Atmosphere to ocean momentum transfer by sea ice

通过海冰将大气向海洋的动量传递

基本信息

批准号：
NE/M015025/1
负责人：
Daniel Feltham
金额：
$ 40.62万
依托单位：
University of Reading
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FM015025%2F1
关键词：
Atmosphere ocean momentum transfer sea

项目摘要

In response to global warming, the ice covers of the Arctic and Antarctic are changing, with a significant reduction in the summer extent of Arctic sea ice. The reduction of Arctic sea ice is more rapid and extreme than climate models predict, suggesting that these models do not adequately represent the processes controlling this reduction. The reduced summer Arctic sea ice cover, and changes to the winter sea ice cover, affect the mechanical and thermodynamic coupling between the air and ocean. In fact, observations show that the sea ice cover has become more mobile in the last 15 years and that there has been an increase in the mean ocean circulation beneath the sea ice. Since, over the same period, there has not been an observed increase in wind strength, this suggests that changes to the sea ice cover itself are responsible for an enhanced ice motion and transfer of wind stress to the ocean beneath sea ice. Our project hypothesis is: Changes in the Arctic sea ice cover have resulted in a more efficient transfer of momentum between the air and ocean, resulting in spin up of sea ice and the Arctic Ocean. We will test this hypothesis with a combination of new data, theory and numerical modelling. We will investigate how changes in the roughness of the ice cover, e.g. through a more dilute ice cover having more floe edges exposed, change the drag forces exerted by the air on the ice and the ice on the ocean. We will investigate how a reduction in the ice cover may reduce the resistance of the ice cover to the wind, allowing it to move more easily. In particular we address the question: to what extent is acceleration of the Arctic sea ice gyre the result of decreased ice forces versus increased drag? We will use climate models containing new physics calibrated with, and derived from, new observations, to examine the prediction that: Changes in the sea ice cover will continue to lead to enhanced momentum transfer between the air and ocean, resulting in a more mobile and responsive ice cover and enhanced flow and mixing in the Arctic Ocean. Although we focus our analysis on the Arctic Ocean, where sea ice changes have been more dramatic, we will also examine air-ice-ocean momentum exchanges in the Southern Ocean. This proposal brings together leading researchers in sea ice dynamics, remote sensing, ocean and climate modelling, and builds upon existing expertise in satellite observation, theory, and modelling of sea ice in the Centre for Polar Observation and Modelling. In addition to the scientific outcomes, the proposed work will result in new sea ice drag physics being incorporated into a sea ice climate model and delivered to climate modelling groups. This will directly help scientists investigating and predicting future changes to the sea ice cover in the Arctic and Southern Oceans and also help scientists trying to understand and predict changes in the global climate system.

为了响应全球变暖，北极和南极的冰盖正在发生变化，北极海冰的夏季程度大大减少。北极海冰的减少比气候模型预测的要快速，更极端，这表明这些模型不能充分代表控制这种降低的过程。减少的夏季北极海冰覆盖物以及冬季海冰盖的变化影响了空气和海洋之间的机械和热力学耦合。实际上，观察结果表明，在过去的15年中，海冰覆盖率变得更加流动，并且海冰下的平均海洋循环增加了。由于在同一时期尚未观察到风强度的提高，因此这表明海冰盖的变化本身是造成增强的冰运动和风应力向海冰下海洋的转移。我们的项目假设是：北极海冰覆盖的变化导致空气和海洋之间动量的更有效地转移，从而导致海冰和北极海洋旋转。我们将结合新数据，理论和数值建模来检验这一假设。我们将研究冰盖粗糙度的变化，例如通过更稀释的冰盖，露出了更多的花边缘，改变了空气在冰上施加的阻力和海洋上的冰。我们将调查冰盖的减少如何降低冰盖对风的阻力，从而使其更容易移动。特别是我们解决了一个问题：北极海冰盖尔的加速度在多大程度上是冰力减少与阻力增加的结果？我们将使用包含由新观测校准并得出的新物理学的气候模型，以研究以下预测：海冰覆盖的变化将继续导致空气和海洋之间的动量转移增强，从而导致更加移动反应性的冰盖和增强的流动和北极海洋混合。尽管我们将分析重点放在北极海洋上，但海冰的变化更加戏剧化，但我们还将检查南海洋中的冰冰球动量交流。该提案汇集了海冰动力学，遥感，海洋和气候建模的领先研究人员，并建立在卫星观测，理论和海冰建模中的现有专业知识的基础上。除了科学的结果外，拟议的工作还将导致新的海冰阻力物理学纳入海冰气候模型并交付给气候建模组。这将直接帮助科学家调查并预测北极和南大洋中海冰覆盖的未来变化，并帮助科学家试图理解和预测全球气候系统的变化。