Directional wave buoy data measured near Campbell Island, New Zealand

Brief description

The New Zealand Defence Force (NZDF) has established a permanent wave observation station near Campbell Island, south of New Zealand (52 45.71 S, 169 02.54E). The site was chosen for logistical convenience and its unique location adjacent to the highly energetic Southern Ocean; allowing instrumentation typically deployed on the continental shelf to be used in this rarely observed southern environment. From February 2017, a Triaxys Directional Wave Buoy was moored in 147 m depth, some 17 km to the south of the island, with satellite telemetry of the 2D wave spectra at 3-hourly intervals. To date there have been three deployments on locations, yielding some 784 days of data. Validation of the measured significant wave height against co-located satellite altimeter observations suggests that the predominant wave directions are not attenuated by the island. The data provide a valuable record of the detailed wave spectral characteristics from one of the least-sampled parts of the Global Ocean. This and future data will also be accessible via the "Waverider buoys Observations - Australia - delayed (National Wave Archive)" collection available through the Australian Ocean Data Network Portal (https://imos.aodn.org.au/imos123/home?uuid=%202807f3aa-4db0-4924-b64b-354ae8c10b58), the main repository for marine data in Australia. The data represented by this metadata record is a snapshot of the NZDF data at the time of this publication (03/08/2021), and has been assigned a DOI and will be maintained in perpetuity by the AODN.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: A standard Triaxys Directional Wave Buoy has been used for the programme, with a 20-minute sampling regime at 3-hourly intervals. Raw and processed data are stored on-board for manual download at the annual servicing, while the 1D and 2D spectral files are transmitted by Iridium telemetry in near real-time. For the first deployment (08/02/17 – 27/07/17) a factory-supplied 15 m rubber bungy cord was attached to the buoy, with 185 m of 12 mm Dyneema rope (and midwater buoyancy units) used to anchor the buoy to 600 kg of 32 mm stud-link chain. The mooring revision for the second deployment (02/03/18 – 19/06/19) deleted the bungy, as this was the likely failure point under repeated fatigue. Instead, a 220 m length of 12 mm Dyneema was used, with midwater buoyancy set at 100 m above the seabed to create a false bottom, and improved chain weight dampening at the seabed.The third deployment of the mooring was conducted on the 27th of November 2019.

Notes

Credit
New Zealand Defence Force (NZDF)