大亚湾的潮汐动力学研究——I.潮波系统的观测分析与数值模拟*
作者简介:武文(1985—), 女, 山东省枣庄市人, 博士, 讲师, 近岸海洋动力与环境管理。Email: wenwu1985@ouc.edu.cn
收稿日期: 2016-08-23
要求修回日期: 2016-09-22
网络出版日期: 2017-06-01
基金资助
国家重点基础研究发展计划(2015CB452905)
中国博士后科学基金第8批特别资助(2015T80742)
Study on the tidal dynamics in Daya Bay, China — Part I. Observation and numerical simulation of tidal dynamic system
Received date: 2016-08-23
Request revised date: 2016-09-22
Online published: 2017-06-01
Supported by
Major State Basic Research Development Program (2015CB452905)
China Postdoctoral Science Foundation (2015T80742)
Copyright
文章作为大亚湾潮汐动力学系列研究的第一部分, 展现了大亚湾水动力的最新观测结果, 并借助于不规则三角网格海洋模式建立了高时空分辨率的三维潮汐潮流数值模型, 重现大亚湾潮位和潮流变化状况。结合实测资料与模拟结果, 得到了较以往更为精细的大亚湾潮波系统特征。浅水分潮, 尤其是六分之一日分潮在大亚湾内快速增长, 成为大亚湾潮波系统的显著特征。在大亚湾范和港M6分潮振幅达到与M4、S2分潮相同的量级。大亚湾外开阔海域的潮流以旋转流为主, 但进入湾内后潮流椭圆迅速扁平化, 往复流占据主导。在湾内主要潮流通道内, M6潮流椭圆主轴流速超过了M4和K1分潮。潮能通量分析揭示了大亚湾内高频分潮的强耗散, M6分潮的能量耗散率和半日周期内耗散的总能量均超过了M4、M2和K1分潮。观测到的欧拉余流表现出其湾内不一致的大小潮变化以及湾外所受沿岸流的影响。模拟出的欧拉余流则揭示了大亚湾内的余流多涡旋结构和水体弱交换能力。
武文 , 严聿晗 , 宋德海 . 大亚湾的潮汐动力学研究——I.潮波系统的观测分析与数值模拟*[J]. 热带海洋学报, 2017 , 36(3) : 34 -45 . DOI: 10.11978/2016078
This paper is the first part of our studies on the tidal dynamics in Daya Bay (DYB), China. It illustrates the recent field work results. We establish a three-dimensional, fine resolution, unstructured grid, coastal ocean model to reproduce the tides in DYB. The combination of observation and simulation in this paper gives a better description on the tidal dynamic system in DYB than previous studies. Shallow water tides, especially the sexta-diurnal tides increase fast in DYB, which become the most notable characteristic of DYB tidal dynamic system. In the Fanhe Harbour at the northeastern DYB, the amplitude of M6 tide reaches the maximum, at the same order as M4 and S2 tides. In the open sea outside DYB, the tidal current is dominated by a rotating shape; but once the current enters the bay, it turns to rectilinear quickly. In the main tidal channels, the magnitude of M6 tidal current is even larger than those of M4 and K1 tides. The distribution of tidal energy flux indicates larger tidal energy dissipation for higher frequency tides. In DYB, both the tidal energy dissipation rate and the net tidal energy dissipated in a semi-diurnal period are much larger by M6 tide than by M4, M2 and K1 tides. The observed Euler residual currents show different spring-neap variation in magnitude inside DYB, and reveal the influence of the coastal current outside the bay. The numerical simulation shows a multi-vortex of residual current, and indicates poor water exchange in the bay.
