“烟花”台风对钱塘江涌潮影响的数值模拟

Numerical simulation on the effect of Typhoon In-Fa on the Qiantang tidal bore

2021年7月25日“烟花”台风登陆于浙江舟山,恰逢天文大潮期,对钱塘江涌潮产生了较大的影响。为研究该强台风对涌潮的影响,建立了台风暴潮作用下的涌潮数学模型,采用“烟花”台风登陆期实测数据进行数学模型的验证,模型较好地复演了台风登陆期潮位和涌潮的变化过程。拟定计算方案以分离台风的直接和间接影响,计算结果表明:受“烟花”台风登陆时的逆风影响,台风对盐官河段涌潮的直接影响明显较间接影响小。“烟花”台风登陆时盐官潮差为3.59 m,盐官—老盐仓的涌潮传播速度增加7.7%,一线潮和回头潮的潮头高度平均增加0.30和0.22 m。“烟花”台风使盐官一线潮和老盐仓回头潮的潮到时间分别提前62和65 min。

Typhoon In-fa,making landfall in Zhoushan on July 25,2021,which coincided with the astronomical spring tide,had an effect on the Qiantang tidal bore.A typhoon model combined with a parametric hurricane model is developed to study the effect of the typhoon on tidal bore.Field data during the landfall of Typhoon In-Fa was used to verify model result and the changes of tidal level and tidal bore during the landfall of Typhoon In-Fa were well reproduced by the model.The model schemes were proposed to separate the direct and indirect effects of the typhoon.It is demonstrated that the direct effect of the typhoon on tidal bore is obviously smaller than the indirect impact due to wind field during the landfall of Typhoon In-Fa.Tidal range at Yanguan station during the typhoon is 3.59 m and the propagation speed of tidal bore from Yanguan to Laoyancang is increased by 7.7%.The heights of the line-shaped tidal bore and the back-flow bore have an average increase of 0.30 m and 0.22 m,respectively.The arrival time of the line-shaped tidal bore and the back-flow bore in Yanguan reach has an advance of 62 min and 65 min during the landfall of the typhoon.