Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure
As an inhomogeneous mixture of pure ice, brine, air and solid salts the physical properties of sea ice depend on its highly temperature-dependent microstructure. Understanding the microstructure and the way it responds to variations in temperature and salinity is crucial in developing an improved un...
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ftvictoriauwfig:oai:figshare.com:article/16985707 2023-05-15T13:41:47+02:00 Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure Jones, Keleigh Ann 2011-01-01T00:00:00Z https://doi.org/10.26686/wgtn.16985707 https://figshare.com/articles/thesis/Cross-Borehole_DC_Resistivity_Tomography_of_Sea_Ice_Temporal_and_Spatial_Variations_in_the_Anisotropic_Microstructure/16985707 unknown doi:10.26686/wgtn.16985707 https://figshare.com/articles/thesis/Cross-Borehole_DC_Resistivity_Tomography_of_Sea_Ice_Temporal_and_Spatial_Variations_in_the_Anisotropic_Microstructure/16985707 Author Retains Copyright Geophysics not elsewhere classified Electrical resistivity Microstructure Sea ice School: School of Chemical and Physical Sciences 040499 Geophysics not elsewhere classified Marsden: 260299 Geophysics Degree Discipline: Physics Degree Level: Doctoral Degree Name: Doctor of Philosophy Text Thesis 2011 ftvictoriauwfig https://doi.org/10.26686/wgtn.16985707 2023-03-16T00:13:42Z As an inhomogeneous mixture of pure ice, brine, air and solid salts the physical properties of sea ice depend on its highly temperature-dependent microstructure. Understanding the microstructure and the way it responds to variations in temperature and salinity is crucial in developing an improved understanding of the interaction between sea ice and the environment. However, measurements monitoring the microstructure of sea ice are difficult to obtain without disturbing its natural state. The brine fraction of sea ice is orders of magnitude more conductive than the solid ice, thus direct current resistivity techniques should yield information on sea ice microstructure. Due to the preferential vertical alignment of brine inclusions, the bulk resistivity of first-year sea ice is anisotropic, complicating interpretation of surface resistivity soundings. However, it can be shown that in a bounded anisotropic medium the resistivity structure may be resolved through in situ cross-borehole measurements. Measurement between borehole pairs, each containing one current and one potential electrode, allows the determination of the horizontal component of the anisotropic bulk resistivity (PH). Using three to four electrodes positioned at approximately the same depth in separate boreholes, provides an under-estimation of the geometric mean resistivity (Pm), and numerical modelling is required to retrieve an estimate of the true Pm. Combining these resistivities allows calculation of the vertical component of the bulk resistivity (PV). This thesis looks at results from measurements made in first year sea ice in April – June 2008 off Barrow, Alaska and in November 2009 off Ross Island, Antarctica. At Barrow, relatively quiescent conditions typically lead to a predominance of columnar ice, while more turbulent conditions and underwater ice formation in McMurdo Sound tend to produce a larger component of frazil or platelet ice. Interpretation of the resistivity measurements, aided by temperature and salinity data, shows that this ... Thesis Antarc* Antarctica Barrow McMurdo Sound Ross Island Sea ice Alaska Open Access Victoria University of Wellington / Te Herenga Waka Marsden ENVELOPE(66.067,66.067,-67.867,-67.867) McMurdo Sound Ross Island |
institution |
Open Polar |
collection |
Open Access Victoria University of Wellington / Te Herenga Waka |
op_collection_id |
ftvictoriauwfig |
language |
unknown |
topic |
Geophysics not elsewhere classified Electrical resistivity Microstructure Sea ice School: School of Chemical and Physical Sciences 040499 Geophysics not elsewhere classified Marsden: 260299 Geophysics Degree Discipline: Physics Degree Level: Doctoral Degree Name: Doctor of Philosophy |
spellingShingle |
