Zafer Defne, PhD
My research finds its form in providing answers to questions related to coasts and ocean, based on my knowledge of physical oceanography and experience in data sciences.
Dr. Zafer Defne received his PhD in Coastal and Ocean Engineering from Georgia Institute of Technology, with a minor in Information Technology Applications in Oceanography. His expertise includes computational fluid dynamics and data analysis. His work on numerical modeling of coastal ocean has been used to assess storm surge, residual circulation, sediment transport and water quality, as well as marine renewable energy. His recent research is on assessment of the physical state of coastal wetlands using geospatial data.
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Science and Products
Filter Total Items: 55
Climatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico Climatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico
This U.S. Geological Survey data release provides data on spatial variations in climatological wave parameters (significant wave height, peak wave period, and wave power) for coastal areas along the United States East Coast and Gulf of Mexico. Significant wave height is the average wave height, from crest to trough, of the highest one-third of the waves in a specific time period. Peak...
Tidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay Tidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay
This U.S. Geological Survey data release provides data on spatial variations in tidal datums, tidal range, and nuisance flooding in Chesapeake Bay and Delaware Bay. Tidal datums are standard elevations that are defined based on average tidal water levels. Datums are used as references to measure local water levels and to delineate regions in coastal environments. Nuisance flooding refers...
COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics
The COAWST (Coupled Ocean-Atmosphere-Wave-Sediment Transport) modeling framework was extended to add two key processes that affect marshes, erosion due to lateral wave thrust (LWT) and vertical accretion due to biomass productivity. The testing of the combined effects of integrating these two processes was done by modeling marsh complexes within Forsythe National Wildlife Refuge and the...
Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Unvegetated to vegetated marsh ratio (UVVR) in the Assateague Island National Seashore and Chincoteague Bay is computed based on conceptual marsh units defined by Defne and Ganju (2018). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery. Through scientific efforts initiated with the Hurricane Sandy Science...
Geospatial Characterization of Salt Marshes for Massachusetts Geospatial Characterization of Salt Marshes for Massachusetts
This data release contains coastal wetland synthesis products for Massachusetts. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and tidal range are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health. The U.S. Geological Survey has been...
Wave thrust values at point locations along the shorelines of Massachusetts and Rhode Island Wave thrust values at point locations along the shorelines of Massachusetts and Rhode Island
This product provides spatial variations in wave thrust along shorelines in Massachusetts and Rhode Island. Natural features of relevance along the State coast are salt marshes. In recent times, marshes have been eroding primarily through lateral erosion. Wave thrust represents a metric of wave attack acting on marsh edges. The wave thrust is calculated as the vertical integral of the...
Filter Total Items: 26
Physical response of a back-barrier estuary to a post-tropical cyclone Physical response of a back-barrier estuary to a post-tropical cyclone
This paper presents a modeling investigation of the hydrodynamic and sediment transport response of Chincoteague Bay (VA/MD, USA) to Hurricane Sandy using the Coupled Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) modeling system. Several simulation scenarios with different combinations of remote and local forces were conducted to identify the dominant physical processes. While 80% of...
Authors
Alexis Beudin, Neil Kamal Ganju, Zafer Defne, Alfredo Aretxabaleta
Hydrokinetic tidal energy resource assessments using numerical models Hydrokinetic tidal energy resource assessments using numerical models
Hyrdokinetic tidal energy is the conversion of tidal current kinetic energy to another more useful form, frequently electricity. As with any other form of renewable energy, resource assessments are essential for the tidal energy project planning and design process. While tidal currents have significant spatial and temporal variability, the predictability of tidal flows makes...
Authors
Kevin Haas, Zafer Defne, Xiufeng Yang, Brittany Bruder
Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes
Salt marshes are valued for their ecosystem services, and their vulnerability is typically assessed through biotic and abiotic measurements at individual points on the landscape. However, lateral erosion can lead to rapid marsh loss as marshes build vertically. Marsh sediment budgets represent a spatially integrated measure of competing constructive and destructive forces: a sediment...
Authors
Neil K. Ganju, Zafer Defne, Matthew L. Kirwan, Sergio Fagherazzi, Andrea D’Alpaos, Luca Carniello
Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012–13 Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012–13
Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of...
Authors
Kristin M. Romanok, Zoltan Szabo, Timothy J. Reilly, Zafer Defne, Neil K. Ganju
Estimating time-dependent connectivity in marine systems Estimating time-dependent connectivity in marine systems
Hydrodynamic connectivity describes the sources and destinations of water parcels within a domain over a given time. When combined with biological models, it can be a powerful concept to explain the patterns of constituent dispersal within marine ecosystems. However, providing connectivity metrics for a given domain is a three-dimensional problem: two dimensions in space to define the...
Authors
Zafer Defne, Neil K. Ganju, Alfredo Aretxabaleta
Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity
Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island...
