Publication
Global assessment of coastal storm hazards on Barrier islands
| Summary: | The vulnerability of barrier islands to coastal storm hazards is a growing challenge, exacerbated by climate change. Local high-resolution information on storm forcing and geomorphology has allowed the development of early warning systems to predict hazards and implement preparedness strategies. However, collecting high-resolution pre- and post-storm data can be costly, challenging and unfeasible at many coastal locations. The use of global low-resolution topo-bathymetry and wave reanalysis datasets presents an unprecedented opportunity to expand coastal hazard assessments, even if at the cost of introducing errors and uncertainties. Aiming to evaluate the response of wave-dominated barrier islands to extreme storms at a global scale, this study validated the latest global wave reanalyses and digital elevation models against high resolution data. The validation confirmed biases associated with the resolution of global datasets and their inability to resolve complex features of wave propagation and morphology at local scales. Underestimation of extreme wave conditions in coastal areas was observed, and calibration equations were developed to reduce this negative bias. For the topo-bathymetry of barrier islands, an underestimation of the dune crest was identified, and gaps at the land-ocean interface were filled by merging the topo-bathymetry datasets using an equilibrium profile. The best performing global datasets were selected for the first global assessment of erosion and flooding hazards of natural barrier islands. This was achieved simulating the impact of a coastal storm with 50-year return period wave heights using the XBeach process-based model. Based on the implementation of process-based indicators, the strong control that storm hydrodynamics exert on the erosional response was highlighted, allowing the identification of erosion and flooding hotspots that coincided with areas of extra-tropical and tropical cyclone impact. These findings highlight the global patterns of barrier island vulnerability and provide a framework for prioritizing risk mitigation efforts in the face of intensifying coastal hazards. |
|---|---|
| Main Authors: | Fanti, Valeria |
| Subject: | Barrier islands Coastal storm hazards Global models XBeach Process-based indicators |
| Year: | 2025 |
| Country: | Portugal |
| Document type: | doctoral thesis |
| Access type: | open access |
| Associated institution: | Universidade do Algarve |
| Language: | English |
| Origin: | Sapientia - Universidade do Algarve |
| Summary: | The vulnerability of barrier islands to coastal storm hazards is a growing challenge, exacerbated by climate change. Local high-resolution information on storm forcing and geomorphology has allowed the development of early warning systems to predict hazards and implement preparedness strategies. However, collecting high-resolution pre- and post-storm data can be costly, challenging and unfeasible at many coastal locations. The use of global low-resolution topo-bathymetry and wave reanalysis datasets presents an unprecedented opportunity to expand coastal hazard assessments, even if at the cost of introducing errors and uncertainties. Aiming to evaluate the response of wave-dominated barrier islands to extreme storms at a global scale, this study validated the latest global wave reanalyses and digital elevation models against high resolution data. The validation confirmed biases associated with the resolution of global datasets and their inability to resolve complex features of wave propagation and morphology at local scales. Underestimation of extreme wave conditions in coastal areas was observed, and calibration equations were developed to reduce this negative bias. For the topo-bathymetry of barrier islands, an underestimation of the dune crest was identified, and gaps at the land-ocean interface were filled by merging the topo-bathymetry datasets using an equilibrium profile. The best performing global datasets were selected for the first global assessment of erosion and flooding hazards of natural barrier islands. This was achieved simulating the impact of a coastal storm with 50-year return period wave heights using the XBeach process-based model. Based on the implementation of process-based indicators, the strong control that storm hydrodynamics exert on the erosional response was highlighted, allowing the identification of erosion and flooding hotspots that coincided with areas of extra-tropical and tropical cyclone impact. These findings highlight the global patterns of barrier island vulnerability and provide a framework for prioritizing risk mitigation efforts in the face of intensifying coastal hazards. |
|---|
Funded activities
Loading funded projects...