台风“利奇马”对长江口水通量影响的数值模拟研究

Numerical simulation of the impact of Typhoon"Lekima"on water flux in the Changjiang Estuary

在台风等极端天气影响下,河口水通量可能会在短时间内发生强烈变化。利用无结构有限体积海岸海洋模型FVCOM,研究了1909号台风“利奇马”对长江口水通量及分流比的影响。结果表明:台风“利奇马”可造成南槽持续30 h的净向陆水通量;受台风影响,北支、北港、北槽和南槽4个入海口台风的入海净水通量都呈现相似的减小—增大—减小—恢复的变化规律,总净入海通量也呈现类似规律,且变化幅度可超过60%;台风总体上增大了北侧支汊的净分流比,减小了南侧支汊的净分流比。

Under the influence of extreme weather,such as typhoons,the estuarine water flux may change strongly in a short time.In this study,the effects of Typhoon 1909"Lekima"on the water flux and split ratio in the Changjiang Estuary are investigated using the FVCOM model.The results show that Typhoon"Lekima"can cause the net landward water flux of the South Passage for more than 30 hours.Au the net water fluxes in the four inlets,i.e.North Branch,North Channel,North Passage and South Passage,show similar decrease-increasedecrease-recovery evolutions under the influence of the typhoon.The total net seaward water flux shows a similar evolution with its magnitude varying by more than 60%.The typhoon generally leads to the increase of net split ratio in the northern branch and the decrease of net split ratio in the southern branch.