Chris (he/him/his), is a coastal oceanographer with expertise in measuring and modeling sediment transport and coastal morphology changes.
Professional Experience
Research Oceanographer, U.S. Geological Survey, Menlo Park, CA and Woods Hole, MA, 1999 – present.
Affiliate Faculty, Ocean Engineering, University of New Hampshire, Durham, NH, 2009 – present
Guest Investigator, Applied Ocean Physics & Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, 2011 – present
Senior Research Scientist, Commonwealth Scientific and Industrial Research
Education and Certifications
Ph.D. Geological Oceanography, University of Washington, Seattle, Washington 1995
M.S. Geological Oceanography, University of Washington, Seattle, Washington 1982
A.B. Economics and Environmental St
Science and Products
Remote Sensing Coastal Change
Using Video Imagery to Study Storm Events at Pea Island National Wildlife Refuge
Using Video Imagery to Study Head of the Meadow Beach
DUNEX Hazards at Pea Island
DUNEX Aerial Imagery of the Outer Banks
DUNEX Pea Island Experiment
USGS DUNEX Operations on the Outer Banks
Using Video Imagery to Study Marconi Beach
Sea Floor Stress and Sediment Mobility Database
Coastal Model Applications and Field Measurements- Field Measurements and Model Applications
Coastal Model Applications and Field Measurements- Advances in Instrumentation
Coastal Model Applications and Field Measurements- Ocean Model Contributions
Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, Massachusetts in March 2023, U.S. Geological Survey Field Activity 2023-012-FA
Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Head of the Meadow Beach, Truro, Massachusetts in March and April 2023, U.S. Geological Survey Field Activity 2023-011-FA
Topographic, bathymetric, multispectral, vegetation, sediment, and supporting GPS data collected on North Core Banks, Cape Lookout National Seashore, North Carolina in October 2022, U.S. Geological Survey Field Activity 2022-034-FA
Meteorological data from Pea Island National Wildlife Refuge, North Carolina, 9/13/2021 to 10/24/2021
Aerial photogrammetry data and products of the North Carolina coast
Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, MA in March 2022, U.S Geological Survey Field Activity 2022-014-FA
Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Head of the Meadow Beach, Truro, MA in March 2022, U.S. Geological Survey Field Activity 2022-015-FA
Grain-size analysis data of sediment samples from the beach and nearshore environments at the Pea Island National Wildlife Refuge DUNEX site, North Carolina in 2021
DUNEX topographic, bathymetric, and supporting GPS data collected in Pea Island National Wildlife Refuge, North Carolina 2020-2021
Aerial Imagery of the North Carolina Coast: 2020-05-08 to 2020-05-09
Aerial Imagery of the North Carolina Coast: 2020-02-08 to 2020-02-09
U.S. Geological Survey simulations of hydrodynamics and morphodynamics at Matanzas, FL during Hurricane Matthew (2016) and at Fire Island, NY during Hurricane Sandy (2012)
Incorporating wave climate complexity into modeling lower shoreface morphology and transport
Modeling total water level and coastal change at Pea Island, North Carolina, USA
Contributions to uncertainty in runup forecasts
Processes controlling coastal erosion along Cape Cod Bay, MA
Temporal variability of runup and total water level on Cape Cod sandy beaches
Sound-side inundation and seaward erosion of a barrier island during hurricane landfall
CoastalImageLib: An open-source Python package for creating common coastal image products
Shoaling wave shape estimates from field observations and derived bedload sediment rates
Human-in-the-Loop segmentation of earth surface imagery
Modeling of barrier breaching during Hurricanes Sandy and Matthew
Modeling morphodynamics of coastal response to extreme events: What shape are we in?
