Abstract
The seasonal evolution of sea-ice microstructure controls key ice properties, including those governing ocean–
atmosphere heat and gas exchange, remote-sensing signatures,
and the role of the ice cover as a habitat. Nondestructive
in situ monitoring of sea-ice microstructure is of value for sea-ice research and operations but remains elusive to date. We examine the potential for the electric properties of sea ice, which is highly sensitive to the brine distribution within the ice, to serve as a proxy for microstructure
and, hence, other ice transport properties. Throughout
spring of 2013 and 2014, we measured complex dielectric
permittivity in the range of 10 to 95 kHz in landfast ice off
the coast of Barrow (Utqia˙gvik), Alaska. Temperature and
salinity measurements and ice samples provide data to characterize ice microstructure in relation to these permittivity measurements. The results reveal a significant correlation between complex dielectric permittivity, brine volume fraction,and microstructural characteristics including pore volume and connectivity, derived from X-ray microtomography of core samples. The influence of temperature and salinity variations as well as the relationships between ice properties,microstructural characteristics, and dielectric behavior emerge from multivariate analysis of the combined data set.
Our findings suggest some promise for low-frequency permittivity measurements to track seasonal evolution of a combination of mean pore volume, fractional connectivity, and
pore surface area-to-volume ratio, which in turn may serve
as proxies for key sea-ice transport properties.
atmosphere heat and gas exchange, remote-sensing signatures,
and the role of the ice cover as a habitat. Nondestructive
in situ monitoring of sea-ice microstructure is of value for sea-ice research and operations but remains elusive to date. We examine the potential for the electric properties of sea ice, which is highly sensitive to the brine distribution within the ice, to serve as a proxy for microstructure
and, hence, other ice transport properties. Throughout
spring of 2013 and 2014, we measured complex dielectric
permittivity in the range of 10 to 95 kHz in landfast ice off
the coast of Barrow (Utqia˙gvik), Alaska. Temperature and
salinity measurements and ice samples provide data to characterize ice microstructure in relation to these permittivity measurements. The results reveal a significant correlation between complex dielectric permittivity, brine volume fraction,and microstructural characteristics including pore volume and connectivity, derived from X-ray microtomography of core samples. The influence of temperature and salinity variations as well as the relationships between ice properties,microstructural characteristics, and dielectric behavior emerge from multivariate analysis of the combined data set.
Our findings suggest some promise for low-frequency permittivity measurements to track seasonal evolution of a combination of mean pore volume, fractional connectivity, and
pore surface area-to-volume ratio, which in turn may serve
as proxies for key sea-ice transport properties.