Geomorphometric analysis of nearshore sedimentary bedforms from high-resolution multi-temporal satellite-derived bathymetry

Abstract

Monitoring sedimentary bedforms is crucial for coastal planning projects. Detailed shallow bathymetry is a fundamental tool for analyzing sedimentary bedforms, however it is often unavailable due to fieldwork limitations. This study utilizes high resolution satellite-derived bathymetry (SDB) for monitoring nearshore bedforms at the northern coast of Chania (Crete, Greece). A random forest technique is employed for training and predicting SDB using two types of multispectral satellite imagery along with ground-truth sonar data. SDB maps have an error of 0.5 meter and allowed for identifying nearshore crescentic bar systems which are the result of local hydrodynamic activity. Bedform metrics were extracted by applying geomorphological indices. Crescentic bars found to be changing shape on annual scale. Nearshore seafloor with soft substrate, changes rapidly and temporal SDB mapping is a fundamental approach for effective coastal monitoring. Multi-temporal SDB maps provide observational evidence about local hydrodynamics which is beneficial in coastal engineering applications.

Keywords:

• Coastal geomorphology
• nearshore seafloor
• bedforms
• satellite derived bathymetry
• multispectral imagery

Acknowledgment

Satellite imagery was kindly provided by the European Space Agency (ESA), as part of the successful proposal evaluation regarding the Project ID: 63719. Furthermore, we would like to thank the Hellenic Navy Hydrographic Service for providing the multibeam-bathymetry data for the Heraklion area. This study is part of the ACTYS project (https://actys.ims.forth.gr/) that has received funding from a 2020 FORTH-Synergy Grant.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data available on request from the authors.

Additional information

Funding

This work was supported by a FORTH-Synergy grant and satellite imagery was provided by ESA after successful proposal evaluation (Project Id: 63719).