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Sniffer (Hydrocarbon Detection) Data Hydrocarbon Migration and Seepage in the Timor Sea and Browse Basin. An Integrated SAR and Geological Study GIS.Note: This metadata describes the dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines Version 2. Dataset citationANZLIC unique identifier: ANZCW0703003367 Title: Sniffer (Hydrocarbon Detection) Data Hydrocarbon Migration and Seepage in the Timor Sea and Browse Basin. An Integrated SAR and Geological Study GIS. CustodianCustodian: Geoscience Australia Jurisdiction: Australia DescriptionAbstract: Sniffer Files The 'Sniffer' or Direct Hydrocarbon Detection (DHD) technique used to detect hydrocarbon seepage offshore involves towing a submerged tow-fish close to the seafloor and continuously pumping seawater into a geochemical laboratory on board where the hydrocarbons are extracted and measured by gas chromatography. The Direct Hydrocarbon Detection (DHD) method continuously analyses C1-C8 hydrocarbons within seawater. The method used on the RV Rig Seismic is as follows. Seawater is continuously delivered into the geochemical laboratory onboard the ship via a submersible fish (which is towed approximately 10 m above the seafloor). The seawater is degassed in a vacuum chamber and the resulting headspace gas is injected into three gas chromatographs, which sequentially sample the flowing gas stream and measure a variety of light hydrocarbons. Total hydrocarbons (THC) are measured every thirty seconds, light hydrocarbons (C1-C4) are measured every two minutes and C5 to C8 are measured every 8 minutes. Fluorometer and Aquatrack Fil In October 1998, the Australian Geological Survey Organisation (AGSO) carried out field trials of three commercially available towed fluorometers; Aquatracka (Chelsea Instruments), SAFIRE (WetLabs), FLF (WetLabs). These instruments were pre-selected on manufacturer specifications as potentially the most suitable, compared to other fluorometers currently on the market, for the detection of polycyclic aromatic hydrocarbons (PAH) present in crude oils seeping into the marine environment. The fluorometers were set with an excitation wavelength in the range 239 nm to 260 nm and fluorescence was monitored over the range 340 nm to 360 nm. SAFIRE is a multi-wavelength instrument, which enabled simultaneous use of several excitation and emission wavelengths. All three fluorometers were mounted on deck and seawater was pumped through them. The Aquatracka instrument analysed deep water pumped to the surface by the "Sniffer" submersible system. ANZLIC search words:
Spatial domain:
Geographic extent name: AUSTRALIA INCLUDING EXTERNAL TERRITORIES - AUSAAT - Australia - Australia Geographic extent polygon: 121 -8.7, 127.5 -8.7, 127.5 -17, 121 -17, 121 -8.7, Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register
Data currencyBeginning date: 2000-07-01 Ending date: 2000-11-05 Dataset statusProgress: Complete Maintenance and update frequency: Not Known Access
Access constraints: Licence required Free Data DownloadData qualityLineage: Sniffer Data - Both Point and Line data A detailed description of the history of this data set can be found in "North West Shelf, Australia, Sniffer and Fluorometer Direct Hydrocarbon Detection Data", by MP Morse, AGSOCAT 34452 (unpublished). In summary the data from each survey was mapped to a consitent format and given a unique line number. A common subset of the parameters used by AGSO for seepage studies was extracted from each survey. These where then combined into one Microsoft Excel spreadsheet. The original survey data can be found on the data CD that is part of the AGSOCAT 34452. Aquatrack - Point data The acquisition of these data was synchronised with the "sniffer" operation and recorded as part of that system. These data were archived seperately from the "sniffer" data and also mereged with the other fluorometer data as Microsoft Excel spreadsheets. Fluorometer - Point Data The FLF and SAFIRE data sets were acquired using there own proprietary acquisition systems as time based data. Positions for these data were interpolated from the navigation data recorded with the Aquatracka and "sniffer" data on the same survey. This was done by matching the time data for each data set. The Aquatracka, FLF, and Safire data were then interleaved in time to create this dataset. Positional accuracy: No analysis of the positional accuracy of any of the vector features has been undertaken, however due to the accuracy of the data it can be considered that all vector features are within 50 metres of their true position. Sniffer Data The postions for these data were derived from the ship's navigation system. Surveys 94-99 used a stand alone GPS/Transit satellite fix/dead reconing system. Surveys 100-207 used a differential GPS system. Fluorometer/Aquatrack Data The postions for these data were derived from the ship's navigation system. Survey 207 used a differential GPS system. Attribute accuracy: All attributes for all files are explained in the following file included on the CDROM. All records, lookup tables and field explainations are found in this file: /timor_gis/sniffer/point_data/sniffer_tables.xls Logical Consistency: All vector data has been visually checked for extraneous points and value added data. Completeness: All vector data and details are complete and verified. Contact information
Metadata informationMetadata date: 2013-03-08 Additional metadataMetadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703003367.html Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703003367.xml All this data both vector and raster are part of the: Hydrocarbon Migration and Seepage in the Timor Sea and North Browse Basin, Northwest Shelf, Australia: An Intergrated SAR and Geological Study. A detailed description this data set can be found in "North West Shelf, Australia, Sniffer and Fluorometer Direct Hydrocarbon Detection Data", by MP Morse, AGSOCAT 34452. All data comes in vector format. COORDINATE SYSTEM DESCRIPTION Projection GEOGRAPHIC Datum WGS84 Units DD Authors:Morse, M. Webster, M. O'Brien, G. |
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