TemperateReefBase Geonetwork Catalogue
Brine flow through sea ice
Metadata record for data from ASAC Project 1060
See the link below for public details on this project.
Taken from the referenced publications:
Sea ice exhibits a marked transition in its fluid transport properties at a critical brine volume fraction Pc of about 5 percent, or temperature Tc of about -5 degrees Celsius for salinity of 5 parts per thousand. For temperatures warmer than Tc brine carrying heat and nutrients can move through the ice, whereas for colder temperatures the ice is impermeable. This transition plays a key role in the geophysics, biology, and remote sensing of sea ice. Percolation theory can be used to understand this critical behaviour or transport in sea ice. The similarity of sea ice microstructure to compressed powders is used to theoretically predict Pc of about 5 percent.
The snow cover on Antarctic sea ice often depresses the ice below sea level, allowing brine or seawater to infiltrate, or flood the snowpack. This significantly reduces the thermal insulation properties of the snow cover, and increases the ocean/atmosphere heat flux. The subsequent refreezing of this saturated snow or slush layer, to form snow-ice, can account for a significant percentage of the total ice mass in some regions. The extent of saturated snow cannot presently be estimated from satellite remote-sensing data and, because it is often hidden by a layer of dry snow, cannot be estimated from visual observations. Here, we use non-parametric statistics to combine sea-ice and snow thickness data from drillhole measurements with routine visual observations of snow and ice characteristics to estimate the extent of brine-infiltrated snow.
During a field experiment in July 1994, while the R.V. Nathaniel B. Palmer was moored to a drifting ice floe in the Weddell Sea, Antarctica, data were collected on the sea-ice and snow characteristics. We report on the evolution of ice which grew in a newly opened lead. As expected with the cold atmospheric conditions, congelation ice initially formed in the lead. Subsequent snow accumulation and large ocean heat fluxes resulted in melt at the base of the ice, and enhanced flooding of the snow on ice surface. This flooded snow subsequently froze, and, five days after the lead opened, all the congelation ice had melted and twenty-six centimetres of snow ice had formed. We use measured sea-ice and snow salinities, thickness and oxygen isotope values of the newly formed lead ice to calculate the salt flux to the ocean. Although there was a salt flux to the ocean as the ice initially grew, we calculate a small net fresh-water input to the upper ocean by the end of the 5 day period. Similar processes of basal melt and surface snow-ice formation also occurred on the surrounding, thicker sea ice. Oceanographic studies in this region of the Weddell Sea have shown that salt rejection by sea-ice formation may enhance the ocean vertical thermohaline circulation and release heat from the deeper ocean to melt the ice cover. This type of deep convection is thought to initiate the Weddell polynya, which was observed only during the 1970s. Our results, which show than an ice cover can form with no salt input to the ocean, provide a mechanism which may help explain the more recent absence of the Weddell polynya.
Simple
Identification info
- Alternate title
- Brine flow through sea ice
- Date (Publication)
- 2000-08-09
- Edition
- 1
Originator
Publisher
Principal investigator
Collaborator
- Name
- CAASM Metadata
- Other citation details
- Restricted access
- Status
- Completed
Custodian
- Topic category
-
- Oceans
Extent
))
Extent
- Description
- Temporal Coverage
Temporal extent
- TimePeriod
- 1994-07-01 1994-08-31
- Title
- Brine infiltration in the snow cover of sea ice in the eastern Weddell Sea, Antarctica.
- Date (Publication)
- 1998
- Citation identifier
- 27
Author
- Name
- Annals of Glaciology
- Page
- 461 - 465
- Title
- Snow-ice growth: a fresh water flux inhibiting deep convection in the Weddell Sea, Antarctica.
- Date (Publication)
- 2001
- Citation identifier
- 22
Author
- Name
- Annals of Glaciology
- Page
- 45 - 50
- Title
- The Percolation Phase Transition in Sea Ice.
