Impacts of Ocean Warming, Sea Level Rise, and Coastline Management on Storm Surge in a Semienclosed Bay

Regional atmosphere and ocean models are used to investigate how sea level rise, ocean warming, and coastline management affect storm surge in the semienclosed Chesapeake Bay. Using Hurricane Isabel (2003) as a case study, the storm is placed under the climatic conditions projected for 2050 and 2100. Higher sea surface temperature increases the latent heat release from the ocean, resulting in large increases in storm intensity and maximum sustained wind speeds. The storm surge height, defined as the difference between storm tide and astronomical tide, is amplified in the future climate and amounts to ~30% of the relative sea level rise. Hardening shorelines further increases the storm surge height in the middle and upper parts of the Bay by up to 0.5 m. Sea level rise has a modest impact on the storm surge height: decreasing it by 0.1-0.2 m if the low-lying areas are allowed to be flooded but increases it by 0.1-0.3 m if hypothetic walls are placed at the current coastline. Ocean warming is the main driver of storm surge amplification in the future climate. Energy budget analysis shows that allowing flooding over low-lying areas leads to a significant energy loss and reduces the storm surge height in the estuary.