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

O'Sadnick Megan E, Fairbanks AK

Investigators

Abstract

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.