Processing coastal imagery with Agisoft Metashape Professional Edition, version 1.6—Structure from motion workflow documentation
IntroductionStructure from motion (SFM) has become an integral technique in coastal change assessment; the U.S. Geological Survey (USGS) used Agisoft Metashape Professional Edition photogrammetry software to develop a workflow that processes coastline aerial imagery collected in response to storms since Hurricane Florence in 2018. This report details step-by-step instructions to create three-dimen
COAWST Modeling System v3.4
Science and Products
- Science
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Remote Sensing Coastal Change
We use remote-sensing technologies—such as aerial photography, satellite imagery, structure-from-motion (SfM) photogrammetry, and lidar (laser-based surveying)—to measure coastal change along U.S. shorelines.Using Video Imagery to Study Storm Events at Pea Island National Wildlife Refuge
Two video cameras were temporarily mounted on a dune at Pea Island National Wildlife Refuge on the Outer Banks of North Carolina.Using Video Imagery to Study Head of the Meadow Beach
Two video cameras are mounted on a bluff near Head of the Meadow Beach, Cape Cod National Seashore, North Truro, MA. One camera looks alongshore toward the north-northeast, and the second looks directly offshore (northeast). The cameras are part of a U.S. Geological Survey research project to study the beach and nearshore environment shared by beachgoers, shorebirds, seals, and sharks. The work is...DUNEX Hazards at Pea Island
DANGER! INSTRUMENTS IN THE WATER AT PEA ISLAND!DUNEX Aerial Imagery of the Outer Banks
The During Nearshore Event Experiment (DUNEX) project is a large collaborative scientific study focusing on understanding the consequences of coastal storms on the morphology of coastal ecosystems. By flying large sections of the coast and collecting still images using structure from motion (SfM) techniques, we hope to contribute high resolution (20cm) elevation maps for time series comparisons...DUNEX Pea Island Experiment
The DUring Nearshore Event eXperiment (DUNEX) is an aggregation of multiple scientific organizations collaborating to increase understanding of nearshore processes. The U.S. Geological Survey (USGS) has chosen Pea Island National Wildlife Refuge as a study location to investigate and characterize the magnitude and timing of changes to coastal morphology (i.e., dunes, shorelines), bathymetry, and...USGS DUNEX Operations on the Outer Banks
DUring Nearshore Event eXperiment (DUNEX) is a multi-agency, academic, and non-governmental organization (NGO) collaborative community experiment designed to study nearshore coastal processes during storm events. The experiment began in 2019 and is scheduled for completion in the fall of 2021. USGS participation in DUNEX will contribute new measurements and models that will increase our...Using Video Imagery to Study Marconi Beach
Two video cameras are mounted on a bluff above Marconi Beach, Cape Cod National Seashore, Wellfleet, MA. One camera looks alongshore toward the northeast, and the second looks directly offshore (east). The cameras are part of a U.S. Geological Survey research project to study the beach and nearshore environment shared by beachgoers, shorebirds, seals, and sharks. The work is being conducted under...Sea Floor Stress and Sediment Mobility Database
The U.S. Geological Survey Sea Floor Stress and Sediment Mobility Database contains estimates of wave-current bottom stress and sediment mobility for the U.S. Atlantic and Gulf Coast continental shelf regions.Coastal Model Applications and Field Measurements- Field Measurements and Model Applications
Several components of this project are applications to evaluate the model against critical field measurements or to test new model components. Data from field measurements is described in our publications and available in our databases.Coastal Model Applications and Field Measurements- Advances in Instrumentation
Ongoing acquisition of new instruments and development of analytical methods provides us with the means to make better observations of coastal ocean processes. The measurements provide us with insight and data for critical evaluation of model performance. Advances in a range of measurement capabilities, including bottom stress, sediment erodibility, water properties and nutrient concentrations...Coastal Model Applications and Field Measurements- Ocean Model Contributions
The U.S. Geological Survey (USGS) and Woods Hole Oceanographic Institution (WHOI) led a project funded by the National Oceanographic Partnership Program (NOPP) with support from the Office of Naval Research (ONR) and the National Science Foundation (NSF), to develop a community sediment-transport modeling system (CSTMS). - Data
