Journal of Remote Sensing & GIS

Methods and Applications of Remote Sensing for Coastal Bathymetry

Junyu Wang^* Department of Environmental Sciences, Emory University, Atlanta, USA
^*Correspondence: Junyu Wang, Department of Environmental Sciences, Emory University, Atlanta, USA, Email:

Received: 03-Jun-2024, Manuscript No. JGRS-24-26265; Editor assigned: 06-Jun-2024, Pre QC No. JGRS-24-26265 (PQ); Reviewed: 20-Jun-2024, QC No. JGRS-24-26265; Revised: 27-Jun-2024, Manuscript No. JGRS-24-26265 (R); Published: 04-Jul-2024, DOI: 10.35248/2469-4134.24.13.342

Description

Coastal bathymetry, the study of underwater topography along coastal areas, is crucial for various environmental, navigational, and engineering purposes. Traditional methods of bathymetric mapping, such as ship-based sonar surveys, are accurate but often labor-intensive, time-consuming, and limited in spatial coverage. Remote sensing technologies offer a complementary approach, providing efficient, large-scale, and high-resolution data essential for understanding and managing coastal environments. Coastal bathymetry involves mapping the depth and shape of underwater terrain in coastal regions. This information is critical for a range of activities, including marine navigation, coastal engineering, habitat mapping, and environmental monitoring.

Remote sensing methods for coastal bathymetry

Several remote sensing techniques are used for coastal bathymetry, each with unique strengths and limitations. The primary methods include:

Satellite-Derived Bathymetry (SDB): SDB estimates water depths by using multispectral satellite imagery. The technique is based on the principle that light penetration varies with water depth and substrate type. By analyzing the spectral reflectance of different wavelengths (primarily blue and green bands), depth estimations can be made. Satellites such as Landsat, Sentinel-2, and WorldView provide high-resolution imagery suitable for SDB.

Airborne LiDAR Bathymetry (ALB): ALB uses airborne Light Detection and Ranging (LiDAR) technology to measure water depths. A LiDAR sensor emits laser pulses toward the water surface, and the time taken for the pulses to reflect back is used to calculate distances. ALB systems typically use green laser beams, which penetrate water to measure depths. This method provides high-resolution, accurate bathymetric data, especially in clear, shallow waters.

Synthetic Aperture Radar (SAR): SAR uses microwave signals to create high-resolution images of the Earth's surface, including coastal areas. While SAR is more commonly used for terrestrial and oceanographic applications, it can indirectly contribute to bathymetry by monitoring coastal changes, wave patterns, and sediment transport processes. SAR data from satellites like Sentinel-1 and TerraSAR-X can be integrated with other bathymetric data for comprehensive coastal analysis.

Passive optical sensors: Passive optical sensors capture images in the visible and near-infrared spectrum. These sensors rely on sunlight reflection from the sea floor and are used in clear, shallow waters where light penetration is sufficient. High- resolution imagery from satellites like GeoEye and QuickBird enables detailed mapping of coastal features and shallow bathymetry.

Applications of remote sensing in coastal bathymetry

Remote sensing technologies have revolutionized coastal bathymetry, offering numerous applications across various sectors:

Marine navigation: Remote sensing provides updated depth information, helping to identify underwater hazards, such as submerged rocks and sandbars, and ensuring safe passage for vessels. SDB and ALB data are often integrated with nautical charts to enhance navigational safety.

Coastal engineering: Coastal engineering projects, including the construction of ports, harbors, breakwaters, and seawalls, rely on precise bathymetric data. Remote sensing technologies provide high-resolution maps that aid in the design, planning, and monitoring of these structures. Accurate bathymetry ensures the stability and effectiveness of coastal infrastructure.

Environmental monitoring: Coastal ecosystems, such as coral reefs, seagrass beds, and mangroves, depend on accurate bathymetric information for effective monitoring and management. Remote sensing helps in mapping these habitats, assessing their health, and tracking changes over time. Bathymetric data is also important for studying sediment transport, coastal erosion, and the impacts of sea-level rise.

Disaster risk management: Remote sensing plays a vital role in disaster risk management, particularly in predicting and responding to coastal hazards like tsunamis, storm surges, and coastal flooding. Bathymetric data is used to model wave propagation, flood extents, and inundation areas, providing critical information for early warning systems and emergency response planning.

Marine spatial planning: Marine spatial planning involves the allocation of marine space for various uses, including fisheries, tourism, conservation, and resource extraction. Accurate bathymetric maps from remote sensing support informed decision-making, ensuring sustainable use of coastal and marine resources while minimizing conflicts between different stakeholders.

Scientific research: Coastal bathymetry is fundamental for scientific research in oceanography, marine geology, and coastal geomorphology. Remote sensing technologies provide large- scale, high-resolution data that facilitate the study of underwater features, sediment dynamics, and coastal processes. This data enhances our understanding of coastal environments and informs climate change.

Remote sensing technologies have transformed the field of coastal bathymetry, offering efficient, accurate, and comprehensive mapping solutions. Techniques such as satellite-derived bathymetry, airborne LiDAR, and synthetic aperture radar provide valuable data for marine navigation, coastal engineering, environmental monitoring, disaster risk management, marine spatial planning, and scientific research. The integration of remote sensing technologies with traditional methods enhances our ability to understand and manage coastal environments, ensuring the sustainable use of vital water resources. As technology continues to advance, the applications and benefits of remote sensing for coastal bathymetry will only expand, providing even more precise and actionable insights for the protection and management of our coastal regions.