The USGS is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data. The U.S.
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.
Google Scholar
Science and Products
Estuarine Processes, Hazards, and Ecosystems
Coastal Model Applications and Field Measurements- Field Measurements and Model Applications
Estuarine Processes Model Development
Lifespan of marsh units in Eastern Shore of Virginia salt marshes
Lifespan of marsh units in Connecticut salt marshes
Lifespan of marsh units in New York salt marshes
Geospatial characterization of salt marshes in Maine
Geospatial characterization of salt marshes in Connecticut (ver. 2.0, April 2024
Inventory of Managed Coastal Wetlands in Delaware Bay and Delaware's Inland Bays
Lifespan of Massachusetts salt marsh units
Geospatial characterization of salt marshes on the Eastern Shore of Virginia
Lifespan of Chesapeake Bay salt marsh units
Geospatial characterization of salt marshes in Chesapeake Bay
Lifespan of marsh units in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
An Unvegetated to Vegetated Ratio (UVVR) for coastal wetlands of the Conterminous United States (2014-2018)
![Screenshot shows 5 linked topics on the Coastal Wetland Synthesis Applications geonarrative webpage.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/US%20Coastal%20Wetland%20Syn.png?itok=8ajMrAC3)
The USGS is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data. The U.S.
![USGS logo, U.S. Coastal Wetland Geospatial Collection title and intro text on left. Links to interactive maps on the right](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/Collection%20homepage.png?itok=JT15W6Lu)
The collection provides a motivation for the USGS coastal wetland research and individual web apps where users can browse each CONUS-wide data separately (relative tidal elevation, unvegetated-vegetated ratio, and aboveground biomass). It also provides a Collection viewer, where users can browse the CONUS-wide collection on the same map.
The collection provides a motivation for the USGS coastal wetland research and individual web apps where users can browse each CONUS-wide data separately (relative tidal elevation, unvegetated-vegetated ratio, and aboveground biomass). It also provides a Collection viewer, where users can browse the CONUS-wide collection on the same map.
Users can navigate the collection by clicking on the tiles on the cover page or the tabbed menu. With the Collection viewer, users can use a swipe tool to compare layers and click to see the values for each pixel. Users can also add other data to the viewer and bookmark any locations of interest.
Users can navigate the collection by clicking on the tiles on the cover page or the tabbed menu. With the Collection viewer, users can use a swipe tool to compare layers and click to see the values for each pixel. Users can also add other data to the viewer and bookmark any locations of interest.
Pre- and post-Hurricane Dorian aerial imagery showing extreme sediment transport, overwash and breaches along the barrier islands of the North Carolina coast.
Pre- and post-Hurricane Dorian aerial imagery showing extreme sediment transport, overwash and breaches along the barrier islands of the North Carolina coast.
Example from development of an atmospheric model for Hurricane Florence. The images display a comparison between the control case, WRF-ROMS-SWAN modeling system and the multi-sensor (radar and rain) precipitation observations during the calibration of the model.
Example from development of an atmospheric model for Hurricane Florence. The images display a comparison between the control case, WRF-ROMS-SWAN modeling system and the multi-sensor (radar and rain) precipitation observations during the calibration of the model.
Example from development of an atmospheric model for Hurricane Florence. The animation shows the changing atmospheric pressure and wind fields during the storm as simulated by the model. Arrows display wind direction, colors indicate atmospheric pressure ranging from 97,500 pascals (red) to 102,460 pascals (blue).
Example from development of an atmospheric model for Hurricane Florence. The animation shows the changing atmospheric pressure and wind fields during the storm as simulated by the model. Arrows display wind direction, colors indicate atmospheric pressure ranging from 97,500 pascals (red) to 102,460 pascals (blue).
Hurricane Florence numerical modeling: Cape Fear River basin boundaries, topography, river streams and measurement locations. USGS streamflow and rain gages, and Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) gages are shown. Stream order increases going from branches to the main channel indicating merging surface water flow.
Hurricane Florence numerical modeling: Cape Fear River basin boundaries, topography, river streams and measurement locations. USGS streamflow and rain gages, and Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) gages are shown. Stream order increases going from branches to the main channel indicating merging surface water flow.
Hurricane Florence numerical modeling: The Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro) is used to simulate surface and subsurface flows on land.
