RV Investigator Voyage IN2025_V01 Triaxus (undulating CTD) Data

Updated: 2026-09-30

This record describes the data (CTD, Dissolved Oxygen, Transmissometer, PAR, ECO Triplet, Nitrate, Fluorescence and LOPC) collected using the towed TRIAXUS platform on Investigator voyage IN2025_V01, titled: "Collaborative Australian Postgraduate Sea Training Network (CAPSTAN)." The voyage took place between March 08, 2025 and March 17, 2025 (AEST), departing from Hobart and returning to Hobart. 1 Triaxus tow was conducted. The tow was conducted as a training experience for student participants of the CAPSTAN voyage. Pressure, conductivity, temperature, and dissolved oxygen data were gathered from duplicate sensors using a Seabird SBE9plus CTD. Also carried on the Triaxus hull were a cosine Photosynthetically Active Radiation (PAR) sensor, a transmissometer, and an ECO Triplet (optical backscatter. Acquisition was not stopped and started at the beginning of undulation, and the data had to undergo extra post-processing due to this. Tow 1 was stopped earlier than planned due to a battery issue on the Triaxus. See Appendix A.1 for definitions and example usage of common terms employed here and throughout this report to describe Triaxus tow components and their associated data. Pressure, conductivity, temperature, and dissolved oxygen sensor data were converted to calibrated units. Spikes and out-of-range values were removed, and primary sensor data were compared to secondary sensor data. PAR, transmissometer, and ECO triplet (Chlorophyll, CDOM, OBS) data were combined into the dataset. Published data have been grouped into 1-decibar bins. Data from the secondary CTD sensors were assessed to be more reliable as there was a calibration issue observed with the primary Oxygen data, so the final dataset uses the secondary CTD sensor values in the default data variables (i.e., variables without “_2” appended). On this voyage the tow was recorded in a single file. The published data consist of: • along-track time-series data for the tow • synthetic interpolated vertical casts for each undulation peak and trough of the tow • interpolated sectional plots of various sensor data taken from along-track time-series data for the tow 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.