A Coupled wave-storm surge model for coastal vulnerability assessment for the Bahamas Archipelago
Abstract
The Bahamas archipelago in the Atlantic Ocean is highly vulnerable to increased storminess and response of climate change. The archipelago encounters regular strike of hurricanes due to its position along the major pathway of hurricanes originating from Caribbean and tropical Atlantic basin. In addition to frequent hurricane activity, low lying morphology and sea level rise (0.3 m during past two decades) has exposed the archipelago more vulnerable to the impact of storm surge and coastal inundation. Regardless of the history of past hurricane landfall on Bahamas archipelago, limited records and studies are found detailing the impact of storm tide, hurricane induced wave and their integrated effect on its fragile coastal zone. The archipelago borders narrow and steep continental shelf with curvatures which enhances the wave activity as well piling up of surge water farther inshore due to increased water level elevation. A fully coupled ADCIRC-SWAN model has been developed for the archipelago, focusing in detail the relief of the coastal zone, coastline curvature and the steep and narrow continental shelf. The study simulates Hurricane Joaquin which made multiple landfall over the Bahamas archipelago in 2015, for the assessment of coastal vulnerability from nonlinear interaction of wave and storm tide. The looped trajectory of Joaquin with its intensification and stalling over the archipelago resulted in the generation of a bimodal storm surge and wave height profiles with a time lag. Interestingly, the leeside of the archipelago is found to be highly susceptible from hurricane induced waves (Hsig ≈ 8-9 m); however the bay shaped coastline and the orientation of the islands facilitate buildup of higher storm tide (≈1-2 m) over the shadow zone of the islands. The study performs several synthetic experiments by shifting the Joaquin landfall location to quantify the impacts with respect to the coastal geomorphology around the Bahamas archipelago. The study also maps the vulnerability of the island chain for varying hurricane intensity.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS51C1264J
- Keywords:
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- 4546 Nearshore processes;
- OCEANOGRAPHY: PHYSICALDE: 4558 Sediment transport;
- OCEANOGRAPHY: PHYSICALDE: 4562 Topographic/bathymetric interactions;
- OCEANOGRAPHY: PHYSICALDE: 4564 Tsunamis and storm surges;
- OCEANOGRAPHY: PHYSICAL