。规划未来几十年低洼地区海平面防御的政府需要对可能的水平进行更确定的预测。这意味着他们用来预测未来气候的大型计算机模型需要比现有的更好、更复杂的物理学。那么，科学家们可以做些什么来找出冰融化的原因呢？当冰川最终到达大海时，它们漂浮在海水上，就像冰架一样。一种建议是，海洋比以前提供了更多的热量来融化冰。尽管南极洲的海洋没有那么温暖，但温度却比冰架高几度，如果海水冲刷到冰架下面，就会释放出大量的热量。我们在这个项目中计划做的是前往融化最快的冰川之一——南极洲阿蒙森海的松岛冰川。这是地球上最偏远的地区之一 - 想象一下前往太平洋，然后向南行驶直到遇到南极洲。我们将在冰架附近的水中放置一些仪器，以了解温暖的海水如何以及为何接近冰。是风把水吹到那里的吗？是环绕南极大陆的波浪吗？水是否会被引导到数千年前被冰川挖出的海底槽中？我们计划在南极使用一些新颖的设备，例如将微型传感器粘在象海豹的毛皮上。在我们回家后很长一段时间里，海豹都会留在这个地区过冬。他们的传感器将发回有关海豹栖息地的信息，例如温度和咸度。这对我们很有用，因为我们无法以任何其他方式在冬季进行观测，因为该地区被海冰覆盖。这对海豹有好处，因为它将帮助我们的生物学家同事更好地了解象海豹对气候变化的脆弱性。我们还将在水中放入机械版密封件，称为“Seaglider”。它在水中上下移动，进行测量，就像密封传感器一样，它在水面时会使用手机进行通信。当我们在船上时，我们将对水的温度和盐度、水流的速度以及水的混合程度进行大量测量。将所有这些数据集放在一起应该可以让我们更好地了解热量是如何到达冰川的。重要的工具之一是各种计算机模型。这些模型的范围包括从会唱歌、会跳舞的气候模型（试图将冰、海洋和大气相互作用全部纳入其中）到更简单的模型（测试我们对物理原理的理解）。我们计划做的工作的最终结果应该是更好的气候模型来预测未来的海平面。