Assessing extreme monsoon and storm surge height projections along the Singapore Strait in a warming climate

Extreme sea level events driven by interactions among astronomical tides, storm surges, regional oceanographic variables, and sea level rise due to climate change can pose threats along the coastline of the Singapore Strait. This study undertakes a comprehensive analysis of tide gauge data, followed by the development of a regional storm surge and tide model using the Delft3D FM. The atmospheric forcings from the Singapore Variable Resolution – Regional Climate Model, which employs six global climate models from the CMIP6 climate projections, are used in this hydrodynamic model to compute monsoon and storm surge heights. The seasonal variability of atmospheric and oceanic conditions is investigated by comparing the annual climatological component derived from harmonic analysis with El Niño and the Southern Oscillation indices. The hindcast and projection simulations of monsoon ranges and storm surges are analyzed across different periods. Extreme monsoon and storm surge heights are estimated using various extreme value analyses to develop reliable coastal resilience plans in the Singapore Strait. Due to model uncertainties and climate variability, simple model averaging and weighted ensemble averaging approaches that integrate all models are used to capture extreme monsoon and storm surge heights, thereby improving projection accuracy.