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，包括在海洋食物网的基础上为微生物提供栖息地;在极地社区的生活和文化中发挥不可或缺的作用;并影响极地海洋的自然资源勘探。海冰的微观结构从秋季的形成到夏季的融化不断演变。然而，在观察这种季节性演变及其对海冰与周围环境之间相互作用的影响方面存在着根本性的挑战。为获取冰的性质数据而对冰芯进行的任何移除都会导致盐水的立即损失和微观结构的改变。野外地点的偏远也限制了观测。因此，正在探索以非破坏性方式连续监测海冰微观结构的方法。该项目将研究海冰电特性的潜力，对冰内盐水分布高度敏感，可作为微观结构的代表。这项研究将在惠灵顿的维多利亚大学（VUW）与海冰电特性的主要研究人员Malcolm Ingham博士合作进行。该项目旨在将一种特殊的特性--复介电常数与海冰微观结构的季节性演变联系起来。整个2013年春季，在阿拉斯加州巴罗海岸外进行了10 Hz至95 kHz范围内的低频复介电常数的测量。此外，还收集了温度和盐度测量结果以及冰样品，以进一步表征冰的微观结构。计划在2014年进行一系列类似的测量，创建一个强大的数据集，这是第一个此类数据集，将低频复介电常数测量与关键海冰特性和微观结构的季节性演变联系起来。在VUW对这些数据集的分析将有助于建立一个改进的海冰微观结构模型，并进一步发展全年监测冰况的技术。这个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.