Sri Lanka is an island bounded by Indian Ocean and located near the Bayof Bengal.
Most of the times the coastal region of Sri Lanka is affected to · Tropical cyclones generated in the southern part of Bay ofBengal· Tropical cyclones generated in Arabian Sea (least extent). Tropical cyclones form generally during the latter part of thepost-monsoon season or early part of the pre-monsoon season. A large percentageof cyclones generated in the Bay of Bengal and Arabian Sea do not make landfallin Sri Lanka due to the nearby proximity of Sri Lanka to the equator and otheratmospheric dynamics related with cyclones (Wijethunge, 2013)During the last centurysixteen cyclonic or severe cyclonic storms have made landfall in Sri Lanka accordingto the Department of Meteorology, Sri Lanka. Storm surges, extreme winds andheavy rainfalls occurred due to these cyclonic weather conditions.
Storm surge is an abnormalrise in the sea level over the astronomical tide during the period of a typicalcyclone condition causing from strong onshore winds or reduced atmosphericpressure or combination of both. Tropical cyclone-generated storm surges areamong the supreme deadly and costly global catastrophes. The combination ofstorm surge with the high tide is highly dangerous and killed thousands ofpeople all over the world. Storm surges generated due to the tropical cyclonesconsidered as one of the most devastating coastal maritime hazard. From abroader perspective, storm surges may have killed as many as 2.6 million peoplearound the world during the past 200 years.
The majority of the stormsurges are found in the Western North Atlantic, followed by Australia/Oceania,the Western North Pacific, and the Northern Indian Ocean. The Bay of Bengalconsistently observes the world’s highest surges and observes the mostcatastrophic surge impacts. Those severe surge events have inflictedextraordinary economic losses and considerable damage to the property due tothe cyclone induced storm surge inundation on low lying coastal lands (Wijethunge, 2015)Predictions of storm surgehave been made using both dynamical and statistical methods.
The earliestefforts at dynamical modelling were obstructed by the lack of meteorologicalobservations over the water and by the over simplifications needed to make thedynamics computationally tractable. This led researchers to develop empiricaland statistical relationships between wind and pressure fields and water-levelchanges based on relationships derived from simplified theory and equations ofmotion.Total sea water levelconsists of storm surge, astronomical tide, waves and fresh water input(seasonal sea level change). This research project will provide a detailedanalysis about the estimation of storm surge heights at Colombo coastline fordifferent return periods.