Numerical analysis on the effect of wave boundary condition in storm wave and surge modeling for a tropical cyclonic condition

In a swell dominated region like the Northern Indian Ocean basin, the effect of pre-existing waves will play a significant role in the non-linear wave-wave interactions during cyclonic conditions, where the sea is dominated with high-frequency waves. Hence, to include such complex phenomenon into the numerical model, the present study aims at forcing a pre-run two-dimensional wave spectral output from an unstructured global coarser domain as a wave boundary condition to a finer regional domain. The storm wave and surge simulations were performed for the duration of cyclone Phailin (2013). A coupled (ADCIRC + SWAN) model was used for both, generating the spectrum, as well as the estimation of surge and wave attributes. Additionally, both storm wave and surge were simulated without considering the nested wave boundary condition, followed by the comparison and analyses of the modeled results with the field data. The investigation showed that the inclusion of wave boundary condition in the model resulted in closer agreement of the simulated wave parameters with the observed field data. The residual surge results also correlated well with the in-situ measurements, while the spatial representation of maximum water levels essentially revealed the spread of surge and its associated inundation.

Automated summary

In a region like the Northern Indian Ocean basin, the study focused on the non-linear wave-wave interactions during cyclonic conditions by incorporating pre-existing wave effects into the numerical model. The results showed that using wave boundary conditions improved the agreement between simulated wave parameters and observed field data, as well as correlated well with in-situ measurements of surge.