Sea ice physical properties and their application to ocean-atmosphere interaction

海冰物理特性及其在海洋-大气相互作用中的应用

• 批准号: RGPIN-2015-03842
• 负责人: Galley, Ryan
• 金额: $ 1.46万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612606
• 关键词: Sea; ice; physical; properties; their

The long-standing concept that ocean-atmosphere interaction cannot occur through sea ice is invalid. We now understand sea ice provides a variably effective conduit for ocean-atmosphere exchange, particularly for CO2. It is now thought that sea ice (depending on its temperature) may produce CO2 as it forms or grows, which may be trapped within the ice and eventually exported to the deep ocean. These interactions are modulated by the shape, location and connectivity of its liquid and gas inclusions, the intrinsic properties of which are controlled by a vertical temperature gradient within the ice and depend also on the sea ice type and age. We aim to characterize the size, shape, location and connectedness of liquid and gas inclusions in sea ice and changes therein from formation to melting. These results are imperative in determining how much atmospheric CO2 may be sequestered in polar oceans over an annual cycle both through, and as a result of, sea ice processes. A significant obstacle to this work is the traditional methodology for sea ice sampling. That is, the vertical removal of a sea ice core from a larger volume and its subsequent storage at -20°C. Once a sea ice core sample is pulled upward and out of sea ice floating in the ocean, it’s no longer connecting the ocean and atmosphere, and the vertical temperature gradient that controls much of the physics we’re interested in is irreparably affected. This is especially relevant to the bottom portion of the sea ice bathed in ocean water through liquid channels extending upward into it. A useful analogy is a sponge removed from a sink of water. Removing the sponge from the sink and slicing it up it to see how much water it contained may not yield realistic results. The overarching goal of this program is methodological development. The limitations of sea ice coring and sample storage have been known for a long time; my students and I will endeavour to employ existing imaging techniques long used in other areas, and develop new state-of-the-art methods for the non-invasive measurement of the shape, location and type of sea ice inclusions. We would like to quantify how much liquid and air are in the proverbial sponge when it is floating in the sink, while it is floating in the sink. This work will greatly expand current knowledge on how sea ice affects the biogeochemical processes and CO2 fluxes between the ocean and atmosphere in polar seas. Results of this work will include a long-sought observationally-derived library of permeability data for sea ice, partitioned relatively by phase, (including liquid brine, gases and solid salts) for a variety of sea ice stages of development as a function of naturally wide ranging physical conditions. These results are vitally important for verification of existing theoretical approximations and modeling of sea ice brine retention, brine drainage and greenhouse gas transport through sea ice to the ocean below.

长期以来认为海洋与大气之间的相互作用不会通过海冰发生的概念是无效的。我们现在知道海冰为海洋-大气交换，特别是二氧化碳交换提供了一个有效的渠道。现在人们认为，海冰（取决于其温度）在形成或生长时可能会产生二氧化碳，这些二氧化碳可能被困在冰中，最终被排放到深海。这些相互作用是由其液体和气体包裹体的形状，位置和连通性调制，其内在属性是由冰内的垂直温度梯度控制，也取决于海冰的类型和年龄。我们的目标是表征海冰中液体和气体包裹体的大小，形状，位置和连通性以及从形成到融化的变化。这些结果是必不可少的，在确定有多少大气中的二氧化碳可能被封存在极地海洋在一个年度周期都通过，并作为一个结果，海冰过程。 这项工作的一个重大障碍是海冰取样的传统方法。也就是说，从更大的体积中垂直取出海冰核心，然后将其储存在-20 ° C。一旦海冰核心样本被向上拉，从漂浮在海洋中的海冰中取出，它就不再连接海洋和大气，控制我们感兴趣的大部分物理学的垂直温度梯度就受到了不可挽回的影响。这一点与通过向上延伸的液体通道浸泡在海水中的海冰底部特别相关。一个有用的类比是从水槽中取出的海绵。从水槽中取出海绵并将其切片，看看它含有多少水可能不会产生现实的结果。 该计划的首要目标是方法的发展。海冰取芯和样品储存的局限性早已为人所知;我和我的学生将努力采用其他领域长期使用的现有成像技术，并开发新的最先进的方法，用于非侵入性测量海冰内含物的形状、位置和类型。我们想量化有多少液体和空气在谚语中的海绵时，它是浮动在水槽，而它是浮动在水槽。 这项工作将极大地扩展目前关于海冰如何影响极地海洋的海洋地球化学过程和海洋与大气之间的CO2通量的知识。这项工作的结果将包括一个长期寻求的观测得出的海冰渗透率数据库，相对分区相，（包括液体盐水，气体和固体盐）的各种海冰发展阶段的功能，自然广泛的物理条件。这些结果是非常重要的验证现有的理论近似和模拟海冰盐水滞留，盐水排水和温室气体通过海冰下的海洋运输。