"High-precision traditional technologies such as topographic profiling, boat-based echo sounders and sonar are currently the best available methods for providing accurate bathymetric data, but their use can be limited by cost and time restraints," says Professor Patrick Hesp, head of Environmental Science at Flinders University's College of Science and Engineering.
A recent study showcases the effectiveness of Satellite-Derived Bathymetry (SDB) in mapping nearshore sand movement. This approach offers a more affordable and efficient alternative to conventional methods, especially in shallow, low-wave-energy zones. The research determined the most accurate outcomes by refining combinations of satellite imagery, spectral bands, and empirical techniques.
As part of broader initiatives to track seagrass shifts and coastal changes throughout Adelaide and South Australia, this work capitalizes on optical satellite data. The method's affordability, minimal environmental disturbance, and extensive spatial coverage make it particularly advantageous for surveying remote regions.
"Our findings indicate that using satellite derived bathymetry improves the monitoring of seabed changes, which will improve our ability to map and monitor the dynamic sea floor and aid coastal management," says Joram Downes, a student who recently completed his First-Class Honours thesis in the Beach and Dune Systems (BEADs) Laboratory at Flinders University.
Downes led the study, which fine-tuned satellite-derived bathymetric models for Adelaide's coast by isolating optimal satellite imagery inputs, spectral ranges, and derivation methods.
"Satellite derived bathymetry will supplement existing methods of data collection, filling in gaps in data where seafloor elevation remains unknown" says Associate Professor David Bruce, an expert in remote sensing at Flinders University, and primary supervisor of Mr Downes.
Supported in part by the Coast Protection Board, the study assessed over 100 bathymetric derivation methods, calibrated against a dataset exceeding 1 million ground observations. The findings identified the PlanetScope SuperDove constellation as offering the best input spectral bands for accuracy.
Additionally, researchers employed newly acquired drone-mounted bathymetric LiDAR. Associate Professor Graziela Miot da Silva, who integrates such tools in coastal monitoring, welcomed the study's outcomes.
"It was exciting to see these technologies working seamlessly together, especially the LiDAR that captured excellent data in shallow waters which closely aligned with the sonar dataset, and provided a precision method to correlate with the satellite-based bathymetry," says Associate Professor Miot da Silva.
"This research not only optimises satellite derived bathymetry for use in the Gulf St Vincent, but it also provides valuable insights into how the number of input bands, their spatial resolution and their specific spectral properties influence the quality of satellite-derived bathymetry datasets," says Mr Downes.
Research Report:Optimising Satellite-Derived Bathymetry Using Optical Imagery over the Adelaide Metropolitan Coast
Related Links
College of Science and Engineering, Flinders University
Earth Observation News - Suppiliers, Technology and Application
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