甬舟航道潮汐潮流的数值模拟及特征分析

Numerical simulation and characteristic analysis of tidal current in the Yongzhou channel

基于非结构网格有限体积海岸海洋模型(FVCOM),建立了甬舟航道(121.78°~122.5°E,29.7°~30.1°N)及其附近海域的三维潮汐潮流数值模型。模拟结果同4个验潮站和2个连续测流站的观测资料吻合良好,表明该模型可以较好地反映甬舟航道海域内潮汐潮流的分布特征和变化规律。该航道海域的潮汐类型为不规则半日潮,最大可能潮差介于4.5~4.7 m之间;潮流类型为规则半日潮流,主要为往复流,只有航道岸边少部分表现为旋转流。最大可能流速分布在狭窄的深水道,而航道水深较浅的岸边流速较小。潮致余流介于1~15 cm/s,大致方向由东南向西北传播,并且在航道的西北和东南两侧分别形成两个明显的闭合环流。

Based on unstructured grid Finite Volume Community Ocean Model(FVCOM),a three-dimensional numerical model covering the Yongzhou channel(121.78°~122.5°E,29.7°~30.1°N) and its adjacent waters is established to simulate the tide and tidal current in this paper.The simulated results are in good agreement with the observational data from 4 tide gauge stations and 2 continuous current measuring stations,which reveals that the results of numerical simulation could well reflect the variation and distribution characteristics of the tide and tidal current movement in the channel area.The results show that it is irregular semi-diurnal tide in the channel with the maximum tidal range between 4.5~4.7 m.The tidal currents in the channel is generally reciprocating flow,and rotating flow only shows in a small part of the channel bank.The maximum velocity of tidal current is distributed in the narrow and deep waterways,while the velocity along the shallow bank is relatively smaller.The tidal residual current is between 1~15 cm/s generally propagating from southeast to northwest,and forms two obvious closed circulations on the northwest and southeast sides of the channel.