Numerical modelling of waves and surge from Cyclone Chapala (2015) in the Arabian Sea

Abstract

Cyclones cause significant loss of life and damage to properties, ecosystems and marine structures and facilities. Cyclone modelling results are used for deriving robust design conditions for coastal and marine structures and facilities. The results are also used for emergency planning and decision-making to estimate potential loss of life, damage to properties and marine facilities and to develop rescue and mitigation measures and plan clean-up operations. Royal HaskoningDHV (hereafter RHDHV) has set up regional tidal hydrodynamic and wave models covering the Arabian Sea to provide data to address the above issues. Over the course of a number of studies a total of 30 major cyclones have been identified in the Arabian Sea since 1945. Cyclone Chapala (28 October – 4 November 2015) was found to be the second strongest cyclone event since 1945 (the strongest being Cyclone Gonu in 2007). As less information is available on Cyclone Chapala, this paper has concentrated on this event to illustrate the use of numerical modelling to simulate waves and surge generated by cyclones. The MIKE21 model suite has been used to investigate this cyclone and sample results from the wave and surge modelling are presented in this paper for illustration purposes. The models could be used to simulate any cyclone generated within the Arabian Sea. The methodology described in this paper for modelling waves and surge in the Arabian Sea could also be applied to simulate this type of events at other sites around the world.