Wind impact on sea level variability along the US Atlantic and Gulf coasts: implications to coastal flooding hazard

Abstract Sea level variability is driven by a combination of processes, including gravitational forces, ocean currents, and winds. This study investigates the contributions of offshore and local wind direction and magnitude to non-tidal residual (NTR) corrected for global mean sea level rise and local vertical land movements along the US Atlantic and Gulf coasts, and their implications for coastal flooding. Daily mean sea level and local wind data from eighteen National Oceanic and Atmospheric Administration (NOAA) tide gauges were analysed alongside offshore wind data from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP-NCAR) reanalysis. Wind velocity fields were decomposed into 12 directional components (0° to 165°) relative to the coastline to evaluate the directional influence of wind on sea level variability. Annual correlation analyses were conducted to analyse the relationship between wind forcing and sea level variability at each station. Our results indicate that local winds have a negligible impact on sea level variability, regardless of their direction. In contrast, offshore winds account for 30–50% of the variability at ten stations, 15–30% at four stations, and less than 15% at the remaining four stations. Each station exhibited a dominant range of wind directions. Additionally, we identified a regional wind pattern that is temporally correlated with the occurrences of extreme high and low NTR events. These findings highlight the significant influence of offshore winds on coastal sea levels, emphasizing the need for coastal flood mitigation strategies to incorporate offshore wind patterns into risk assessments.