Coastal Sea Level Variability and the Implications for Atmospheric Storms to Increase Societal Vulnerability: Do We Need for a Coastal Inundation and Flood Index?

Coastal cities and communities in the Atlantic and Pacific Ocean Basins are defined by high population densities at great potential risk of coastal inundation. In the United States, significant portions of the economy, commercial activity, and ecosystem assets are located at or within 100 km of the coast, making them vulnerable to sea level variability, especially relative rises. Moreover, future atmospheric storms may cause considerably more damage versus that of the past, given an elevated mean sea level (MSL). Although global mean sea level and sea level rise (SLR) are fundamental considerations, regional mean sea level (RSL) variability along the boundaries of ocean basins are critical, particularly if the amplitudes of seasonal to annual to inter-annual variability is high. Society must anticipate future storm induced impacts enhanced by changing RSL. In this study we evaluate local variability in coastal Pacific Ocean Basin sea level time series at Honolulu Hawaii, San Diego and San Francisco California, and, North Atlantic Ocean Basin sea level time series at Sewell's Point Virginia, Atlantic City New Jersey, Boston Massachusetts, Charleston South Carolina, Galveston Texas and Pensacola Florida. The time series extend variously back to the mid to late 19th and early 20th centuries through the present. Based on several hot spots of sea level rise and specific regional trends, future atmospheric storm induced coastal ocean inundation and flooding is investigated. The implications for coastal communities are presented and the case of a societal need for a quality coastal flood risk index on a fine spatial scale is put forward.