Fig. 1 Bathymetry map of Daya Bay. T1 and T2 indicate tidal elevation stations, C1-C6 indicate tidal current stations, and S1 is the section used for calculating tidal energy flux.图1 大亚湾地形图^T1和T2为水位站; C1~C6为海流站; S1为潮能通量计算断面 |
Fig. 2 Observed and simulated water levels and tidal-current velocity. (a) Time series of observed and simulated water level at Station T1, and (b) at Station T2. (c) Observed and simulated vertically-averaged northward tidal-current velocity at Station C2 of spring tides, and (d) of neap tides, with the measured water level at Station T1 used as reference图2 观测与模拟的水位和流速曲线^a. T1站实测和模拟水位序列; b. T2站实测和模拟水位序列; c. 大潮期间实测和模拟的C2站北向垂向平均流速(涨潮为正), 同时给出对应时刻T1站水位序列; d.小潮期间实测和模拟的C2站北向垂向平均流速(涨潮为正), 同时给出对应时刻T1站水位序列。图a蓝色方框中为图c对应的大潮期间水位和图d对应的小潮期间水位 |
Tab. 1 Harmonic constants for the main tides at stations T1 and T2表1 T1和T2站主要分潮的调和常数 |
分潮 | T1 | T2 | ||
---|---|---|---|---|
振幅 /cm | 迟角/º | 振幅/cm | 迟角/º | |
O1 | 27.62 | 245.4 | 27.28 | 244.1 |
K1 | 33.46 | 296.4 | 32.93 | 294.0 |
M2 | 36.71 | 257.0 | 33.58 | 254.0 |
S2 | 14.79 | 286.2 | 13.77 | 283.7 |
M4 | 13.17 | 288.5 | 8.98 | 280.1 |
MS4 | 10.81 | 341.7 | 7.22 | 333.3 |
M6 | 10.80 | 107.0 | 3.83 | 89.9 |
2MS6 | 10.69 | 175.2 | 3.78 | 159.2 |
Fig. 3 Vertically-averaged current vector (black arrows) and Euler residual current vector (red arrows) on spring tide (a) and neap tide (b), respectively. Numbers indicate the magnitude of Euler residual current图3 大潮(a)和小潮(b)期间垂向平均海流矢量(黑色)和欧拉余流矢量(红色) |
Fig. 4 Mesh grid of the Daya Bay model used in this study, and the basemap obtained from Google Earth图4 大亚湾模型网格示意图, 底图取自谷歌地球 |
Tab. 2 Errors of harmonic constants for the main tides between observation and simulation at stations T1 and T2表2 T1和T2站主要分潮调和常数模拟误差 |
分潮 | T1 | T2 | ||||
---|---|---|---|---|---|---|
振幅/cm | 迟角/º | Diff/cm | 振幅/cm | 迟角/º | Diff/cm | |
O1 | -0.11 | 0.10 | 0.11 | 0.12 | 0.30 | 0.17 |
K1 | -0.78 | 0.80 | 0.93 | -0.25 | -0.20 | 0.26 |
M2 | -0.22 | 0.20 | 0.24 | 0.11 | 0.20 | 0.17 |
S2 | -0.29 | -0.70 | 0.35 | 0.08 | 0.60 | 0.16 |
M4 | 0.09 | -0.20 | 0.10 | -0.01 | 0.40 | 0.07 |
MS4 | 0.10 | -0.50 | 0.13 | -0.02 | 0.90 | 0.12 |
M6 | -0.01 | 0.40 | 0.09 | -0.02 | -0.90 | 0.06 |
2MS6 | -0.25 | -0.50 | 0.27 | -0.02 | -0.10 | 0.02 |
Fig. 5 Comparison between simulated (red) and observed (black) currents during spring tides (u in the top panels and v in bottom panels)图5 大潮期模拟潮流(红色)与实测资料(黑色)对比^上排为东西向分量: a. C1; b. C3; c. C4; d. C5; e. C6。下排为南北向分量: f. C1; g. C3; h. C4; i. C5; j. C6 |
Fig. 6 Comparison between simulated (red) and observed (black) currents during neap tides (u in the top panels and v in bottom panels)图6 小潮期模拟潮流(红色)与实测资料(黑色)对比^上排为东西向分量: a. C1; b. C3; c. C4; d. C5; e. C6。下排为南北向分量: f. C1; g. C3; h. C4; i. C5; j. C6 |
Fig. 7 Co-tidal charts for (a) K1, (b) M2, (c) M4, and (d) M6 with colors for amplitude (units: m) and white lines for phase (units: °).图7 K1 (a)、M2 (b)、M4 (c)、M6 (d)分潮同潮图^填色表示振幅(单位: m); 白线表示迟角(单位: °) |
Fig. 8 Tidal current ellipse for (a) K1, (b) M2, (c) M4, and (d) M6 with colors for major-axis length (units: cm·s-1)图8 K1(a)、M2(b)、M4(c)、M6(d)分潮潮流椭圆分布^填色表示主轴流速(单位: cm·s-1); 白色椭圆表示潮流形态 |
Fig. 9 Tidal energy flux for (a) K1, (b) M2, (c) M4, and (d) M6 with colors for magnitude (units: W·m-1) in logarithm based on 10图9 K1 (a)、M2 (b)、M4 (c)、M6 (d)分潮潮能通量分布, 强度用以10为底的对数表示(单位: W·m-1) |
Fig. 10 (a) Vertically-averaged Euler residual currents with colors for magnitude of spring tide (units: cm·s-1) in logarithm based on 10. (b) Same as (a), except for neap tide. The black dots indicate in-situ tidal current stations图10 垂向平均的欧拉余流分布, 大小用以10为底的对数表示(单位: cm·s-1)^a. 大潮期间; b.小潮期间。黑点为观测期间布设的潮流站 |
The authors have declared that no competing interests exist.
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[7] |
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[9] |
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[10] |
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[11] |
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[12] |
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