Influence of physical drivers on the variability of shoreline position in western South America

Coastal zones play an important role for coastal communities, infrastucture and ecosystems.They are considered as complex systems that are constantly affected by the human activities andthe climate. Due to the configuration of the coastline, some drivers have a greater impact on thecoastline at different times of the year. Here we present a regional evaluation of the shorelinechanges over 27 years (1999-2019) based on satellite observations and reanalysis data. We studythe main hydrodynamic drivers of the coastal variability: the sea level, ocean waves and wind stress(alongshore) on intraseasonal timescales in the western of South America. We analyse the monthlychanges in the shoreline as a linear function of the physical drivers, which are modulated by: theEquatorial Oceanic Kelvin Wave and the coastal trapped wave that have the major variability inthe austral winter at the equator, the Coastal Jet that characterize the wind bursts in the Pisco andCentral Chile region in the austral fall and the extratropical storm activity that module the waves.We found that theses drivers contribute to the most of the variability in the northern region (fromEcuador to the central Peru region 15°S) during June-August, and to the southern region (fromcentral Peru to the central Chile 35°S) during December-February. Our results provide insightinto the effects of physical forcing over the coastline on intraseasonal timescales, which can resultfrom atmospheric and oceanic perturbations from tropical-extratropical teleconnexions, that canbe considered in the context of community resilience.