台风“天鸽”影响下珠江口水动力过程数值模拟研究

Numerical simulation of hydrodynamic processes in the Pearl River Estuary influenced by Typhoon"Hato"

【目的】探究台风“天鸽”影响下珠江口的水动力过程。【方法】基于FVCOM模型,采用非结构网格对珠江口及其附近海域进行数值模拟。【结果】珠江口八大出海口中的磨刀门受台风影响最大,最大增水为0.79 m,中部出海口在台风影响下增水0.30~0.65 m,外伶仃洋增水不超过0.20 m。受台风影响,表层流速极值的最大增幅达0.50 m/s,风暴潮最大表层流速是同时刻天文潮表层流速的2倍,风向随台风中心的移动在0~180°范围内变化。【结论】流速比潮位更早对台风做出响应,且受台风影响更大。台风对表层流速的影响明显大于对垂向平均流速的影响。台风“天鸽”运动轨迹的东北方向的风暴增水比西南方向的大,台风东北部地区所遭受的风暴潮灾害更加严重。

[Purposes]This study investigated the hydrodynamic processes in the Pearl River Estuary under the influence of Typhoon"Hato".[Methods]The hydrodynamic processes in the Pearl River Estuary and the nearby sea area were simulated using the FVCOM model based on an unstructured grid.[Findings]Among the eight outlets of the Pearl River Estuary,Modaomen was the one that most severely affected by the typhoon,with a maximum water increase of 0.79 m,followed by the central outlets(0.30-0.65 m),and the Wailingdingyang outlet(0.20 m).Under the influence of the typhoon,the maximum increase of surface current speed was 0.50 m/s.The maximum surface current speed of the storm surge was twice that of the astronomical tide at the same time.The wind direction varied within the range of 0-180°along with the movement of the center of the typhoon.[Conclusions]The current velocity responded earlier to the typhoon than the tide level and was more severely affected by the typhoon.The typhoon exerted a stronger influence on the surface current speed than on the vertical mean current speed.The storm surge in the northeast direction of the track of Typhoon"Hato"induced larger water increase than that in the southwest direction,and the area located in the northeast of the typhoon suffered more serious storm surge disaster.