Hurricane Florence numerical modeling: The Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro) is used to simulate surface and subsurface flows on land.
Hurricane Sandy (2012) modeling: Modeling can reveal the contributions from underlying processes individually. These images show contribution from offshore surge (change in water level) and offshore waves to maximum water levels (in meters) within a bay during a coastal storm.
Hurricane Sandy (2012) modeling: Modeling can reveal the contributions from underlying processes individually. These images show contribution from offshore surge (change in water level) and offshore waves to maximum water levels (in meters) within a bay during a coastal storm.
Photo of a boardwalk over a saltmarsh creek showing people.
Photo of a boardwalk over a saltmarsh creek showing people.
Photo showing floating cages for oyster farming in a marsh creek exposed at low tide.
Photo showing floating cages for oyster farming in a marsh creek exposed at low tide.
Photo showing different species of salt tolerant plants near a saltmarsh.
Photo showing different species of salt tolerant plants near a saltmarsh.
Photo of a saltmarsh platform showing vegetation on on top of the banks of a tidal creek. It shows the general setting of a saltmarshes that experience wet and dry periods with the tides within a day.
Photo of a saltmarsh platform showing vegetation on on top of the banks of a tidal creek. It shows the general setting of a saltmarshes that experience wet and dry periods with the tides within a day.
Hurricane Florence (2018) modeling: The coupled model captures the stages of compound flooding in the Cape Fear River Estuary starting with swell from offshore, followed by storm surge from the ocean side, later transitioning to flooding from land side with the storm water runoff because of rain.
Hurricane Florence (2018) modeling: The coupled model captures the stages of compound flooding in the Cape Fear River Estuary starting with swell from offshore, followed by storm surge from the ocean side, later transitioning to flooding from land side with the storm water runoff because of rain.
Edwin B. Forsythe National Wildlife Refuge, New Jersey Study SIte
Edwin B. Forsythe National Wildlife Refuge, New Jersey Study SIte
![Browse graphic of Edwin B Forsythe National Wildlife Refuge study area](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/EBF_NWR.png?itok=tkqSTemB)
Browse graphic of Edwin B Forsythe National Wildlife Refuge study area
Browse graphic of Edwin B Forsythe National Wildlife Refuge study area
Modeled coastal-ocean pathways of land-sourced contaminants in the aftermath of Hurricane Florence
Using geospatial analysis to guide marsh restoration in Chesapeake Bay and beyond
Horizontal integrity a prerequisite for vertical stability: Comparison of elevation change and the unvegetated-vegetated marsh ratio across southeastern USA coastal wetlands
Development and application of Landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States
Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model
Quantifying slopes as a driver of forest to marsh conversion using geospatial techniques: Application to Chesapeake Bay coastal-plain, USA
A geospatially resolved wetland vulnerability index: Synthesis of physical drivers
Are elevation and open-water conversion of salt marshes connected?
Understanding tidal marsh trajectories: Evaluation of multiple indicators of marsh persistence
Hydrodynamic and morphologic response of a back-barrier estuary to an extratropical storm
Identifying salt marsh shorelines from remotely sensed elevation data and imagery
Spatial distribution of water level impact to back-barrier bays
U.S. Coastal Wetland Synthesis Applications Geonarrative
The U.S. Geological Survey (USGS) is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data.
U.S. Coastal Wetland Geospatial Datasets Collection and Coastal Wetlands Geonarrative
Scientists from across USGS have created the first CONUS-wide collection of key tidal wetland metrics. These metrics provide data on habitat quality, geomorphic vulnerability, and carbon stock that are necessary to understand the current and future ecosystem services provided by coastal wetlands.
Hurricane Florence Numerical Modeling
The U.S. Geological Survey (USGS) has partnered with North Carolina State University (NCSU), Louisiana State University (LSU) and University Corporation for Atmospheric Research (UCAR) to investigate hurricane-induced compound flooding and sediment dispersal using coupled hydrology and ocean models.
National UVVR Map
This map shows the unvegetated and vegetated area of coastal wetlands and adjacent land (inland and shorelines) for the Conterminous United States computed from 2014-2018 Landsat imagery at ~30 meter horizontal resolution.
