台风路径对长江口各汊道波高的影响

Influence of typhoon paths on wave height of the Yangtze River estuary

基于第三代海浪数值模式SWAN,将Holland梯度风场和CCMP背景风场叠加作为输入风场驱动模型,模拟0515号"卡努"台风的波浪传播过程,通过Jason-1卫星数据对模拟的风速和波高进行验证。在此基础上,将"卡努"路径向东平移构造出8条不同的台风路径,对不同台风路径下长江口各汊道的波高分布进行研究。结果表明,当台风路径范围覆盖整个长江口时,长江口各汊道产生的波高值较大,从长江口西侧和东侧经过时影响较小。当台风靠近长江口口门处穿过时,口门附近的北支、北槽和北港河段波高值较大;当台风靠近长江口南支附近穿过时,南支和南港河段波高值较大。当台风横穿长江口时,台风对长江口波高的影响口门外大于口门内,口门外波高最大值达到2～3 m,口门内波高最大值为1～2 m。

Combined with Holland gradient wind field and CCMP wind field,based on the third-generation wave numerical model SWAN,we carry out a numerical simulation of wind wave field under the influence of 0515 typhoon “Khanun”,and verify the simulated wind speed and significant wave height by the data of Jason-1 satellite.On this basis,we move the “Khanun” path eastward,establish eight typhoon paths including original path,and study significant wave height of each branch of the Yangtze River estuary under different typhoon paths.The results show that when typhoon paths cover whole Yangtze River estuary,significant wave height of each branch is larger,and from western or eastern side,the impact is relatively smaller.When typhoon paths near estuary entrance,wave height of northern branch and channel is larger.When typhoon paths near southern branch,wave height of southern branch and channel is larger.When the path of typhoon is crossing the Yangtze River estuary,the impact on outside entrance is larger than inside entrance.The maximum value outside the entrance is between 2 m and 3 m,and the maximum value inside is between 1 m and 2 m.