Comparative study on storm surge processes caused by typhoons with similar tracks

Based on MIKE 21 model and Holland typhoon wind field model, the wind field and pressure field during No. 1909 Typhoon Lekima and No. 0509 Typhoon Matsa are constructed, and the corresponding storm surge process is simulated. The results show that the increase of water near the typhoon center changes significantly and the storm surge in the northeast of Zhejiang Province is greater during the typhoon landing. Affected by the typhoon intensity, the high value area of storm surge during Typhoon Lekima is larger, and the maximum difference of storm surge during two typhoons in some sea areas is close to 1. 0 m. The large value of tidal Euler residual current is mainly distributed in the sea area within a depth of 100 m and a velocity of more than 20 cm/s. Meanwhile, the Euler residual circulation exists in the coastal sea areas of Jiangsu Province and the northeastern sea areas of Taiwan Province. The value of Stokes residual current in the offshore during Typhoon Lekima is generally lower than that during Typhoon Matsa. The Stokes residual current term plays a certain leading role in the short-term transport process of net material in the coastal shallow water areas such as the Yangtze River Estuary, Zhejiang Province and Fujian Province during the typhoon. The empirical mode decomposition (EMD) method and Hilbert transform are used to analyze the characteristics of storm tide level at typical stations. It is found that the IMF1 mode at stations is in good agreement with the astronomical tide level. The water depth and the maximum power spectral density of IMF3 mode show a high correlation, and with the increase of water depth, the maximum power spectral density of IMF3 mode gradually increases.