Climate-driven waterline variability along the North American West Coast

By: , and 

Links

Abstract

Sandy coasts are highly dynamic environments shaped by a myriad of hydro-sedimentary processes operating across various spatio-temporal scales. From seasonal to centennial timescales, sandy beach dynamics are strongly influenced by climate variability expressed in various forms, including seasonal cycles, climate modes (e.g., El Niño Southern Oscillation (ENSO)), and global warming. Satellite-based methods enable the observation of coastlines with unprecedented spatial and temporal coverage. However, over the past decade, as these methods have matured, coastal change studies have predominantly focused on long-term trends rather than on climate-driven cycles of shoreline change. In this study, we utilize a large dataset of monthly-sampled time series of waterline positions along the Pacific Coast of the United States and Baja California, Mexico. From these time series, we derived information on long-term trends and seasonal cycles of waterline change. Our analysis reveals clear contrasts in seasonal patterns of waterline variability across the study area, with greater amplitudes observed at higher latitudes. A shift in the dominant dynamics is evident in Southern Baja California, where shoreline variability is more influenced by intertropical dynamics and sea-level anomalies than by wave energy modulation, which dominates further north. ENSO is found to induce contrasting responses of the waterline along the study area. During El Niño events, shoreline retreat is observed in subtropical regions, while La Niña winters drive waterline retreat in higher latitudes, with southern regions either remaining stable or advancing.

Suggested Citation

Graffin, M., Almar, R., Bergsma, E., Boucharel, J., Vitousek, S., Taherkhani, M., and Ruggiero, P., 2025, Climate-driven waterline variability along the North American West Coast, Coastal Dynamics 2025, v. 1, Aveiro, Portugal, April 7-11, 2025, p. 487-492, https://doi.org/10.1007/978-3-032-15473-6_74.

Study Area

Publication type Conference Paper
Publication Subtype Abstract or summary
Title Climate-driven waterline variability along the North American West Coast
DOI 10.1007/978-3-032-15473-6_74
Volume 1
Publication Date March 05, 2026
Year Published 2025
Language English
Publisher Springer
Contributing office(s) Pacific Coastal and Marine Science Center
Description 6 p.
First page 487
Last page 492
Conference Title Coastal Dynamics 2025
Conference Location Aveiro, Portugal
Conference Date April 7-11, 2025
Country Mexico, United States
State Baja California, California, Oregon, Washington
Other Geospatial Pacific Coast
Additional publication details