Abstract

Over the past 30 years, satellite-based radar altimetry has revolutionized the measurement of sea level changes on global and regional scales. However, conventional altimeters, designed primarily for open-ocean observations, face significant challenges in coastal zones, particularly within 20 km of the shoreline, where radar signals are contaminated by land reflections. This limitation has impeded precise monitoring of coastal sea level variations, which are crucial for understanding local coastal processes and assessing risks to coastal communities. The Surface Water and Ocean Topography (SWOT) mission, developed by NASA and CNES, represents a breakthrough in coastal sea level observation. Equipped with the innovative Ka-band Radar Interferometer (KaRIn), SWOT offers unprecedented high-resolution (2 km) sea surface height (SSH) measurements across a two-dimensional swath, enabling detailed analysis of coastal sea level dynamics. Furthermore, SWOT's high-resolution SSH mapping enables the detection of extreme coastal sea level events, such as storm surges, providing a novel tool for monitoring and characterizing the processes involved in these phenomena. This project evaluates SWOT's performance in coastal regions by comparing it against tide gauges, ERA5 reanalysis weather model and SCHISM ocean circulation model. This study has the potential to significantly advance our understanding of coastal processes and improve monitoring efforts for extreme events, with a focus on its capacity to detect storm surges, driven by strong winds and low atmospheric pressure during intense weather events like tropical cyclones and extratropical storms which cause abrupt and significant rises in sea level along coastlines.