Physical processes contributing to storm surges generated by tropical storms

Storm surge (non-tidal water level) is usually defined as the difference between the observed water level and the predicted tide. Storm surges contribute to coastal inundation, erosion, and possible loss of lives. These effects are often amplified for countries in transition where coastal protection infrastructure is not as well developed. Physical processes that influence the non-tidal water level associated with storms systems can persists for up to 14 days, beginning 3–4 days prior to storm landfall and ceasing up to 10 days after landfall. Storms can also influence the water levels and currents both locally and many thousands of kilometres away from the landfall location. The components of a storm surge may include: (1) forerunner, an increase in the mean water level up to several days prior to storm landfall; (2) meteotsunami; (3) continental shelf seiches; (4)
edge waves with periods of ~six hours and speed 10ms-1, that move both directions along the coast; and, (5) continental shelf waves, which propagate in a single direction with the coast on their left (right) in the southern (northern) hemisphere meteorological forcing. In this paper, we present theory of the different processes together with field measurements and numerical modelling from Western Australia to highlight the processes that contribute to storm surges.