RV Investigator Voyage IN2025_V05 ADCP Data

Updated: 2026-07-31

This record describes the Acoustic Doppler Current Profiler (ADCP) data collected from the Marine National Facility RV Investigator voyage IN2025_V05, titled: "Eruption, destruction, and seafloor ecosystem recovery – Tonga's 2022 eruption of the century." The voyage took place between August 10, 2025 and October 01, 2025 (AEST), departing from Hobart and returning to Brisbane. The ADCP was run for most of the voyage, though it was turned off when EM712 and EM2040 Mk2 surveys were being performed to avoid creating interference in the multibeam data. ADCP data were collected using the University of Hawaii Data Acquisition System (UHDAS) and post-processed using the Common Ocean Data Access System (CODAS). Documentation for these systems can be found in (Hummon, 2009-2021). The RDI Ocean Surveyor 150kHz ADCP, RDI Ocean Surveyor 75kHz ADCP and RDI Ocean Surveyor 38kHz ADCP were run in narrowband mode. External triggering was used. The drop keel was set at 2 m below the hull for the duration of the voyage. The nominal transducer depth is set to 6 metres; any additional changes will need to be applied by the user if they believe it is required. Bottom tracking was run for the first hour of the voyage on the OS150nb to aid in calibrations. The following processing issues were encountered for this dataset On this voyage, it was discovered the OS75 would report signal below the bottom, which is suspected to be electrical interference. This data set was split into two cruises to accommodate for changes in positioning systems during acquisition and subsequently reprocessed using the Seapath. For more information please see the Processing Report (linked below). This dataset was processed (quality-controlled), and then archived by the CSIRO National Collections and Marine Infrastructure (NCMI) Information and Data Centre (IDC).