Linear dispersion relation and depth sensitivity to swell parameters: application to synthetic aperture radar imaging and bathymetry.

Valentina Boccia,Antonio Moccia,Alfredo Renga,Simona Zoffoli,Marco D'Errico,Cesare Aragno,Giancarlo Rufino

doi:10.1155/2015/374579

Abstract

Long gravity waves or swell dominating the sea surface is known to be very useful to estimate seabed morphology in coastal areas. The paper reviews the main phenomena related to swell waves propagation that allow seabed morphology to be sensed. The linear dispersion is analysed and an error budget model is developed to assess the achievable depth accuracy when Synthetic Aperture Radar (SAR) data are used. The relevant issues and potentials of swell-based bathymetry by SAR are identified and discussed. This technique is of particular interest for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where traditional SAR-based bathymetric techniques, relying on strong tidal currents, are of limited practical utility.

Highlights

Study and development of new techniques for monitoring and control of coastal regions are a crucial aspect at the international level [1]
The present paper has reviewed the main phenomena related to swell waves propagation that allow underwater bathymetric features to be detected in coastal areas from Synthetic Aperture Radar (SAR) images
The performed analysis has shown that values of water depth up to 40 m can be retrieved in these conditions by using the linear dispersion relation

Summary

Introduction

Study and development of new techniques for monitoring and control of coastal regions are a crucial aspect at the international level [1]. The Scientific World Journal coverage of large areas at relatively low cost, allowing local depth variations and temporal morphodynamical development of seabed in coastal regions to be potentially monitored [2] Those technologies work only with clear water and this represents a significant limit for their applicability [11]. A different approach for SAR-based bathymetric data retrieval has been recently applied to high-resolution SAR data [20] It relies on the variations in wave propagation direction and wavelength that occur when swell waves pass from deep to shallow water [21]. The present paper focuses on SAR-based bathymetry exploiting swell wave propagation This is a promising technique for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where currents are extremely weak and cannot be used to infer bathymetry.

Bathymetric Features on Sea Surface and SAR Imagery

Linear Dispersion Relation for SAR-Based Bathymetry

Discussion

Conclusions