Fluid permeability measurements taken on vertical component of sea ice during the SIPEX II voyage of the Aurora Australis, 2012
A 9 cm diameter Kovacs corer was used to drill holes partially through the ice. The core was removed, creating a pressure head in the hole. Packers made of ABS tubing wrapped with foam to create a tight seal were inserted into the holes to block the horizontal component of flow. A "Levelogger&q...
| Other Authors: | , , , , , , |
|---|---|
| Format: | Dataset |
| Language: | unknown |
| Published: |
Australian Antarctic Data Centre
|
| Subjects: | |
| Online Access: | https://researchdata.ands.org.au/fluid-permeability-measurements-australis-2012/701615 https://doi.org/10.26179/5d2811dcd3ad8 https://data.aad.gov.au/metadata/records/SIPEX_II_Fluid_Permeability http://nla.gov.au/nla.party-617536 |
| Summary: | A 9 cm diameter Kovacs corer was used to drill holes partially through the ice. The core was removed, creating a pressure head in the hole. Packers made of ABS tubing wrapped with foam to create a tight seal were inserted into the holes to block the horizontal component of flow. A "Levelogger", which is a pressure transducer for monitoring well-water, created by Solinst, was then inserted into each hole to record the change in water level over time. Each Levelogger was fitted into a plastic holder to keep it upright during measurement, which is a requirement for accurate data from the device. The temperature at the bottom of the core was measured immediately after removal, and the bottom 2 centimetres were removed for melting and subsequent measurement of salinity. The measurements of salinity and temperature enable calculation of the brine volume fraction. Solinst Levelogger software was then used to compensate for local barometric changes recorded using a Solinst Barologger. Following each measurement an auger was used to drill through the bottom of each hole to measure the ice thickness and freeboard in each hole. A full core was taken at each worksite for crystallographic study, immediately adjacent to where permeability measurements were taken. A temperature profile was taken on each of these cores immediately after extraction. Cores were then moved to a -20 degree C cold room for further processing. A thin vertical section, approximately 3mm thick, was taken from each of the cores stored for analysis. These sections were placed between a pair of cross polarised plates and photographed. Each photo was labelled with the core and date it was taken, and was photographed with a meter stick for scale. After the thin sections were photographed, the remaining samples were melted to measure salinity. Some of the melted sea ice was saved for later O18 analysis to distinguish samples containing snow-ice. Recorded values required to determine permeability are contained within the Master_Core_List.xls Excel spreadsheet, found in the Permeability worksheet. This worksheet is generated directly from notebook data, and contains the date, start and end time for each permeability record, the core number assigned, the depth of the partial sackhole, the levelogger serial number used, the station (site), the temperature 2cm from the bottom of the removed core, the bulk salinity from the bottom 2cm of the removed core, as well as the measured freeboard and thickness at each site. This worksheet also contains a column to indicate which crystal structure the crystallographic core taken from this site and depth had, as well as which crystallographic core this came from. Finally, the worksheet contains notes, and a column to indicate whether we believe this data is somehow bad. Please see the notes section for reasons why a data point was determined invalid. Typically was due to heavy rafting beneath the flow or too quick an influx of water to properly measure. All permeability data can be found both in the original binary .xle format used by Solinst levelogger software, as well as exported into comma separated value (CSV) files. These files are located in the datalogger_data directory. Binary files are contained in the raw folder, organised into sub folders by station number. The CSV files are located in the csv folder, again organised into sub folders by station number. Photos of the crystallography cores can be found in the crystallography folder, separated into subfolders labelled with the site and core number. Each photo also contains a tag indicating the core number, site taken, date, and what depth range this covers. Tags may not contain a depth range for cores less than 1 meter. Please see the meter stick in each photo for scale. Scans of the original notebooks from which the Permeability worksheet were created are provided in the scanned_notebook directory. |
|---|