董家口港突堤码头缺乏防波堤掩护,易受极端海况影响.本研究分析了董家口港突堤码头前沿的ADCP(Acoustic Doppler Current Profiler)和温深仪所捕捉到的台风"利奇马"引起的港区水动力环境异常变化,可为突堤码头船只靠泊环境预报提供重要参考.本文主要结论有:"利奇马"台风期间董家口港风暴潮位以最大减水为对称中心呈"V"型分布,其变化受风速主导,台风中心接近董家口时,风暴潮位滞后响应时间较短,台风中心远离时,风暴潮位滞后响应时间较长.台风期间观测余流普遍小于20 cm/s,对港口威胁较小.码头有效波高受风区影响显著.码头位置"先头涌"先于风速极值12 h出现,且涌浪谱峰频率位于30万吨原油船和40万吨矿石船的横摇谐振区内,需提前加以防范.台风浪的混合作用使得观测点底层海水升温约1℃,由于温跃层受到破坏,台风过后底层水温降温缓慢,降温趋势为 0.15℃/天.
The impact of typhoon Lekima on the marine dynamic environment in Dongjiakou harbor
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.
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