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Topographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, Massachusetts in March 2023, U.S. Geological Survey Field Activity 2023-012-FA
The data in this release re-map the beach and nearshore environment at Marconi Beach in Wellfleet, MA and provide updated environmental context for the 2021 CoastCam installation that looks out at the coast shared by beachgoers, shorebirds, seals, and sharks. This is related to the field activity 2022-014-FA and a collaboration with the National Park Service at Cape Cod National Seashore to monitoTopographic and bathymetric data, structure from motion imagery, and ground control data collected at Head of the Meadow Beach, Truro, Massachusetts in March and April 2023, U.S. Geological Survey Field Activity 2023-011-FA
The data in this release re-map the beach and nearshore environment at Head of the Meadow Beach in Truro, MA and provide updated environmental context for the 2020 CoastCam installation that looks out at the coast shared by beachgoers, shorebirds, seals, and sharks. This is related to the field activity 2022-015-FA and a collaboration with the National Park Service at Cape Cod National Seashore toTopographic, bathymetric, multispectral, vegetation, sediment, and supporting GPS data collected on North Core Banks, Cape Lookout National Seashore, North Carolina in October 2022, U.S. Geological Survey Field Activity 2022-034-FA
These data map in high detail surficial cross-sections of North Core Banks, a barrier island in Cape Lookout National Seashore, NC, in October 2022. U.S. Geological Survey field efforts are part of an interagency agreement with the National Park Service to monitor the recovery of the island from Hurricanes Florence (2018) and Dorian (2019). Three sites of outwash, overwash, and pond formation wereMeteorological data from Pea Island National Wildlife Refuge, North Carolina, 9/13/2021 to 10/24/2021
Meteorological data were collected as part of the DUring Nearshore Event eXperiment (DUNEX) on Pea Island National Wildlife Refuge in North Carolina during 2021. The DUNEX project is a collaborative, multi-agency experiment designed to provide comprehensive measurements of storm-induced processes on coastal habitats. The overarching goals of this study are to understand oceanographic processes andAerial photogrammetry data and products of the North Carolina coast
This data release presents structure-from-motion (SfM) products derived from aerial imagery collected along the North Carolina coast in response to storm events and the recovery process. U.S. Geological Survey (USGS) researchers use the aerial imagery and products to assess future coastal vulnerability, nesting habitats for wildlife, and provide data for hurricane impact models. This research is pTopographic and bathymetric data, structure from motion imagery, and ground control data collected at Marconi Beach, Wellfleet, MA in March 2022, U.S Geological Survey Field Activity 2022-014-FA
The data in this release map the beach and nearshore environment at Marconi Beach in Wellfleet, MA and provide updated environmental context for the 2021 CoastCam installation that looks out at the coast shared by beachgoers, shorebirds, seals, and sharks. This is related to the field activity 2022-014-FA and a collaboration with the National Park Service at Cape Cod National Seashore to monitor tTopographic and bathymetric data, structure from motion imagery, and ground control data collected at Head of the Meadow Beach, Truro, MA in March 2022, U.S. Geological Survey Field Activity 2022-015-FA
These data map the beach and nearshore environment at Head of the Meadow Beach in Truro, MA, providing updated regional context for the 2019 CoastCam installation. CoastCam CACO-01 are two video cameras aimed at the beach that view the coast shared by beachgoers, shorebirds, seals, and sharks. These data were collected as part of field activity 2022-015-FA and a collaboration with the National ParGrain-size analysis data of sediment samples from the beach and nearshore environments at the Pea Island National Wildlife Refuge DUNEX site, North Carolina in 2021
These data provide grain-size measurements from sediment samples collected as part of the USGS DUring Nearshore Event eXperiment (DUNEX) site on Pea Island National Wildlife Refuge, NC. DUNEX is a multi-agency, academic, and non-governmental organization collaborative community experiment designed to study nearshore coastal processes during storm events. USGS participation in DUNEX will contributeDUNEX topographic, bathymetric, and supporting GPS data collected in Pea Island National Wildlife Refuge, North Carolina 2020-2021
The data in this release characterize the beach and nearshore environment in Pea Island National Wildlife Refuge, NC at the USGS DUring Nearshore Event eXperiment (DUNEX) site and Basnight Bridge. Data include GPS surveys, reference points, and ground control points; imagery and structure-from-motion products; bathymetry data, and merged topographic and bathymetric grids. To cite a specific dataAerial Imagery of the North Carolina Coast: 2020-05-08 to 2020-05-09
