Synoptic Antarctic Shelf-Slope Interactions Study: SASSI UK

南极陆架-斜坡相互作用天气研究：SASSI UK

• 批准号: NE/E012965/1
• 负责人: Karen J. Heywood
• 金额: $ 45.63万
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FE012965%2F1
• 关键词: Synoptic; Antarctic; Shelf; Slope; Interactions

The oceans contain salt that makes the water denser. Fresh water does not contain salt, and usually lies on top of the denser salty water.We now know that the amount of fresh water on the margins of Antarctica affects global climate, at least in the latest climate models. These climate models are still very crude, because we have to simplify them to make them run on our fastest computers in a reasonable time. Nevertheless we think that the large-scale behaviour of the models is probably similar to that in the real world. When we add additional fresh water around Antarctica in the model, the climate of Europe changes over a time scale as short as 5 years. This means that even places we think of as remote are in fact just as important to study as those close to us. We also believe that Antarctica is an important place to study because it is one of the places where the dense cold water sinks to the sea bed and flows towards the equator in what oceanographers call the thermohaline circulation. If this thermohaline circulation slows down then global climate is affected, as was dramatised in the film 'The Day After Tomorrow'. Because Antarctica is remote, and difficult and expensive to get to, we have very little information about the oceanographic characteristics, such as temperature or current velocity, and the amount of salt in the water, which we term salinity. It is especially difficult to obtain measurements close to Antarctica in winter, because most of the ocean is covered in a thick layer of frozen sea water, called sea ice. Observations suggest that changes in global climate are affecting the amounts of fresh water on the continental shelf of Antarctica. It seems that the ice sheets (on the Antarctic continent) and ice shelves (the floating parts of the ice sheet, where it meets the sea) may be melting more quickly than before, at least in some locations. Under normal climate conditions, water evaporates from the ocean, falls as snow onto Antarctica and is compacted into ice. This ice then flows slowly towards the sea, where it calves into icebergs, which then melt back into the ocean. This circle of water through the ocean, atmosphere and ice is called the hydrological cycle. What may be happening now as climate changes is that some parts of this cycle are going faster than they used to, knocking the cycle out of its normal equilibrium. This project will study what is happening to the fresh water on the Antarctic continental shelf and slope. We will deploy for one year some moored instruments on the shelf and slope, measuring ocean temperature, salinity, current speed and direction, and sea level. Two of these instruments are very novel - one of them collects a sample of water every week and stores it in a bag ready for collection when we return a year later. The other will sit on the sea bed, and every day sends a little pod up to the surface on a length of wire and down again, measuring temperature and salinity as it goes. Because it sits in the deep water, it shouldn't get mown down by icebergs as they go by! These instruments are going to sit just upstream of the largest Antarctic Ice Shelf. We're going to test the idea that the ocean water upstream influences the amount of very cold, dense water that descends to the deep ocean there. Although studying the conditions around Antarctica is an ambitious thing to do, we are not doing it alone. Countries around the world are coming together for the International Polar Year in 2007-2009. We have agreed to all make measurements of the current velocity at the same time in different places around Antarctica. This will be the first time that this has been done and ought to tell us much more about what is happening to the oceans, ice and atmosphere around Antarctica, and why. This in turn should help us to make better climate models to predict the future of our planet.

