Extended Water Level Trends at Long‐Record Tide Gauges Via Moving Window Averaging and Implications for Future Coastal Flooding

Abstract

Global sea level rise (GSLR) is sensitive to increased climate change feedbacks and there is much uncertainty in accurately predicting changes in total water level and the associated impacts to coastal zones. The twentieth century has seen a rapid increase in GSLR over the last three millennia (Kopp et al., 2016), and many studies have suggested that sea-level rise is accelerating (e.g., Church & White, 2006Nerem & Fasullo, 2019), due in part to increased heating of the upper ocean (Domingues et al., 2008) and rapidly melting polar ice (Nicholls & Cazenave, 2010;Sallenger et al., 2012). Extended water level (EWL) is sum of monthly averaged mean sea level (MSL) and enhanced tidal range (ETR), with "enhanced tidal range" being a linear sum of the six largest astronomical tidal constituents and the six largest shallow-water overtides.