- Date (Publication)
- 1998
- Citation identifier
- 282
Author
- Name
- Science
- Page
- 2238 - 2241
- NASA/GCMD Earth Science Keywords
-
- EARTH SCIENCE > CRYOSPHERE > SEA ICE > PACK ICE
- EARTH SCIENCE > CRYOSPHERE > SEA ICE > POLYNYAS
- EARTH SCIENCE > OCEANS > SALINITY/DENSITY > SALINITY
- EARTH SCIENCE > OCEANS > SALINITY/DENSITY
- EARTH SCIENCE > OCEANS > SEA ICE > HEAT FLUX
- EARTH SCIENCE > OCEANS > SEA ICE > ICE DEPTH/THICKNESS
- EARTH SCIENCE > OCEANS > SEA ICE > ICE TEMPERATURE
- EARTH SCIENCE > OCEANS > SEA ICE > POLYNYAS
- EARTH SCIENCE > OCEANS > SEA ICE > SNOW MELT
- EARTH SCIENCE > OCEANS > SEA ICE > SNOW DEPTH
- Keywords
-
- sea-ice
- Nathaniel B. Palmer
- snow cover
- brine
- infiltrate
- drillhole
- snowpack
- insulation
- NASA/GCMD Earth Science Keywords
-
- SHIPS
- R/V NBP > R/V Nathaniel B. Palmer
- NASA/GCMD Earth Science Keywords
-
- AMD/AU
- CEOS
- AMD
- ACE/CRC
- NASA/GCMD Earth Science Keywords
-
- OCEAN > SOUTHERN OCEAN
- CONTINENT > ANTARCTICA
- GEOGRAPHIC REGION > POLAR
- OCEAN > SOUTHERN OCEAN > WEDDELL SEA
Resource constraints
- Use limitation
- This metadata record is publicly available.
Resource constraints
- Access constraints
- licence
- Other constraints
- PDF copies of the referenced papers are available for download by AAD staff at the provided URL.
Resource constraints
- File type
- Portable Network Graphic
- Title
- Attribution 4.0 International (CC BY 4.0)
- Website
-
https://creativecommons.org/licenses/by/4.0/legalcode
Legal code for Creative Commons by Attribution 4.0 International license
- Use constraints
- licence
- Other constraints
- This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_1060 when using these data.
- Language
- English
- Character encoding
- UTF8
Distribution Information
Distributor
Distributor
Distributor
- Fees
- Free
- Units of distribution
- MB
- Transfer size
- 7.90
- Distribution format
-
- OnLine resource
-
PROJECT HOME PAGE
Public information for ASAC project 1060
- OnLine resource
-
VIEW RELATED INFORMATION > PUBLICATIONS
Download point for the papers - AAD Only
- OnLine resource
-
VIEW RELATED INFORMATION
Citation reference for this metadata record and dataset
Resource lineage
- Statement
- Values provided in temporal and spatial coverage are approximate only.
- Hierarchy level
- Dataset
- Maintenance and update frequency
- As needed
- Maintenance note
- 2010-09-02 - record updated by Rhiannon Powell and Olivia Mitchell. 2010-10-11 - record updated by Dave Connell to link the scanned papers. 2014-12-09 - record updated by Dave Connell - basic updates.
Metadata
- Metadata identifier
- string/ASAC_1060
- Language
- English
- Character encoding
- UTF8
Author
Sponsor
Owner
Type of resource
- Resource scope
- Dataset
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Citation identifier
- 43cef222-466f-4793-8cbd-f87db8a62820
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Date (Last Revision)
- 2015-11-30T04:05:17
Identifier
- Description
- metadata.extraction_date
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Citation identifier
- 8.6
- Metadata linkage
-
http://data.aad.gov.au/metadata/records/ASAC_1060
Point of truth for the metadata record
- Date info (Creation)
- 2000-08-09T00:00:00
- Date info (Last Update)
- 2017-04-26
Metadata standard
- Title
- ISO 19115-3
- Edition
- 2014
- Other citation details
- Version 1
- Title
- DIF to ISO 19115-1 Profile
Overviews
Spatial extent
Provided by
