Confronting turbidity, the major challenge for satellite-derived coastal bathymetry

Area of Science:

• Marine Geoscience
• Remote Sensing
• Coastal Ecology

Background:

• Accurate seafloor morphology mapping is essential for understanding coastal ecosystem function and assessing marine activities.
• Satellite-derived bathymetry (SDB) offers a valuable tool for creating bathymetric maps crucial for coastal hazard and climate change impact assessment.
• Existing SDB methods face limitations in turbid waters, restricting their application in many vulnerable coastal zones.

Purpose of the Study:

• To develop and demonstrate a comprehensive, operational bathymetric mapping method using satellite data adaptable to various environmental conditions.
• To overcome the limitations of SDB in turbid waters by integrating water quality information and multi-temporal compositing.
• To assess the accuracy and applicability of the developed method across diverse geographic regions and optical water types.

Main Methods:

• Utilized twin Sentinel-2A/B satellites for data acquisition.
• Integrated satellite-derived water quality information with a multi-temporal compositing technique.
• Developed an automated compositing method to mitigate turbidity impacts, infer maximum detectable depth, and exclude optically deep waters.

Main Results:

• Successfully mapped detailed bathymetry down to 30 meters with a 10-meter spatial resolution.
• Achieved median errors of less than 1 meter when compared against high-resolution lidar surveys.
• Demonstrated effectiveness across a wide range of conditions along the Caribbean and eastern U.S. coast.

Conclusions:

• The adopted model provides reliable bathymetry even in areas with non-ideal water clarity, expanding SDB applicability.
• The method is scalable and can be extended for bathymetric mapping at local, regional, and national levels.
• This advancement supports more comprehensive monitoring of coastal ecosystems and assessment of marine activities.