Nella Dan: AAMBER Cruise - Oceanography data
Some problems were experienced with the conductivity cell freezing, and after March 3rd, 1987 only temperature profiles could be taken. Oceanography measurements were taken where possible, which was not always at ideal locations. Therefore coverage of the area is not necessarily complete. This cruis...
| Other Authors: | , |
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| Format: | Dataset |
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Australian Ocean Data Network
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| Online Access: | https://researchdata.ands.org.au/nella-dan-aamber-cruise-oceanography/686863 https://data.aad.gov.au/metadata/records/AAMBER_ocean http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=813 http://data.aad.gov.au/aadc/marine_science/underway_extraction/index.cfm http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAMBER_ocean |
| Summary: | Some problems were experienced with the conductivity cell freezing, and after March 3rd, 1987 only temperature profiles could be taken. Oceanography measurements were taken where possible, which was not always at ideal locations. Therefore coverage of the area is not necessarily complete. This cruise is however part of a series of 6 cruises which operated in this area, providing data from varying seasons and condition. Data collection: A Neil Brown Mark III CTD (conductivity, temperature, depth probe #1103) system attached to a rosette water sampler (General Oceanics) was used for collecting continuous vertical profiles of conductivity and temperature. Water samples were collected at different depths using the rosette water sampler with 5L Niskin bottles. Measurements were made on the downcast, and water samples collected on the upcast. The water sampling depths were determined depending on the readings made during the downcast. The CTD was lowered at a rate as close to 1 m/sec, and raised between samples at speeds between 1 and 2 m/sec. Conductivity and temperature readings were also made at each water sampling station. 94 CTD stations were taken. Ship-board processing: Water samples were analysed on board the ship for salinity and oxygen. Post-ship processing: Oceanography data - Data was initially recorded on audio cassettes, but later replayed to produce digital nine-track magnetic tapes by a PDP 11/23. Data tapes were then processed on a VAX 11/750. For each CTD downcast, an uncalibrated, de-spiked file was generated, using a recursive filter to compensate for sensor mismatch. The data files were used to generate 2 dbar averages for in situ temperature, salinity, sigma-t, specific volume anomaly and geopotential anomaly. The averages were centred on even, integral depths, and were only calculated when averages contained eight or more valid data points. The temperature and conductivity means were calculated for the interval, and the salinity calculated for the mid point of the pressure interval from the temperature and salinity means. Data processing software was supplied by CSIRO Division of Oceanography. The complete dataset is logically consistent, as krill and zooplankton hauls and phytoplankton pigment analysis were also obtained at the same sampling sites as the oceanographic and nutrient data. The cruise track was established before the experiment in order to eliminate bias. The oceanographic sampling was done as a supplement to the krill research program, so sampling location and depth were not necessarily selected according to oceanographic related considerations. This dataset contains CTD (conductivity, temperature, depth) data obtained from the Australian Antarctic Marine Biological Ecosystem Research (AAMBER) 86/87 cruise of the Nella Dan, during Feb - Apr 1987. This cruise is the last out of a series of six, conducting a long term field survey on krill, fish and zooplankton. 94 CTD casts were taken in the Prydz Bay region, as a supplement to the krill and fish research program. Casts were made to the bottom over the continental shelf, and to either 200 m or 1000 m off the shelf. This dataset is a subset of the whole cruise data. The fields in this dataset are: Pressure Temperature Sigma-T Salinity Geopotential Anomaly Specific volume Anomaly samples deviation conduction |
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