Modeling Storm Surge and its Associated Inland Inundation Extent Due to Very Severe Cyclonic Storm Phailin

Abstract

A hindcast simulation of storm surge and inundation from tropical cyclone Phalin, which made landfall at Odisha, India, on 12 October 2013, was carried out using ADCIRC model. Model-simulated inundation extent matched well with field surveys at Ganjam, Odisha, within a few days of landfall. Further, the model reproduced the temporal evolution of the surge residual with respect to observations from a tide gauge at Paradip (correlation 0.8, RMSE 0.26 m). However, the model marginally underestimated the magnitude with respect to observations, which can be attributed to the lack of wave setup in the model and uncertainty in wind and pressure information. The experiment also involved the use of two idealized scenarios, that is, variation of landfall timings with the ebbing and high tide phase. These scenarios were required for better understanding the sensitivity of inundation to the phase of tide in the model. Simulation with landfall at flooding (ebbing) tide showed greater (lower) inundation than the real scenario. Results from idealized scenarios confirmed the significance of the accuracy needed in forecasting landfall time. Our results clearly indicate that the overall performance of the model is good and therefore is of potential use as a tool to forewarn disaster management authorities.

Keywords:

• ADCIRC
• inundation
• Phailin
• residual
• storm surge
• wave setup

Acknowledgements

The authors are thankful to the Integrated Coastal and Marine Area Management Project Directorate team for conducting the post-storm survey for inland extent of inundation. Thanks are also due to the ADCIRC development team for providing the model. This is INCOIS contribution 231.