海洋中含有盐，使水的密度更大。淡水不含盐，通常位于密度更大的盐水之上。我们现在知道，至少在最新的气候模型中，南极洲边缘的淡水数量会影响全球气候。这些气候模型仍然非常粗糙，因为我们必须简化它们，使它们在合理的时间内在我们最快的计算机上运行。然而，我们认为模型的大规模行为可能与现实世界中的行为相似。当我们在模型中加入南极洲周围额外的淡水时，欧洲的气候在短至5年的时间尺度上发生变化。这意味着，即使是我们认为遥远的地方，实际上也和我们附近的地方一样重要。我们还认为南极洲是一个重要的研究地点，因为它是稠密的冷水下沉到海床并流向赤道的地方之一，海洋学家称之为温盐环流。如果这种温盐环流减缓，那么全球气候就会受到影响，就像电影《后天》（the Day After Tomorrow）所描述的那样。因为南极洲地处偏远，到达那里既困难又昂贵，我们对海洋学特征的了解很少，比如温度或洋流速度，以及水中的盐含量，我们称之为盐度。冬天在南极洲附近进行测量尤其困难，因为大部分海洋都被一层厚厚的冻结海水所覆盖，这种海水被称为海冰。观测表明，全球气候的变化正在影响南极洲大陆架上的淡水量。看来冰盖（在南极大陆上）和冰架（冰盖的漂浮部分，与海洋交汇的地方）可能比以前融化得更快，至少在某些地方是这样。在正常的气候条件下，水从海洋中蒸发，以雪的形式落在南极洲，并被压缩成冰。然后这些冰慢慢流向大海，在那里形成冰山，然后冰山又融化回海洋。这种通过海洋、大气和冰的水循环被称为水循环。随着气候变化，现在可能发生的事情是，这个循环的某些部分比以前走得更快，使这个循环失去了正常的平衡。这个项目将研究南极大陆架和斜坡上的淡水正在发生什么变化。我们将在大陆架和斜坡上部署一些系泊仪器，测量海洋温度、盐度、洋流速度和方向以及海平面，为期一年。其中两种仪器非常新颖——其中一种每周收集一次水样，并将其储存在一个袋子里，准备一年后我们回来时收集。另一个则坐在海床上，每天用一根电线把一个小吊舱送到海面上，然后再下来，一边走一边测量温度和盐度。因为它位于深水中，所以它不应该被经过的冰山撞倒！这些仪器将位于最大的南极冰架的上游。我们要测试一下上游的海水是否会影响下到深海的低温高密度水的数量。虽然研究南极洲周围的环境是一件雄心勃勃的事情，但我们并不是独自在做这件事。世界各国齐聚一堂，迎接2007-2009年的国际极地年。我们已经同意在南极洲周围不同的地方同时测量当前的速度。这将是第一次这样做，应该会告诉我们更多关于南极洲周围的海洋、冰和大气发生了什么以及为什么发生了什么。这反过来又能帮助我们建立更好的气候模型来预测地球的未来。

项目成果

On the outflow of dense water from the Weddell and Ross Seas in OCCAM model

OCCAM模型中威德尔海和罗斯海浓水的流出

• DOI: 10.5194/os-8-369-2012
• 发表时间: 2012
• 期刊: Ocean Science
• 影响因子: 3.2
• 作者: Kerr R

Seasonal variability of water masses and transport on the Antarctic continental shelf and slope in the southeastern Weddell Sea

• DOI: 10.1002/jgrc.20174
• 发表时间: 2013-04-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
• 影响因子: 3.6
• 作者: Graham, Jennifer A.;Heywood, Karen J.;Holland, Paul R.
• 通讯作者: Holland, Paul R.

Coherent Seasonal Acceleration of the Weddell Sea Boundary Current System Driven by Upstream Winds

上游风驱动的威德尔海边界流系统的相干季节加速度

• DOI: 10.1029/2020jc016316
• 发表时间: 2020
• 期刊: Journal of Geophysical Research: Oceans
• 作者: Le Paih;Hattermann;Boebel;Kanzow;Lüpkes;Rohardt
• 通讯作者: Rohardt

An Overview of the Synoptic Antarctic Shelf-Slope Interactions (SASSI) project for the International Polar Year

• DOI: 10.5194/os-8-1117-2012
• 发表时间: 2012-01-01
• 期刊: OCEAN SCIENCE
• 影响因子: 3.2
• 作者: Heywood, K. J.;Muench, R.;Williams, G.
• 通讯作者: Williams, G.