ORCID

Abstract

Monitoring sandy shoreline evolution from years to decades is critical to understand the past and predict the future of our coasts. Optical satellite imagery can now infer such datasets globally, but sometimes with large uncertainties, poor spatial resolution, and thus debatable outcomes. Here we validate and analyse satellite-derived-shoreline positions (1984–2021) along the Atlantic coast of Europe using a moving-averaged approach based on coastline characteristics, indicating conservative uncertainties of long-term trends around 0.4 m/year and a potential bias towards accretion. We show that west-facing open coasts are more prone to long-term erosion, whereas relatively closed coasts favor accretion, although most of computed trends fall within the range of uncertainty. Interannual shoreline variability is influenced by regionally dominant atmospheric climate indices. Quasi-straight open coastlines typically show the strongest and more alongshore-uniform links, while embayed coastlines, especially those not exposed to the dominant wave climate, show weaker and more variable correlation with the indices. Our results provide a spatial continuum between previous local-scale studies, while emphasizing the necessity to further reduce satellite-derived shoreline trend uncertainties. They also call for applications based on a relevant averaging approach and the inclusion of coastal setting parameters to unravel the forcing-response spectrum of sandy shorelines globally.

Publication Date

2024-06-06

Publication Title

Scientific Reports

Volume

14

Issue

1

ISSN

2045-2322

Acceptance Date

2024-06-03

Deposit Date

2025-03-19

Funding

This work was done in the framework and funded by Agence Nationale de la Recherche (ANR) grant number ANR-21-CE01-0015. EOF-based climate indices used in this study are publicly available for the period 1980–2017 (National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center; www.cpc.ncep.noaa. gov). We acknowledge the sea level pressure data providers in the ECA &D project (http://www.ecad.eu, Klein Tank et al., 2002) and the Irish Meteorological Service (http://www.met.ie/climate-request/) for the Valentia Observatory data. Contributions by AL and EK are funded by the Deltares’ Strategic Research Programme ‘Seas and Coastal Zones’. GM and TS were supported by the UK Natural Environment Research Council (Grant NE/ M004996/1; BLUE-coast project) and AK was supported by a PhD studentship awarded by CMAR. The University of Plymouth and the Making Space for Sand Project (part of Defra’s Innovative Resilience Programme and managed by Cornwall Council) provided additional financial support for the surveys. This study includes the monitoring site of Truc Vert labelled by the Service National d’Observation (SNO) Dynalit (https://www. dynalit.fr), with Observatoire de la Côte Nouvelle-Aquitaine (OCNA) and Observatoire Aquitain des Sciences de l’Univers (OASU) providing additional financial support for these surveys. The authors would like to thank the five anonymous reviewers for their insightful and constructive comments, which have greatly improved the manuscript.

Keywords

Climate indices, Coastal settings, Interannual variability, Long-term erosion, Sandy coast, Satellite-derived shoreline

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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