Impacts of Hurricane Winds and Precipitation on Hydrodynamics in a Back‐Barrier Estuary. Issue 12 (2nd December 2020)

• Record Type: Journal Article
• Authors: Rey, Alexander J. M.; Corbett, D. Reide; Mulligan, Ryan P.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 12(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-02
• Subjects: coastal oceanography -- Delft3D -- numerical modeling -- storm surge -- surface waves -- tropical cyclones; Oceanography -- Periodicals; 551.4605
• DOI: 10.1029/2020JC016483
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: During extreme storms, both wind‐driven changes in water levels and intense precipitation can contribute to flooding. Particularly on low‐lying coastal plains, storm‐driven flooding can cover large areas, resulting in major damage. To investigate the roles of rainfall and storm surge on coastal flooding, a coupled flow‐wave model (Delft3D‐SWAN) that includes precipitation is used to simulate two major storm events. The modeling system is applied over a domain covering coastal North Carolina, USA, including the large Albemarle‐Pamlico estuarine system, and a long and narrow back‐barrier estuary (Currituck Sound [CS]) that experiences major water level variations is investigated in detail. A high‐resolution (50 m) grid with eight vertical layers is used to simulate the conditions during Tropical Storm Hermine and Hurricane Matthew in 2016. Hindcasts (winds, pressure, and precipitation) from eight different atmospheric models are used as atmospheric input conditions, and the results are compared with detailed observations of surface waves, currents, and water levels from sensors mounted on five monitoring platforms in CS. Results show that major differences exist between wind fields producing variations coastal conditions. Precipitation directly on the water surface had a large effect on water levels and produced a larger inundated area. These results help to understand the important contributions of each physical process (precipitation, wind‐driven surge, and waves) to circulation and water levels, and provide guidance on the impact of atmospheric forcing conditions on back‐barrier environments during hurricanes. Plain Language Summary: Winds and heavy rain can result in coastal flooding during extreme storms, such as hurricanes. This is a major hazard in coastal areas, where flooding from storms can cover large areas and produce substantial damage. To help understand the forces that contribute to this hazard, a model is applied to simulate the waves, water levels, and currents in Currituck Sound (CS), part of the larger Albemarle‐Pamlico estuarine system in coastal North Carolina, USA. Two major storms are simulated, Tropical Storm Hermine and Hurricane Matthew in September and October 2016. Observations were collected from five monitoring platforms in CS, and the measurements indicate that large changes in water levels occurred during both storms. Winds, pressure, and precipitation are used as model inputs, and the simulation results are compared with observations of surface waves, currents, and water levels. The results help to understand the roles of precipitation, wind, and waves on the motion of water in back‐barrier estuaries and coastal flooding during tropical storms. Key Points: Surface waves and coastal hydrodynamic were simulated in a long and narrow estuary during two tropical storms After comparing atmospheric inputs, model results were in general agreement with observations from five monitoring platforms using Rapid Refresh winds Results indicate that both wind‐driven storm surge and precipitation directly on the water surface contribute to flooding