The Lucinda Jetty Coastal Observatory (LJCO ) is located on the end of the 5.8 km long Lucinda Jetty (18.52 S, 146.39 E) in the coastal waters of the Great Barrier Reef World Heritage Area close to the Herbert River Estuary and the Hinchinbrook Channel in Queensland.
The observatory was established in 2009. Early deployments in 2010 were semi-operational – during this time instruments were tested and anti-fouling strategies for the submerged instruments as well as calibration and maintenance routines established. In February 2011 tropical cyclone Yasi caused severe structural damage to the Lucinda Jetty and resulted in the complete loss of the enclosure. It took over 12 months for the Jetty to be restored to safe working order. A new observatory enclosure was finally installed in April 2013 while routine data acquisitions commenced in December 2013.
At LJCO above and in-water optical measurements are acquired with the objective to support satellite validation and remote sensing algorithm development. Currently, LJCO is the only southern-hemisphere ocean colour validation site integrated into NASA’s AERONET-OC global network of ground-based radiometers and one of a few sites globally that combines the acquisition of both atmospheric and in-water optical measurements to help unravel the inaccuracies in remotely-sensed satellite ocean colour products due to the optical complexity of coastal waters and the overlying atmosphere. At LJCO these measurements compromise of:
Above-water optical measurements:
- Water-leaving radiance and atmospheric observations for retrieving aerosol optical properties using an autonomous CIMEL SeaPRISM radiometer that is integrated into NASA’s global Aeronet-OC network,
- Hyper-spectral measurements of the down-welling irradiance using a Satlantic HyperOCR.
In-water optical measurements:
- Conductivity, temperature, pressure, dissolved oxygen, chlorophyll fluorescence and turbidity using a WETLabs WQM,
- Coloured dissolved organic matter fluorescence using a WETLabs WETStar fluorometer,
- Particulate and dissolved spectral absorption and attenuation coefficients using a WETLabs AC-S and,
- Total backscattering coefficients using a WETLabs BB9 radiometer.
Meteorological and sea state measurements:
- Barometric pressure, relative humidity, air temperature, wind speed and wind direction is recorded by a Vaisala WXT520 weather transmitter,
- Wave height and water temperature are measured with a Campbell Scientific submersible pressure transducer that is used to keep the in-water optical instruments at a constant depth.
The site gets serviced ideally on fortnightly basis when in-water instruments are rotated and replaced and surface water samples are collected time-optimized for satellite overpasses. Water samples are filtered in the laboratory and subsequently analysed for phytoplankton pigments by High Performance Liquid Chromatography (HPLC). In addition, concentrations of total suspended solids are determined by gravimetric analysis, while algal, non-algal and coloured dissolved organic matter (CDOM) spectral absorption is measured, using a dual-beam UV/VIS spectrophotometer fitted with an integrated sphere.
Since early 2013 the Ocean Colour Sub-Facility also supports the Marine Monitoring Program of the Great Barrier Reef Marine Park Authority by deploying passive pesticide samplers helping to monitor photosystem II herbicide concentrations. Samplers are either deployed monthly or bi-monthly during the wet season before they are returned to the National Centre for Environmental Toxicology for further analysis.
IMOS acknowledges Queensland Sugar Ltd for the use of the jetty on which the Lucinda Jetty Coastal Observatory is located.