Manly Hydraulics Laboratory Waverider buoys

Researchers: AODN Data Manager (Distributes) ,  Data Officer (Distributes) ,  Data Officer (Distributes)

Brief description Manly Hydraulics Laboratory (MHL) part of the NSW Office of Environment and Heritage (OEH) (function now assumed by NSW Department of Planning, Industry and Environment (DPIE)) operates a system of Waverider buoys off the NSW coastline. The buoys measure wave height and other wave statistics such as wave period on a continuous real-time basis. Some of the buoys are also capable of measuring wave direction and sea surface temperature (discoverable in a separate collection: Manly Hydraulics Laboratory Waverider buoys - Sea surface temperature data - https://catalogue-imos.aodn.org.au:443/geonetwork/srv/api/records/81c5f192-d4af-4dfe-a660-af15ae46a22a). This metadata record is a parent record describing the MHL Waverider system as a whole. The child metadata records describe each deployment of the buoy in more detail with links to downloadable data. The data is gathered by the Waverider system developed by the Dutch company, Datawell. The Waverider system uses an accelerometer mounted in a loose tethered buoy (0.7 or 0.9m in diameter) to measure the vertical accelerations of the buoy as it moves with the water surface. The accelerations are integrated twice within the buoy and the displacement signal so obtained is then transmitted to a shore station where it is processed to provide wave data statistics. The wave data is stored on the receiving station PC before routine transfer to Manly Hydraulics Laboratory via email. The wave direction capable Waverider buoys utilise a heave-pitch-roll sensor, two fixed X and Y accelerometers and a three axis fluxgate compass to measure both vertical and horizontal motion. An on-board processor converts the buoy motion to three orthogonal (vertical, north-south, east-west) translation signals that are transmitted to the shore station. The data originally represented by this metadata record has been reformatted and now forms part of the National Wave Archive, and is accessible from that collection - https://catalogue-imos.aodn.org.au:443/geonetwork/srv/api/records/2807f3aa-4db0-4924-b64b-354ae8c10b58. The original data has been archived (contact IMOS for access).

Lineage Statement: Prior to a six to eight month deployment, the operation of a Waverider buoy is tested on the Manly Hydraulics Laboratory Waverider buoy calibration rig to ensure it meets the manufacturers operational specifications. Wave data are transmitted from the Waverider buoy to a shore station where it is processed to produce wave data statistics. The recorded bursts of wave data (normally 34 minutes long starting on the hour) are digitised at 0.5-second intervals (or 0.78-second intervals for a Directional Waverider buoy) and the data are conditioned to remove any erroneous data points. The data are then analysed using two procedures: zero crossing analysis and spectral analysis. The wave data is routinely quality controlled (usually twice per week) using a wave data quality control program developed by Manly Hydraulics Laboratory. The wave data statistics are examined and raw data and spectral plots are viewed by an experience operator to check for any anomalies. Wave statistics from adjacent Waverider stations are also compared to assist in the identification of any "out of range" values. Erroneous wave data records are removed and good quality data is flagged as "Quality Controlled" in the Manly Hydraulics Laboratory wave database.

Lineage Statement: The data originally represented by this metadata record has been reformatted and now forms part of the National Wave Archive, and is accessible from that collection - https://catalogue-imos.aodn.org.au/geonetwork/srv/en/metadata.show?uuid=2807f3aa-4db0-4924-b64b-354ae8c10b58 (January 2019). The original data has been archived (contact IMOS for access).

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Data collection funded by NSW Office of Environment and Heritage (OEH)

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Waverider buoy system and data management undertaken for OEH by NSW Public Works Manly Hydraulics Laboratory

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Australia’s Integrated Marine Observing System (IMOS) is enabled by the National Collaborative Research Infrastructure Strategy (NCRIS). It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as Lead Agent.

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Australian Ocean Data Network (AODN). AODN is supported by the Australian Government.