Research@IITD - Storm surge modelling at IIT Delhi

Researchers at IIT Delhi have modified suitably the exiting Jelesnianski wind scheme for the Bay of Bengal for better representation of the cyclonic winds over the region. The distribution of cyclonic winds are computed based on the real-time information of radius of maximum winds and pressure-drop of the cyclone. The cyclonic winds are the primary forcing for generation of storm surges. Hence, it is very crucial for any numerical storm surge model to provide accurate cyclonic winds as an input for better prediction of storm surges along the coast.

The researchers validated theJelesnianskiwind scheme extensively using buoy winds for the cyclones formed in the Bay of Bengal since 2010. It was found that the cyclonic winds computed from the scheme showed an underestimate in the magnitude and also a mismatch in its direction. Hence, the wind scheme was suitably modified based on the buoy observations available at different locations using a power law which reduced the exponential decay of winds by about 30%. The storm surges are computed using stand-alone ADCIRC and coupled ADCIRC + SWAN models with the modified wind scheme.

Prof A D Rao, former Head of the Center for Atmospheric Sciences and one of the authors of the study says that the simulated storm surges using the modified wind scheme agree very well with the observations. However, this needs to be further verified for more number of cyclonic events in the future.

The models which are developed at IIT Delhi are being used by many Indian Ocean rim countries including India Meteorological Department for their operational purpose. IIT Delhi is currently involved in improvement of storm surge predictions using numerical models.

The above study, supported by the Indian National Centre for Ocean Information Service (INCOIS), has been published in the journal “Natural Hazards”.