S.T. Lee Fellow Seminar: Frozen and liquid seawater problems
Friday, April 21, 2017 | noon-1:00pm, 401 IARC
Saline water makes up for roughly 97 % of all water found on planet Earth. Therefore, we naturally have to deal with this liquid on a regular basis. During this seminar, visiting S.T. Lee Fellow Eva Sutter will introduce two studies – both tied to saline waters and electrical current.
Sutter’s most recent work is directed toward understanding spectral induced polarization (SIP) signal responses from artificial sea ice in the low frequency range (1 kHz– 0.01 Hz). Previous laboratory and field studies suggest that low frequency SIP measurements, which reveal the frequency dependence of the bulk electrical conductivity/permittivity, may be able to give insight into sea ice microstructure. However, there is an absence of quality data for frequencies below 10 Hz, which this project attempts to contribute to. Sea ice microstructure-permittivity relationships will be further investigated for crude oil percolation experiments at a later stage of the four-week project. The results of this study may help in building early detection monitoring systems for under-sea ice oil pipeline leaks.
Another important aspect of seawater related problems will be covered in a second part of this seminar – saltwater intrusion into coastal aquifers. During two consecutive years repeat electrical resistivity tomography (ERT) measurements were able to determine seasonal and tidal cycles in seawater mixing behaviour within a shallow coastal sand aquifer. There are strong indications that progressing urbanization has a major influence on seasonal seawater intrusion patterns, and the dominant processes at the field locations were identified to be tied to freshwater pressure available over the course of a year. Within the smaller tidal cycle investigations, similarly behaving parts of the aquifer could be identified with different time series analysis techniques. These can be used to infer hydraulic properties of an aquifer and are thus of additional value for sustainable groundwater management in similar coastal environments.