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Sean Vitousek

Research Oceanographer, Pacific Coastal and Marine Science Center

Science and Products

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DUNEX Modeling Waves, Water Levels, Sediment Transport, and Shoreline Change

Large, collaborative field experiments such as DUNEX leverage observations of the coastal ocean made by multiple academic, agency, and NGO teams, providing the opportunity to grasp a broader picture of the forces responsible for coastal change. Despite deployment of many instruments, it’s impossible to measure everything, everywhere, at all times. Numerical models that represent the physical...
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Pacific Coastal and Marine Science Center, St. Petersburg Coastal and Marine Science Center, Woods Hole Coastal and Marine Science Center
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DUNEX Modeling Waves, Water Levels, Sediment Transport, and Shoreline Change

Large, collaborative field experiments such as DUNEX leverage observations of the coastal ocean made by multiple academic, agency, and NGO teams, providing the opportunity to grasp a broader picture of the forces responsible for coastal change. Despite deployment of many instruments, it’s impossible to measure everything, everywhere, at all times. Numerical models that represent the physical...
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Coastal Storm Modeling System (CoSMoS) for Southern California, v3.0, Phase 2

The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level-rise scenarios, as well as long-term shoreline change and cliff retreat. Resulting projections for future climate scenarios (sea-level rise and storms) provide emergency responders a
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Fire (plus) flood (equals) beach: Coastal response to an exceptional river sediment discharge event

Wildfire and post-fire rainfall have resounding effects on hillslope processes and sediment yields of mountainous landscapes. Yet, it remains unclear how fire–flood sequences influence downstream coastal littoral systems. It is timely to examine terrestrial–coastal connections because climate change is increasing the frequency, size, and intensity of wildfires, altering precipitation rates, and ac
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Reinterpreting the Bruun Rule in the context of equilibrium shoreline models

Long-term (>decades) coastal recession due to sea-level rise (SLR) has been estimated using the Bruun Rule for nearly six decades. Equilibrium-based shoreline models have been shown to skillfully predict short-term wave-driven shoreline change on time scales of hours to decades. Both the Bruun Rule and equilibrium shoreline models rely on the equilibrium beach theory, which states that the beach p
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Global-scale changes to extreme ocean wave events due to anthropogenic warming

Extreme surface ocean waves are often primary drivers of coastal flooding and erosion over various time scales. Hence, understanding future changes in extreme wave events owing to global warming is of socio-economic and environmental significance. However, our current knowledge of potential changes in high-frequency (defined here as having return periods of less than 1 year) extreme wave events ar
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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

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 conditi
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Sediment connectivity: A framework for analyzing coastal sediment transport pathways

Connectivity provides a framework for analyzing coastal sediment transport pathways, building on conceptual advances in graph theory from other scientific disciplines. Connectivity schematizes sediment pathways as a directed graph (i.e., a set of nodes and links). This study presents a novel application of graph theory and connectivity metrics like modularity and centrality to coastal sediment dyn
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Large-scale erosion driven by intertidal eelgrass loss in an estuarine environment

Seagrasses influence local hydrodynamics by inducing drag on the flow and dampening near-bed velocities and wave energy. When seagrasses are lost, near-bed currents and wave energy can increase, which enhances bottom shear stresses, destabilizes sediment, and promotes suspension and erosion. Though seagrasses are being lost rapidly globally, the magnitude of change in sediment stabilization follow
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Sea-level rise exponentially increases coastal flood frequency

Sea-level rise will radically redefine the coastline of the 21st century. For many coastal regions, projections of global sea-level rise by the year 2100 (e.g., 0.5–2 meters) are comparable in magnitude to today’s extreme but short-lived increases in water level due to storms. Thus, the 21st century will see significant changes to coastal flooding regimes (where present-day, extreme-but-rare event
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Steps to develop early warning systems and future scenarios of wave-driven flooding along coral reef-lined coasts

Tropical coral reef-lined coasts are exposed to storm wave-driven flooding. In the future, flood events during storms are expected to occur more frequently and to be more severe due to sea-level rise, changes in wind and weather patterns, and the deterioration of coral reefs. Hence, disaster managers and coastal planners are in urgent need of decision-support tools. In the short-term, these tools
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Blind testing of shoreline evolution models

Beaches around the world continuously adjust to daily and seasonal changes in wave and tide conditions, which are themselves changing over longer time-scales. Different approaches to predict multi-year shoreline evolution have been implemented; however, robust and reliable predictions of shoreline evolution are still problematic even in short-term scenarios (shorter than decadal). Here we show res
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, St. Petersburg Coastal and Marine Science Center

A model ensemble for projecting multi‐decadal coastal cliff retreat during the 21st century

Sea cliff retreat rates are expected to accelerate with rising sea levels during the 21st century. Here we develop an approach for a multi‐model ensemble that efficiently projects time‐averaged sea cliff retreat over multi‐decadal time scales and large (>50 km) spatial scales. The ensemble consists of five simple 1‐D models adapted from the literature that relate sea cliff retreat to wave impacts,
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Doubling of coastal flooding frequency within decades due to sea-level rise

Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

A nonlinear, implicit one-line model to predict long-term shoreline change

We present the formulation, validation, and application of a nonlinear, implicit one-line model to simulate long-term (decadal and longer) shoreline change. The purpose of the implicit numerical method presented here is to allow large time steps without sacrificing model stability compared to explicit approaches, and thereby improve computational efficiency. The model uses a Jacobian-free Newton-K
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Pacific Coastal and Marine Science Center
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Eyes in the Sky: How Satellite Imagery Transforms Shoreline Monitoring From “Data-Poor” to “Data-Rich”

Monitoring coastal changes is important for the millions of people that live along coasts in the U.S., particularly as climate change hastens coastal...

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Coastal Flooding around the Globe Could Double in Decades

A study released in Scientific Reports indicates that the frequency and severity of coastal flooding around the globe could increase rapidly and...

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Disappearing Beaches: Modeling Shoreline Change in Southern California

Using a newly-developed computer model called “CoSMoS-COAST” (Coastal Storm Modeling System – Coastal One-line Assimilated Simulation Tool) scientists...

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