The impact of typhoon Lekima on the marine dynamic environment in Dongjiakou harbor

LI Songlin; QI Xin; NIU Fuxin; TAO Yijun; JIANG Wanjun; YU Huaming

doi:10.13984/j.cnki.cn37-1141.2024.06.004

Abstract：The finger piers of Dongjiakou protrude out of the open ocean and are vulnerable to extreme sea state without the protection of breakwater.In this study,the abnormal changes and mechanism of hydrodynamic environment caused by typhoon Lekima captured by ADCP and bathythermograph at the front of Dongjiakou finger pier were analyzed,which could provide important reference for the predic-tion of berthing environment.It was found that the residual water level showed a"V"symmetric distri-bution with the maximum water reduction as the symmetry center,and its variation was dominated by wind.When the typhoon was close to Dongjiakou,the lag response time for storm surge was short.When the typhoon center was far away,it was the opposite.The observed residual current was general-ly less than 20 cm/s during typhoon Lekima,the coastal current had little threat to the port.The fore-head swell reached the pier 12 h ahead of the extreme wind speed,and the wave spectrum peak period of forehead swell was in the rolling resonance region of 300 000 ton crude oil carrier and 400 000 ton ore carrier berthed at the jetty which needed to be prevented in advance.Due to the mixing effect of ty-phoon waves,the bottom water temperature of the observation point rose about 1℃,and the thermo-cline was destroyed.Even after the typhoon,the bottom water temperature dropped slowly,with a cooling trend of 0.15 ℃/day.