Sea Level Change
An Interactive Guide to Global and Regional Sea Level Rise Scenarios for the United States
Science and Products
Estuarine Processes, Hazards, and Ecosystems
Coastal Model Applications and Field Measurements- Field Measurements and Model Applications
Estuarine Processes Model Development
Lifespan of marsh units in Eastern Shore of Virginia salt marshes
Lifespan of marsh units in Connecticut salt marshes
Lifespan of marsh units in New York salt marshes
Geospatial characterization of salt marshes in Maine
Geospatial characterization of salt marshes in Connecticut (ver. 2.0, April 2024
Inventory of Managed Coastal Wetlands in Delaware Bay and Delaware's Inland Bays
Lifespan of Massachusetts salt marsh units
Geospatial characterization of salt marshes on the Eastern Shore of Virginia
Lifespan of Chesapeake Bay salt marsh units
Geospatial characterization of salt marshes in Chesapeake Bay
Lifespan of marsh units in Assateague Island National Seashore and Chincoteague Bay, Maryland and Virginia
An Unvegetated to Vegetated Ratio (UVVR) for coastal wetlands of the Conterminous United States (2014-2018)
![Screenshot shows 5 linked topics on the Coastal Wetland Synthesis Applications geonarrative webpage.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/US%20Coastal%20Wetland%20Syn.png?itok=8ajMrAC3)
The USGS is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data. The U.S.
The USGS is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data. The U.S.
![USGS logo, U.S. Coastal Wetland Geospatial Collection title and intro text on left. Links to interactive maps on the right](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/Collection%20homepage.png?itok=JT15W6Lu)
The collection provides a motivation for the USGS coastal wetland research and individual web apps where users can browse each CONUS-wide data separately (relative tidal elevation, unvegetated-vegetated ratio, and aboveground biomass). It also provides a Collection viewer, where users can browse the CONUS-wide collection on the same map.
The collection provides a motivation for the USGS coastal wetland research and individual web apps where users can browse each CONUS-wide data separately (relative tidal elevation, unvegetated-vegetated ratio, and aboveground biomass). It also provides a Collection viewer, where users can browse the CONUS-wide collection on the same map.
Users can navigate the collection by clicking on the tiles on the cover page or the tabbed menu. With the Collection viewer, users can use a swipe tool to compare layers and click to see the values for each pixel. Users can also add other data to the viewer and bookmark any locations of interest.
Users can navigate the collection by clicking on the tiles on the cover page or the tabbed menu. With the Collection viewer, users can use a swipe tool to compare layers and click to see the values for each pixel. Users can also add other data to the viewer and bookmark any locations of interest.
Pre- and post-Hurricane Dorian aerial imagery showing extreme sediment transport, overwash and breaches along the barrier islands of the North Carolina coast.
Pre- and post-Hurricane Dorian aerial imagery showing extreme sediment transport, overwash and breaches along the barrier islands of the North Carolina coast.
Example from development of an atmospheric model for Hurricane Florence. The images display a comparison between the control case, WRF-ROMS-SWAN modeling system and the multi-sensor (radar and rain) precipitation observations during the calibration of the model.
Example from development of an atmospheric model for Hurricane Florence. The images display a comparison between the control case, WRF-ROMS-SWAN modeling system and the multi-sensor (radar and rain) precipitation observations during the calibration of the model.
Example from development of an atmospheric model for Hurricane Florence. The animation shows the changing atmospheric pressure and wind fields during the storm as simulated by the model. Arrows display wind direction, colors indicate atmospheric pressure ranging from 97,500 pascals (red) to 102,460 pascals (blue).
Example from development of an atmospheric model for Hurricane Florence. The animation shows the changing atmospheric pressure and wind fields during the storm as simulated by the model. Arrows display wind direction, colors indicate atmospheric pressure ranging from 97,500 pascals (red) to 102,460 pascals (blue).
Hurricane Florence numerical modeling: Cape Fear River basin boundaries, topography, river streams and measurement locations. USGS streamflow and rain gages, and Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) gages are shown. Stream order increases going from branches to the main channel indicating merging surface water flow.
Hurricane Florence numerical modeling: Cape Fear River basin boundaries, topography, river streams and measurement locations. USGS streamflow and rain gages, and Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) gages are shown. Stream order increases going from branches to the main channel indicating merging surface water flow.
Hurricane Florence numerical modeling: The Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro) is used to simulate surface and subsurface flows on land.
