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The application of ensemble wave forcing to quantify uncertainty of shoreline change predictions

February 9, 2021

Reliable predictions and accompanying uncertainty estimates of coastal evolution on decadal to centennial time scales are increasingly sought. So far, most coastal change projections rely on a single, deterministic realization of the unknown future wave climate, often derived from a global climate model. Yet, deterministic projections do not account for the stochastic nature of future wave conditions across a variety of temporal scales (e.g., daily, weekly, seasonally, and interannually). Here, we present an ensemble Kalman filter shoreline change model to predict coastal erosion and uncertainty due to waves at a variety of time scales. We compare shoreline change projections, simulated with and without ensemble wave forcing conditions by applying ensemble wave time series produced by a computationally efficient statistical downscaling method. We demonstrate a sizable (site-dependent) increase in model uncertainty compared with the unrealistic case of model projections based on a single, deterministic realization (e.g., a single time series) of the wave forcing. We support model-derived uncertainty estimates with a novel mathematical analysis of ensembles of idealized process models. Here, the developed ensemble modeling approach is applied to a well-monitored beach in Tairua, New Zealand. However, the model and uncertainty quantification techniques derived here are generally applicable to a variety of coastal settings around the world.

Publication Year 2021
Title The application of ensemble wave forcing to quantify uncertainty of shoreline change predictions
DOI 10.1029/2019JF005506
Authors Sean Vitousek, Laura Cagigal, Jennifer Montaño, Ana Rueda, Fernando Mendez, Giovanni Coco, Patrick L. Barnard
Publication Type Article
Publication Subtype Journal Article
Series Title JGR Earth Surface
Index ID 70223278
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center