Brief description
This record describes the Conductivity-Temperature-Depth (CTD) data collected from the Marine National Facility RV Investigator voyage IN2017_V01 titled: "Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles." The voyage took place from Hobart (TAS) to Hobart between the 14th January and 5th March, 2017.Data for 33 deployments were acquired during this voyage using a Seabird SBE911 CTD, fitted with 36 twelve litre bottles on the rosette sampler. Casts 1-10, 13 – 33 were acquired using the Seabird SBE911 CTD unit 20, and casts 11 and 12 were acquired using the Seabird SBE911 CTD unit 22. CTD and sensors were changed in efforts to remediate sensor issues. CSIRO -supplied calibration factors were used to compute the pressures, and preliminary temperature and conductivity values. The data were subjected to automated QC to remove spikes and out-of-range values.
Processing was completed using CapPro processing software, version 2.9.
For the duration of the voyage significant spikes were observed across all recorded sensor channels. Investigation strongly suggests electrical interference was the cause of the data spikes, as mitigation measures have alleviated the issue. Care was taken in post processing to remove the spikes while maintaining true data features. The nature of the spiking was primarily extreme values persisting for a single scan, which were suitably detected and flagged by evaluating the second-difference of the data. An additional filter was also applied to the data which evaluated the median and standard deviation of the conductivity over a moving window, which was used to detect extreme changes in the sensor values characteristic of the noise induced spikes.
The final conductivity calibration was based on two deployment groupings, due to sensor changes during the voyage. The final calibration for casts 1-13 from the secondary sensor had a standard deviation (S.D) of 0.0010393 PSU, within our target of ‘better than 0.002 PSU’. The final calibration for casts 14-33 from the secondary sensor had a standard deviation (S.D) of 0.0020084 PSU. The standard product of 1dbar binned averaged were produced using data from the secondary sensors.
The final Oxygen calibration from the primary sensor had a S.D of 0.85991 uM. The agreement between the sensor and bottle data was good. Both Oxygen sensors calibrated closely.
The Biospherical photosynthetically active radiation (PAR), Wetlabs Transmissometer, the Wetlabs ECO chlorophyll, and O&A IMU sensors were also installed on the auxiliary A/D channels of the CTD.
The collected data were subsequently processed and archived within the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart. Additional information regarding this dataset may be contained in the Voyage Summary and the CTD Data Processing Report.
Lineage
Original field data.Data processing and quality control by the Marine National Facility Data Acquisition and Processing Group (DAP).
Data processed and archived on 11/04/2018. Data were processed using the new CapPro system.
For this voyage a moving window filter was applied to remove noise spikes from the Pressure, conductivity and oxygen sensor values.
Subjects
Australian Antarctic |
CTD |
CTDs (Conductivity-Temperature-Depth Profilers) |
Chemical Oceanography |
Chlorophyll |
Earth Sciences |
Fluorescence |
Fluorometers |
Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. |
Light Transmission |
Marine National Facility |
NOX monitor |
Nephelometers |
Nitrate |
Oceanography |
Photosynthetically Active Radiation |
Physical Oceanography |
Practical salinity of the water body |
Pressure (measured variable) in the water body exerted by overlying sea water and any medium above it |
Pressure (measured variable) in the water body exerted by overlying sea water only |
Radiation Sensors |
Research Voyage: IN2017_V01 |
Salinity |
Ship: Investigator (RV) |
Southern Ocean |
Temperature of the water body |
Turbidity |
Vessel Data: CTD |
Water Pressure |
Water Temperature |
research vessel |
User Contributed Tags
Login to tag this record with meaningful keywords to make it easier to discover
Identifiers
- Local : 102.100.100/432206
- DOI : 10.25919/yyex-t381
