EAPSI: Observing seasonal changes in sea ice microstructure with electric property measurements

海冰在极地地区发挥着许多作用，包括为海洋食物网底部的微生物提供栖息地；在极地社区的生活和文化中发挥不可或缺的作用；以及影响极地海洋的自然资源勘探。海冰的微结构不断演变，从秋季的形成到夏季的融化。然而，在观察这种季节性变化及其对海冰与周围环境相互作用的影响方面，存在着根本的挑战。为了获得有关冰性质的数据而取出冰芯的任何行为，都会导致卤水的立即损失和微结构的改变。野外地点的偏远也限制了观测。因此，人们正在探索连续、非破坏性地监测海冰微结构的方法。这个项目将研究海冰的电学特性，它对海冰中的卤水分布高度敏感，可以作为微结构的替代。这项研究将在惠灵顿维多利亚大学(VUW)与马尔科姆·英厄姆博士(Malcolm Ingham)合作进行，马尔科姆·英格姆博士是海冰电学特性的领军人物。该项目旨在将复介电常数这一特殊特性与海冰微结构的季节性演变联系起来。整个2013年春季，在阿拉斯加巴罗海岸进行了10赫兹至95千赫范围内的低频复介电常数测量。此外，还收集了温度和盐度测量以及冰样，以进一步描述冰的微结构。计划在2014年进行一组类似的测量，创建一个稳健的数据集，将低频复介电常数测量与关键海冰属性和微结构的季节性变化联系起来。在威斯康星大学对这一数据集进行分析，将能够建立一个改进的海冰微观结构模型，并导致进一步开发全年监测冰情的技术。该NSF EAPSI奖是与新西兰皇家学会合作资助的。

Sea ice plays many roles in Polar Regions including providing habitat for microorganisms at the base of marine food webs; playing an integral part in the lives and cultures of polar communities; and impacting natural resources exploration in the polar oceans. The microstructure of sea ice is constantly evolving from formation in the fall through melt in the summer. Fundamental challenges exist however, in observing this seasonal evolution and its effect on the interaction between sea ice and the surrounding environment. Any removal of ice cores to obtain data on ice properties, results in the immediate loss of brine and alterations of microstructure. The remoteness of field sites also limits observations. Methods to monitor sea ice microstructure continuously and non-destructively are therefore being explored. This project will study the potential for the electric properties of sea ice, highly sensitive to the brine distribution within to ice, to act as a proxy for microstructure. This research will be conducted at Victoria University of Wellington (VUW) in collaboration with Dr. Malcolm Ingham, a leading researcher on the electric properties of sea ice.This project aims to link one particular property, complex dielectric permittivity, to the seasonal evolution of sea ice microstructure. Throughout the Spring of 2013, measurements of low frequency complex dielectric permittivity in the range of 10Hz to 95kHz were made off the coast of Barrow, Alaska. Additionally, temperature and salinity measurements and ice samples were collected for further ice microstructure characterization. A similar set of measurements is planned for 2014 creating a robust dataset, the first of its kind, linking low frequency complex permittivity measurements to the seasonal evolution of key sea ice properties and microstructure. Analysis of this data set while at VUW will enable the creation of an improved microstructural model of sea ice and lead to further development of techniques to monitor ice conditions throughout the year. This NSF EAPSI award is funded in collaboration with the Royal Society of New Zealand.