Authors
Jennifer L. Miselis, Brian D. Andrews, Robert S. Nicholson, Zafer Defne, Neil K. Ganju, Anthony S. Navoy
Science and Products
Filter Total Items: 55
Climatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico Climatological Wave Height, Wave Period and Wave Power along Coastal Areas of the East Coast of the United States and Gulf of Mexico
This U.S. Geological Survey data release provides data on spatial variations in climatological wave parameters (significant wave height, peak wave period, and wave power) for coastal areas along the United States East Coast and Gulf of Mexico. Significant wave height is the average wave height, from crest to trough, of the highest one-third of the waves in a specific time period. Peak...
Tidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay Tidal Datums, Tidal Range, and Nuisance Flooding Levels for Chesapeake Bay and Delaware Bay
This U.S. Geological Survey data release provides data on spatial variations in tidal datums, tidal range, and nuisance flooding in Chesapeake Bay and Delaware Bay. Tidal datums are standard elevations that are defined based on average tidal water levels. Datums are used as references to measure local water levels and to delineate regions in coastal environments. Nuisance flooding refers...
COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics COAWST model of Barnegat Bay creeks to demonstrate marsh dynamics
The COAWST (Coupled Ocean-Atmosphere-Wave-Sediment Transport) modeling framework was extended to add two key processes that affect marshes, erosion due to lateral wave thrust (LWT) and vertical accretion due to biomass productivity. The testing of the combined effects of integrating these two processes was done by modeling marsh complexes within Forsythe National Wildlife Refuge and the...
Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia Unvegetated to vegetated marsh ratio in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
Unvegetated to vegetated marsh ratio (UVVR) in the Assateague Island National Seashore and Chincoteague Bay is computed based on conceptual marsh units defined by Defne and Ganju (2018). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery. Through scientific efforts initiated with the Hurricane Sandy Science...
Geospatial Characterization of Salt Marshes for Massachusetts Geospatial Characterization of Salt Marshes for Massachusetts
This data release contains coastal wetland synthesis products for Massachusetts. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and tidal range are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health. The U.S. Geological Survey has been...
Wave thrust values at point locations along the shorelines of Massachusetts and Rhode Island Wave thrust values at point locations along the shorelines of Massachusetts and Rhode Island
This product provides spatial variations in wave thrust along shorelines in Massachusetts and Rhode Island. Natural features of relevance along the State coast are salt marshes. In recent times, marshes have been eroding primarily through lateral erosion. Wave thrust represents a metric of wave attack acting on marsh edges. The wave thrust is calculated as the vertical integral of the...
Filter Total Items: 26
Physical response of a back-barrier estuary to a post-tropical cyclone Physical response of a back-barrier estuary to a post-tropical cyclone
This paper presents a modeling investigation of the hydrodynamic and sediment transport response of Chincoteague Bay (VA/MD, USA) to Hurricane Sandy using the Coupled Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) modeling system. Several simulation scenarios with different combinations of remote and local forces were conducted to identify the dominant physical processes. While 80% of...
Authors
Alexis Beudin, Neil Kamal Ganju, Zafer Defne, Alfredo Aretxabaleta
Hydrokinetic tidal energy resource assessments using numerical models Hydrokinetic tidal energy resource assessments using numerical models
Hyrdokinetic tidal energy is the conversion of tidal current kinetic energy to another more useful form, frequently electricity. As with any other form of renewable energy, resource assessments are essential for the tidal energy project planning and design process. While tidal currents have significant spatial and temporal variability, the predictability of tidal flows makes...
Authors
Kevin Haas, Zafer Defne, Xiufeng Yang, Brittany Bruder
Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes
Salt marshes are valued for their ecosystem services, and their vulnerability is typically assessed through biotic and abiotic measurements at individual points on the landscape. However, lateral erosion can lead to rapid marsh loss as marshes build vertically. Marsh sediment budgets represent a spatially integrated measure of competing constructive and destructive forces: a sediment...
Authors
Neil K. Ganju, Zafer Defne, Matthew L. Kirwan, Sergio Fagherazzi, Andrea D’Alpaos, Luca Carniello
Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012–13 Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012–13
Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of...
Authors
Kristin M. Romanok, Zoltan Szabo, Timothy J. Reilly, Zafer Defne, Neil K. Ganju
Estimating time-dependent connectivity in marine systems Estimating time-dependent connectivity in marine systems
Hydrodynamic connectivity describes the sources and destinations of water parcels within a domain over a given time. When combined with biological models, it can be a powerful concept to explain the patterns of constituent dispersal within marine ecosystems. However, providing connectivity metrics for a given domain is a three-dimensional problem: two dimensions in space to define the...
Authors
Zafer Defne, Neil K. Ganju, Alfredo Aretxabaleta
Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity
Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island...
Authors
Jennifer L. Miselis, Brian D. Andrews, Robert S. Nicholson, Zafer Defne, Neil K. Ganju, Anthony S. Navoy