The U.S. Geological Survey (USGS) Remote Sensing Coastal Change (RSCC) project collects aerial imagery along coastal swaths, in response to storm events, with optimized endlap/sidelap and precise position information to create high-resolution orthomosaics, three-dimensional (3D) point clouds, and digital elevation/surface models (DEMs/DSMs) using Structure-from-Motion (SfM) photogrammetry methods.Aerial Imagery of the North Carolina Coast: 2020-02-08 to 2020-02-09
The U.S. Geological Survey (USGS) Remote Sensing Coastal Change (RSCC) project collects aerial imagery along coastal swaths, in response to storm events, with optimized endlap/sidelap and precise position information to create high-resolution orthomosaics, three-dimensional (3D) point clouds, and digital elevation/surface models (DEMs/DSMs) using Structure-from-Motion (SfM) photogrammetry methods.U.S. Geological Survey simulations of hydrodynamics and morphodynamics at Matanzas, FL during Hurricane Matthew (2016) and at Fire Island, NY during Hurricane Sandy (2012)
The Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST Warner and others, 2019; Warner and others, 2010) model was used to simulate ocean circulation, waves, and sediment transport to study barrier island breaches that occurred during Hurricane Matthew (2016) near Matazas FL, and Hurricane Sandy (2012) at Fire Island, NY. Hurricane Sandy was a Saffir-Simpson Category 2 hurricane that trans - Multimedia
- Publications
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Incorporating wave climate complexity into modeling lower shoreface morphology and transport
The lower shoreface, a transitional subaqueous region extending from the seaward limit of the surf zone to beyond the closure depth, serves as a sediment reservoir and pathway in sandy beach environments over annual to millennial time scales. Despite the important role this region plays in shoreline dynamics, the morphodynamics of the lower shoreface remain poorly quantified and understood. To betAuthorsMegan Gillen, Andrew D. Ashton, Jennifer L. Miselis, Daniel J. Ciarletta, Emily A. Wei, Christopher R. SherwoodModeling total water level and coastal change at Pea Island, North Carolina, USA
The DUring Nearshore Event eXperiment (DUNEX) was carried out on Pea Island, North Carolina, USA between September-October 2021. We use a coupled numerical model (Windsurf) to hindcast the evolution of the DUNEX transect and produce a time series of hourly water levels at the shoreline from the model output. In addition to assessing the ability of Windsurf to reproduce TWL, we use model output paiAuthorsMichael Christopher Itzkin, Margaret Louise Palmsten, Mark L. Buckley, Christopher R. Sherwood, Jenna A. Brown, Jin-Si R. Over, Peter A. TraykovskiContributions to uncertainty in runup forecasts
The U.S. Geological Survey (USGS) provides operational forecasts of total water levels (TWL) and coastal change. Uncertainties around forecast TWL are based on the temporal and spatial range of observed beach slopes near the forecast site. This paper investigates other sources of uncertainty that are not accounted for, focusing on four beaches where the USGS has deployed remote cameras, and on outAuthorsChristopher R. Sherwood, Alfredo Aretxabaleta, Peter A. Traykovski, Jin-Si R. Over, David S. Foster, Jennifer L. Miselis, Tim Nelson, Erdinc SogutProcesses controlling coastal erosion along Cape Cod Bay, MA
Cape Cod Bay, MA, is a semi-enclosed embayment in the northeastern United States, open on the north to the Gulf of Maine. The coastline experiences impacts typically from strong Nor’easter storms that occur in the late fall or winter months, with some sections of this coastline being affected more severely than others. We investigate the processes that cause spatial variability in storm impacts byAuthorsJohn C. Warner, Laura L. Brothers, Emily Himmelstoss, Christopher R. Sherwood, Alfredo Aretxabaleta, David S. Foster, Amy S. FarrisTemporal variability of runup and total water level on Cape Cod sandy beaches
In the present study, we evaluate the temporal variability in runup and total water level for sandy beaches along Cape Cod (Massachusetts, USA), and their impact on dune and beach erosion. We use a 43-year hindcast of waves and water levels and calculate runup and total water level based on the Stockdon formulation using previously extracted beach slopes. The dominant components of the runup are iAuthorsAlfredo Aretxabaleta, Christopher R. Sherwood, B.O. Blanton, Jin-Si R. Over, Peter A. Traykovski, Erdinc SogutSound-side inundation and seaward erosion of a barrier island during hurricane landfall