Geophysics not elsewhere classified Electrical resistivity Microstructure Sea ice School: School of Chemical and Physical Sciences 040499 Geophysics not elsewhere classified Marsden: 260299 Geophysics Degree Discipline: Physics Degree Level: Doctoral Degree Name: Doctor of Philosophy Jones, Keleigh Ann Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
topic_facet |
Geophysics not elsewhere classified Electrical resistivity Microstructure Sea ice School: School of Chemical and Physical Sciences 040499 Geophysics not elsewhere classified Marsden: 260299 Geophysics Degree Discipline: Physics Degree Level: Doctoral Degree Name: Doctor of Philosophy |
description |
As an inhomogeneous mixture of pure ice, brine, air and solid salts the physical properties of sea ice depend on its highly temperature-dependent microstructure. Understanding the microstructure and the way it responds to variations in temperature and salinity is crucial in developing an improved understanding of the interaction between sea ice and the environment. However, measurements monitoring the microstructure of sea ice are difficult to obtain without disturbing its natural state. The brine fraction of sea ice is orders of magnitude more conductive than the solid ice, thus direct current resistivity techniques should yield information on sea ice microstructure. Due to the preferential vertical alignment of brine inclusions, the bulk resistivity of first-year sea ice is anisotropic, complicating interpretation of surface resistivity soundings. However, it can be shown that in a bounded anisotropic medium the resistivity structure may be resolved through in situ cross-borehole measurements. Measurement between borehole pairs, each containing one current and one potential electrode, allows the determination of the horizontal component of the anisotropic bulk resistivity (PH). Using three to four electrodes positioned at approximately the same depth in separate boreholes, provides an under-estimation of the geometric mean resistivity (Pm), and numerical modelling is required to retrieve an estimate of the true Pm. Combining these resistivities allows calculation of the vertical component of the bulk resistivity (PV). This thesis looks at results from measurements made in first year sea ice in April – June 2008 off Barrow, Alaska and in November 2009 off Ross Island, Antarctica. At Barrow, relatively quiescent conditions typically lead to a predominance of columnar ice, while more turbulent conditions and underwater ice formation in McMurdo Sound tend to produce a larger component of frazil or platelet ice. Interpretation of the resistivity measurements, aided by temperature and salinity data, shows that this ... |
format |
Thesis |
author |
Jones, Keleigh Ann |
author_facet |
Jones, Keleigh Ann |
author_sort |
Jones, Keleigh Ann |
title |
Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
title_short |
Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
title_full |
Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
title_fullStr |
Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
title_full_unstemmed |
Cross-Borehole DC Resistivity Tomography of Sea Ice: Temporal and Spatial Variations in the Anisotropic Microstructure |
title_sort |
cross-borehole dc resistivity tomography of sea ice: temporal and spatial variations in the anisotropic microstructure |
publishDate |
2011 |
url |
https://doi.org/10.26686/wgtn.16985707 https://figshare.com/articles/thesis/Cross-Borehole_DC_Resistivity_Tomography_of_Sea_Ice_Temporal_and_Spatial_Variations_in_the_Anisotropic_Microstructure/16985707 |
long_lat |
ENVELOPE(66.067,66.067,-67.867,-67.867) |
geographic |
Marsden McMurdo Sound Ross Island |
geographic_facet |
Marsden McMurdo Sound Ross Island |
genre |
Antarc* Antarctica Barrow McMurdo Sound Ross Island Sea ice Alaska |
genre_facet |
Antarc* Antarctica Barrow McMurdo Sound Ross Island Sea ice Alaska |
op_relation |
doi:10.26686/wgtn.16985707 https://figshare.com/articles/thesis/Cross-Borehole_DC_Resistivity_Tomography_of_Sea_Ice_Temporal_and_Spatial_Variations_in_the_Anisotropic_Microstructure/16985707 |
op_rights |
Author Retains Copyright |
op_doi |
https://doi.org/10.26686/wgtn.16985707 |
_version_ |
1766158048372457472 |