Improved accuracy of storm surge simulations by incorporating changing along‐track parameters

Abstract

AbstractThe estimation of maximum storm surges along a coast is indispensable for emergency action planning, design, and adaptation of coastal infrastructure. The existing studies on the Bay of Bengal coast have used synthetic tracks with constant track parameters such as the maximum wind speed, radius of maximum wind, and central pressure to estimate the probable maximum storm surges. However, the analysis of the best tracks from the Joint Typhoon Warning Center during 1978–2019 shows that the track parameters vary from origin to landfall locations. The reported studies along the Bay of Bengal have failed to capture such variations and overestimated probable maximum storm surges due to constant track parameters. Therefore, this study proposes a methodology for estimating wind speed of various return periods and associated track parameters that vary along a synthetic track. The wind speed of different return periods is computed at each eye location using the probabilistic approach. Thus, the calculated wind speeds vary from origin to landfall locations, and such a pattern of wind speed variation is observed to be similar to the historical cyclones. The radius of maximum wind and central pressure is calculated using the regression equations derived from historical tracks. The accuracy of the proposed methodology is investigated by simulating the cyclones Thane and Vardah that occurred along the Tamil Nadu coast. The results suggest that the varying track parameters using the proposed methodology produce realistic surge values similar to parameters from best track data, and it overcomes the overestimation of surge heights. The proposed methodology is further utilized to analyse the maximum surge scenarios along the Tamil Nadu coast resulting from various track shifts and angles of attack. The proposed methodology is expected to improve the estimation of storm surges in other basins.