Hurricane Florence numerical modeling: The Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro) is used to simulate surface and subsurface flows on land.
Hurricane Sandy (2012) modeling: Modeling can reveal the contributions from underlying processes individually. These images show contribution from offshore surge (change in water level) and offshore waves to maximum water levels (in meters) within a bay during a coastal storm.
Hurricane Sandy (2012) modeling: Modeling can reveal the contributions from underlying processes individually. These images show contribution from offshore surge (change in water level) and offshore waves to maximum water levels (in meters) within a bay during a coastal storm.
Photo of a boardwalk over a saltmarsh creek showing people.
Photo of a boardwalk over a saltmarsh creek showing people.
Photo showing floating cages for oyster farming in a marsh creek exposed at low tide.
Photo showing floating cages for oyster farming in a marsh creek exposed at low tide.
Photo showing different species of salt tolerant plants near a saltmarsh.
Photo showing different species of salt tolerant plants near a saltmarsh.
Photo of a saltmarsh platform showing vegetation on on top of the banks of a tidal creek. It shows the general setting of a saltmarshes that experience wet and dry periods with the tides within a day.
Photo of a saltmarsh platform showing vegetation on on top of the banks of a tidal creek. It shows the general setting of a saltmarshes that experience wet and dry periods with the tides within a day.
Hurricane Florence (2018) modeling: The coupled model captures the stages of compound flooding in the Cape Fear River Estuary starting with swell from offshore, followed by storm surge from the ocean side, later transitioning to flooding from land side with the storm water runoff because of rain.
Hurricane Florence (2018) modeling: The coupled model captures the stages of compound flooding in the Cape Fear River Estuary starting with swell from offshore, followed by storm surge from the ocean side, later transitioning to flooding from land side with the storm water runoff because of rain.
Edwin B. Forsythe National Wildlife Refuge, New Jersey Study SIte
Edwin B. Forsythe National Wildlife Refuge, New Jersey Study SIte
![Browse graphic of Edwin B Forsythe National Wildlife Refuge study area](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/EBF_NWR.png?itok=tkqSTemB)
Browse graphic of Edwin B Forsythe National Wildlife Refuge study area
Browse graphic of Edwin B Forsythe National Wildlife Refuge study area
Modeled coastal-ocean pathways of land-sourced contaminants in the aftermath of Hurricane Florence
Using geospatial analysis to guide marsh restoration in Chesapeake Bay and beyond
Horizontal integrity a prerequisite for vertical stability: Comparison of elevation change and the unvegetated-vegetated marsh ratio across southeastern USA coastal wetlands
Development and application of Landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States
Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model
Quantifying slopes as a driver of forest to marsh conversion using geospatial techniques: Application to Chesapeake Bay coastal-plain, USA
A geospatially resolved wetland vulnerability index: Synthesis of physical drivers
Are elevation and open-water conversion of salt marshes connected?
Understanding tidal marsh trajectories: Evaluation of multiple indicators of marsh persistence
Hydrodynamic and morphologic response of a back-barrier estuary to an extratropical storm
Identifying salt marsh shorelines from remotely sensed elevation data and imagery
Spatial distribution of water level impact to back-barrier bays
U.S. Coastal Wetland Synthesis Applications Geonarrative
The U.S. Geological Survey (USGS) is assessing the physical condition of coastal wetlands and their response to external forces, using field observations and remote-sensing data.
U.S. Coastal Wetland Geospatial Datasets Collection and Coastal Wetlands Geonarrative
Scientists from across USGS have created the first CONUS-wide collection of key tidal wetland metrics. These metrics provide data on habitat quality, geomorphic vulnerability, and carbon stock that are necessary to understand the current and future ecosystem services provided by coastal wetlands.
Hurricane Florence Numerical Modeling
The U.S. Geological Survey (USGS) has partnered with North Carolina State University (NCSU), Louisiana State University (LSU) and University Corporation for Atmospheric Research (UCAR) to investigate hurricane-induced compound flooding and sediment dispersal using coupled hydrology and ocean models.
National UVVR Map
This map shows the unvegetated and vegetated area of coastal wetlands and adjacent land (inland and shorelines) for the Conterminous United States computed from 2014-2018 Landsat imagery at ~30 meter horizontal resolution.
Sea Level Change
An Interactive Guide to Global and Regional Sea Level Rise Scenarios for the United States