RV Investigator Voyage IN2023_V04 CTD Data

This record describes the Conductivity-Temperature-Depth (CTD) data collected from the Marine National Facility RV Investigator voyage IN2023_V04, titled: "International nutrient inter-comparison study in the Southern Ocean: quantifying and identifying the causes of differences in dissolved inorganic nutrient datasets between global seagoing laboratories - Phase 2". The voyage took place between June 5 and June 18, 2023 departing from Hobart (TAS) and returning to Hobart.

Data for 10 CTD deployments were acquired using the Sea‐Bird SBE9+V2 CTD unit #24 (S/N 1332), fitted with 36 twelve‐litre bottles on the rosette sampler. Sea‐Bird‐supplied calibration factors were used to compute the pressures and preliminary conductivity values. CSIRO‐supplied calibrations were applied to the temperature data. The data were subjected to automated QC to remove spikes and out‐of‐range values.

The final conductivity calibration was based on a single deployment grouping. The final calibration from the secondary sensor had a standard deviation (SD) of 0.0010067 PSU, well within our target of ‘better than 0.002 PSU’. The standard product of 1‐decibar binned averages were produced using data from the secondary sensors.

The dissolved oxygen data calibration fit had a SD of 0.92376 μM. The agreement between the CTD and bottle data was good.

The collected data were subsequently processed (quality-controlled), and archived by the CSIRO National Collections and Marine Infrastructure (NCMI) Information and Data Centre (IDC). Additional information regarding this dataset may be contained in the Voyage Summary and the CTD Data Processing Report.