CHARACTERIZATION OF BRINE NETWORK MICROSTRUCTURE IN FIRST YEAR ARCTIC SEA ICE

北极海冰调节着海洋和大气之间的热量、流体和气体交换，并在全球气候中发挥着重要作用。海冰是高度不均匀的，结构、化学和相变化发生在非常短的时间和相对温度尺度上。目前北极海冰覆盖面积的迅速减少伴随着从多年冰到主要是一年海冰和较薄海冰的转变。目前对海冰中盐水网络形态及其变化的了解，对于最准确地解释海冰数据以及在区域和更大尺度气候模式中使用都是不够的。利用微x射线计算机断层扫描和应用数学，研究人员建议详细描述第一年海冰中盐水网络的形态和变化。拟议工作的总体目标是提高我们确定热量、气体、化学物质和盐通过海冰和在海冰内运输的能力，特别是阐明盐水排放和海水淡化过程以及它们如何随温度变化。利用冰的微观结构分析和应用数学方面的经验，研究人员将对第一年海冰的孔隙微观结构进行定量的物理描述，然后用这些描述来解释体积性质。他们将使用实验室种植的海冰和在阿拉斯加巴罗收集的第一年自然海冰。作为该项目的一部分，研究人员将设计和建造一个系统，用于储存和运输在原位温度梯度下测量的海冰核心，他们将与其他研究人员公开分享。这项工作的智力价值在于它发展了第一年海冰孔隙微观结构的定量物理描述，可用于解释整体物理性质，并将有助于科学界对海冰覆盖及其在对流层化学中的作用的理解。它还将有助于改进区域和全球气候模式，并有助于了解北极环境过程及其在气候变化中的作用。拟议活动的更广泛影响包括培养一名博士后科学家，并将研究和工程与一些本科生的教育直接结合起来，这些本科生将设计仪器，参与实验室和实地工作，共同撰写论文，并参加会议。研究结果将发表在国际评审期刊上，在会议上展示，在巴罗的北极社区和其他听众的公开演讲中展示，并放在网页上。这些数据也将通过国家冰雪数据中心提供。

Arctic sea ice mediates the exchange of heat, fluids, and gases between the ocean and the atmosphere, and in doing so plays an important role in global climate. Sea ice is highly heterogeneous, with structural, chemical and phase changes occurring on very small time and relative temperature scales. The current rapid decline of the Arctic sea ice cover is accompanied by a transition from multi-year ice to mostly first-year and thinner sea ice. Current understanding of the morphology of brine networks in sea ice, and their variability, is inadequate both for the most accurate interpretation of sea ice data and for use in regional and larger scale climate models. Using micro X-ray computed tomography and applied mathematics, the investigators propose to describe in detail the morphology and variability of brine networks in first-year sea ice. The overall goal of the proposed work is to improve our ability to determine the transport of heat, gases, chemical species, and salts through and within sea ice, and specifically to shed light on the brine drainage and desalination processes and how they change with temperature. Drawing on experience in both microstructural analysis of ice and applied mathematics, the investigators will produce quantitative physical descriptions of pore microstructure in first year sea ice, which can then be used to interpret bulk properties. They will use both laboratory grown sea ice and natural first year sea ice collected at Barrow, Alaska. As part of this project, the investigators will design and build a system for storing and transporting sea ice cores at their measured in situ temperature gradients, which they will share openly with other researchers. The intellectual merit of the proposed work lies in its development of quantitative physical descriptions of pore microstructure in first year sea ice, which can be used in interpretation of bulk physical properties, and which will contribute to the scientific community's understanding of sea ice cover and its role in tropospheric chemistry. It will also contribute to the improvement of regional and global climate models, and to the understanding of Arctic environmental processes and their role in climate change. The broader impacts of the proposed activity include the training of a postdoctoral scientist and direct integration of research and engineering with education for a number of undergraduate students who will design apparatus, take part in laboratory and field work, co-author papers, and participate in conferences. The results of the research will be published in international refereed journals, presented at conferences, presented in public lectures to the Arctic community in Barrow and to other audiences, and placed on a web page. The data will also be available through the National Snow and Ice Data Center.