Barrier islands are especially vulnerable to hurricanes and other large storms, owing to their mobile composition, low elevations, and detachment from the mainland. Conceptual models of barrier-island evolution emphasize ocean-side processes that drive landward migration through overwash, inlet migration, and aeolian transport. In contrast, we found that the impact of Hurricane Dorian (2019) on NoAuthorsChristopher R. Sherwood, Andrew C. Ritchie, Jin-Si R. Over, Christine J. Kranenburg, Jonathan Warrick, Jenna A. Brown, Wayne Wright, Alfredo Aretxabaleta, Sara Zeigler, Phillipe Alan Wernette, Daniel D. Buscombe, Christie HegermillerCoastalImageLib: An open-source Python package for creating common coastal image products
CoastalImageLib is a Python library that produces common coastal image products intended for quantitative analysis of coastal environments. This library contains functions to georectify and merge multiple oblique camera views, produce statistical image products for a given set of images, and create subsampled pixel instruments for use in bathymetric inversion, surface current estimation, run-up caAuthorsMaile McCann, Dylan L. Anderson, Christopher R. Sherwood, Brittany Bruder, A. Spicer Bak, Katherine BrodieShoaling wave shape estimates from field observations and derived bedload sediment rates
The shoaling transformation from generally linear deep-water waves to asymmetric shallow-water waves modifies wave shapes and causes near-bed orbital velocities to become asymmetrical, contributing to net sediment transport. In this work, we used two methods to estimate the asymmetric wave shape from data at three sites. The first method converted wave measurements made at the surface to idealizedAuthorsTarandeep S. Kalra, Steven E. Suttles, Christopher R. Sherwood, John C. Warner, Alfredo Aretxabaleta, Gibson Robert Scott LeavittHuman-in-the-Loop segmentation of earth surface imagery
Segmentation, or the classification of pixels (grid cells) in imagery, is ubiquitously applied in the natural sciences. Manual methods are often prohibitively time-consuming, especially those images consisting of small objects and/or significant spatial heterogeneity of colors or textures. Labeling complicated regions of transition that in Earth surface imagery are represented by collections of miAuthorsDaniel D. Buscombe, Evan B. Goldstein, Christopher R. Sherwood, Cameron S Bodine, Jenna A. Brown, Jaycee Favela, Sharon Fitzpatrick, Christine J. Kranenburg, Jin-Si R. Over, Andrew C. Ritchie, Jonathan Warrick, Phillipe Alan WernetteModeling of barrier breaching during Hurricanes Sandy and Matthew
Physical processes driving barrier island change during storms are important to understand to mitigate coastal hazards and to evaluate conceptual models for barrier evolution. Spatial variations in barrier island topography, landcover characteristics, and nearshore and back-barrier hydrodynamics can yield complex morphological change that requires models of increasing resolution and physical complAuthorsChristie Hegermiller, John C. Warner, Maitane Olabarrieta, Christopher R. Sherwood, Tarandeep S. KalraModeling morphodynamics of coastal response to extreme events: What shape are we in?
This review focuses on recent advances in process-based numerical models of the impact of extreme storms on sandy coasts. Driven by larger-scale models of meteorology and hydrodynamics, these models simulate morphodynamics across the Sallenger storm-impact scale, including swash, collision, overwash, and inundation. Models are becoming both wider (as more processes are added) and deeper (as detailAuthorsChristopher R. Sherwood, Ap van Dongeren, James Doyle, Christie Hegermiller, T. J. Hsu, Tarandeep S. Kalra, Maitane Olabarrieta, Allison Penko, Yashar Rafati, Dano Roelvink, Marlies van der Lugt, Jay Veeramony, John C. WarnerProcessing coastal imagery with Agisoft Metashape Professional Edition, version 1.6—Structure from motion workflow documentation
IntroductionStructure from motion (SFM) has become an integral technique in coastal change assessment; the U.S. Geological Survey (USGS) used Agisoft Metashape Professional Edition photogrammetry software to develop a workflow that processes coastline aerial imagery collected in response to storms since Hurricane Florence in 2018. This report details step-by-step instructions to create three-dimen
AuthorsJin-Si R. Over, Andrew C. Ritchie, Christine J. Kranenburg, Jenna A. Brown, Daniel D. Buscombe, Tom Noble, Christopher R. Sherwood, Jonathan A. Warrick, Phillipe A. WernetteByEcosystems Mission Area, Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Maryland-Delaware-D.C. Water Science Center, Pacific Coastal and Marine Science Center, Southwest Biological Science Center, St. Petersburg Coastal and Marine Science Center, Woods Hole Coastal and Marine Science Center, Hurricane Florence, Hurricanes - Software
COAWST Modeling System v3.4
Coupled ocean atmosphere wave sediment transport modeling system - News