TemperateReefBase Geonetwork Catalogue
Subantarctic zone oceanography - SAZ Project 1997-1998 - Oceanography Data
The circumpolar Subantarctic Zone (SAZ) is a globally significant region of water mass formation and carbon dioxide uptake from the atmosphere.
Here we synthesise the results of nine voyages over 8 years to describe the seasonal variation in mixed layer properties in the SAZ south of Australia for comparison with biogeochemical process studies carried out in late summer (March 1998) as part of the SAZ Project. Winter mixing extends to depths greater than 400 m, resulting in the formation of Subantarctic Mode Water. In summer the mixed layer shoals to 75-100 m, depths which are still sufficiently deep that phytoplankton growth may be light limited. Nitrate and phosphate concentrations are reduced in summer( e.g., nitrate decreases from greater than 15 to less than 5/ micro mol kg- 1) but remain well above limiting levels.
Silicate in contrast, is low throughout the year (4/micro mol kg- 1 in winter and less than 2 / micro mol kg- 1 in summer). Water mass properties along a north-south hydrographic section in March 1998 suggest that near-surface waters spread from south to north across the Subantarctic Front (SAF), supplying cool, fresh, nutrient-rich water to the SAZ. As a consequence, the properties of the southern SAZ differ from those farther north: the mixed layer in the south is cooler, fresher, deeper, higher in nutrients, and bounded below by a halocline (rather than by a seasonal thermocline, as in the northern SAZ). The contrast between the northern and southern SAZ persists throughout the year, suggesting the cross-front exchange occurs year-round and likely contributes to the differences in seasonal thermal amplitude and algal biomass accumulation seen in satellite images. Density-compensated horizontal gradients of temperature and salinity are common in the mixed layer of the SAZ and the northern SAF, consistent with the hypothesis that the vigour of lateral mixing in the mixed layer is a strong function of the magnitude of the lateral density gradient.
CTD Data are available for access via the provided URL. Data from the following voyages of the Aurora Australis were used:
1991-1992 Voyage 1
1992-1993 Voyage 9
1994-1995 Voyage 4
1994-1995 Voyage 7
1995-1996 Voyage 1
1996-1997 Voyage 1
1997-1998 Voyage 6
Simple
Identification info
- Alternate title
- Subantarctic zone oceanography - SAZ Project 1997-1998 - Oceanography Data
- Date (Publication)
- 2012-01-18
- Edition
- 1
Originator
Publisher
Principal investigator
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
- 1997-09-01 1998-03-31
Extent
- Description
- Vertical Extent - Depth
Vertical element
- Minimum value
- 800
- Maximum value
- 4000
- Identifier
- urn:x-ogc:def:cs:EPSG:6498
- Name
- Vertical CS. Axis: depth (D). Orientation: down. UoM: m.
- Identifier
- urn:x-ogc:def:axis:EPSG:113
- Name
- depth
- Title
- Seasonal evolution of the mixed layer in the Subantarctic Zone south of Australia
- Date (Publication)
- 2001
- Citation identifier
- 106
Author
- Name
- Journal of Geophysical Research
- Issue identification
- C12
- Page
- 31,447- 31,462
- NASA/GCMD Earth Science Keywords
-
- EARTH SCIENCE > OCEANS > OCEAN CIRCULATION > OCEAN MIXED LAYER
- EARTH SCIENCE > OCEANS > OCEAN CIRCULATION > WATER MASSES
- EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > OCEAN MIXED LAYER
- Keywords
-
- SAZ
- NASA/GCMD Earth Science Keywords
-
- SHIPS
- R/V AA > R/V Aurora Australis
- NASA/GCMD Earth Science Keywords
-
- AMD/AU
- CEOS
- AMD
- ACE/CRC
- NASA/GCMD Earth Science Keywords
-
- OCEAN > SOUTHERN OCEAN
- GEOGRAPHIC REGION > POLAR
Resource constraints
- Use limitation
- This metadata record is publicly available.
Resource constraints
- Access constraints
- licence
- Other constraints
- Copies of the referenced publications are available for download from the provided URL to AAD staff only. A large amount of data are available in the referenced publications. CTD data are publicly available for download via 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_2256_Oceanography when using these data.
- Language
- English
- Character encoding
- UTF8
Distribution Information
Distributor
Distributor
Distributor
- Fees
- free
- Units of distribution
- MB
- Transfer size
- 1.1
- Distribution format
-
- OnLine resource
-
GET DATA
Access CTD data used as part of this project. See Summary for details on which voyages to look at.
- OnLine resource
-
PROJECT HOME PAGE
Public information for ASAC project 2256
- OnLine resource
-
VIEW RELATED INFORMATION
Download point for the referenced publication
- OnLine resource
-
VIEW RELATED INFORMATION
Citation reference for this metadata record and dataset
Resource lineage
- Statement
- See the referenced papers for more information.
- Hierarchy level
- Dataset
- Maintenance and update frequency
- As needed
- Maintenance note
- 2012-01-18 - record created by Dave Connell. 2012-03-20 - record updated by Dave Connell to link to the CTD database. 2016-03-18 - record updated by Dave Connell - basic updates.
Metadata
- Metadata identifier
- string/ASAC_2256_Oceanography
- Language
- English
- Character encoding
- UTF8
Author
Sponsor
Owner
- Title
- Parent Metadata Record
- Citation identifier
- ASAC_2256
Type of resource
- Resource scope
- Dataset
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Citation identifier
- 5240e73e-9253-46b1-b5a5-9662b5bc783b
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Date (Last Revision)
- 2015-11-30T04:51:37
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_2256_Oceanography
Point of truth for the metadata record
- Date info (Creation)
- 2012-01-18T00:00:00
- 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
