This record describes the CTD data collected on Investigator voyage IN2023_V07, titled: "SWOT-ACC: smaller scales of the Antarctic Circumpolar Current in a meander south of Tasmania." The voyage took place between November 15, 2023 and December 20, 2023 (AEST), departing from Hobart and returning to Hobart.
The primary focus of this voyage was to enhance our ability to observe and comprehend the effects of small-scale motions (ranging from 10 to 100 km) on the dynamics of the Antarctic Circumpolar Current (ACC). The groundbreaking Surface Water Ocean Topography (SWOT) satellite mission will provide unprecedented measurements of sea surface height over a wide area with substantially improved spatial resolution compared to traditional altimeters. While SWOT will offer unparalleled coverage in both space and time, it is crucial to obtain in situ subsurface ocean measurements to validate the satellite observations and establish the connection between small-scale variability in sea surface height and subsurface ocean circulation and dynamics.
Data for 111 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 primary sensor had a standard deviation (SD) of 0.0012454 PSU, within our target of ‘better than 0.002 PSU’. The standard product of 1-decibar binned averages were produced using data from the primary sensors.
The dissolved oxygen data (primary) calibration fit had a SD of 0.78388 μM. The agreement between the CTD and bottle data was good.
Additional sensors include: SUNA Nitrate, Altimeter (Tritech PA500), Transmissometer (Wetlabs CStar), CDOM, Chlorophyll-a, Scattering (Wetlabs ECO FLCDRTD) were installed on the auxiliary A/D channels of the CTD.
The collected data were processed (quality-controlled), and subsequently 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 Data Processing Report.
