Quantifying the drivers of sea level changes along Singapore’s coastline: the role of tides, non-tidal residuals, and wave dynamics

<p dir="ltr">Low-lying coastal cities such as Singapore are increasingly vulnerable to climate change and flooding, particularly due to sea level rise and variability. Storm tide, the elevated sea level from a combination of storm and astronomical tide, is influenced by global and local factors. Understanding their interaction is crucial for effective coastal management and enhancing the resilience of Singapore’s coastal regions. The total water level at the coastline is determined by two components: still water level and wave runup. The still water level is affected by astronomical tides, non-tidal residuals, and vertical land motion, while wave runup adds dynamic contributions that shape flooding and erosion risks. Accurately estimating storm tide requires considering a wide range of temporal and spatial drivers. By integrating tide gauge and satellite altimetry data with numerical models, this study examines the main drivers of sea level changes along Singapore’s coastline, focusing on tidal range, sea level rise, sea level anomalies, and wave runup at Tanjong Pagar station. Outputs from Delft3D-FLOW and -WAVE modules estimate wave runup for varying slopes. For 2020, the maximum total water level relative to Singapore Height Datum is about 2.77 meters including all tidal constituents and 2.89 meters when excluding the SA and SSA constituents.