围填海对连云港海区天文潮及风暴潮的影响分析

本文研究了围填海对连云港海区海洋动力环境的影响,通过分析连云港海洋站的实测数据,给出了连云港近海的水动力特征;基于ADCIRC建立了渤黄海的潮汐和风暴潮模型,利用海洋站的潮位资料和增减水资料验证了模型的适用性,模拟了填海前和填海后的潮位,分析了不同情况下潮汐的变化;并利用该模型研究了围填海对可能最大风暴潮的影响。研究结果表明：围填海引起了分潮振幅的变大,尤其是M₂分潮,最大增幅能达到5.5 cm;围填海对风暴潮增减水有一定影响,距离填海区越近影响越大,徐圩港区周边可能最大增水极值变化范围为-27～18 cm。     

海口湾人工填海前后冲淤演变数值模拟

为了解近年的人工填海工程主要包括南海明珠项目、葫芦岛、秀英港扩建工程等人工填海工程对海口湾冲淤变化的影响,基于FVCOM海洋数值模型,对研究区人工填海前后潮流场、波浪场及冲淤变化进行了数值模拟。人工填海后,综合各条件下的冲淤情况,海口湾受潮流和波浪共同作用大部分区域处于淤积状态,年淤积量预测值为0.1~1.0m;白沙角等局部区域处于侵蚀状态,年冲刷量预测值为0.1~0.3m;受海口湾人工填海工程的影响,秀英港航道的水动力条件减弱,对通航条件改善有利,需加强航道的水深监测和定时的清淤工作;在南海明珠人工岛南侧波影区泥沙堆积会形成向海的舌状的突出体,其两侧海岸形成侵蚀后退带,需人工补沙等措施以保证岸线稳定。     

渤海风暴潮对沿岸增水的影响及灾害风险评估

近10多年来,我国围填海工程发展迅速,渤海海岸线变化明显,岸线变化会改变潮波传播并影响风暴潮增水。基于FVCOM海洋动力学模型,利用潮汐和风场强迫,建立了渤海风暴潮模型,根据2000年岸线和2010年岸线,分别模拟了包括台风风暴潮和寒潮风暴潮在内的4次典型风暴潮过程,对模拟数据和实测数据进行统计分析,模拟结果与实测数据基本一致。研究了岸线变化前后,渤海风暴潮对近岸増水的影响,并对曹妃甸港、天津港和黄骅港的风暴潮增水灾害进行了风险评估。     

渤海湾大规模围填海导致的岸线变化及潮流场响应分析

本文以21世纪初渤海湾大规模的围填海工程为背景,对2000-2015年典型年份的卫星遥感影像资料进行了岸线提取,并分析了其时空演变规律.以此为基础,建立了不同岸线及地形条件下的渤海湾水动力数值模型,计算结果与塘沽、黄骅港和东风港三个潮位观测站的实测数据吻合良好.模拟结果显示:渤海湾大规模围填海工程的建设使得三个主要工程区(曹妃甸工业区、天津港及黄骅港)附近的潮流运动更加剧烈,但对于渤海湾离岸潮流场的影响不大.M2分潮流速及流向变化明显,其最大流速方向与建筑物布置、深水航道航线方向一致.黄骅港挡沙堤的建设使其附近流场出现局部涡旋,导致潮流以旋转流的形式运动.     

9711号台风对日照近海悬沙浓度影响的数值模拟

运用改进的椭圆形风场模型,模拟了9711号台风所经地区风场、气压场的变化过程;将椭圆形风场模型结果结合SWAN波浪模型,计算9711台风过程的波要素;运用COHERENS三维水动力模式,对渤、黄海主要的4个潮分量进行了调和分析,建立渤、黄海天文潮预报模型,并采用三级嵌套模型计算并验证分析了日照近海的水文动力环境;运用基于COHERENS发展的水动力悬沙模型COHERENS-SED,计算分析了9711天气过程、仅考虑潮流作用以及累年平均波要素和一般天气情况(累年平均风场、标准大气压)下的悬沙数值模拟.结果表明:考虑潮流、一般波浪和天气因素共同作用下的水体含沙浓度比仅考虑潮流作用下的水体含沙浓度提高40%～100%的幅度;考虑9711号天气过程以及产生的台风浪作用下的水体含沙浓度比一般波浪和天气因素作用下的水体含沙浓度提高约4倍的幅度.     

渤海岸线及水深变化对水动力影响的数值模拟

为探究渤海岸线及水深变化对水动力的影响,基于Delft3D水动力学模型,选用2003年和2015年作为围 填海前后的典型年份,建立了围填海前后岸线及水深条件下的渤海三维水动力模型,并对水动力场进行了模拟。通过对围填海前后潮波和潮余流的分析,得到了岸线及水深变化对渤海水动力场的影响。结果表明:填海后,岸线及水深变化会对渤海主导分潮M₂分潮产生较大影响,秦皇岛附近无潮点向西北方向偏移,渤海海域M₂ 分潮振幅总体减小;潮致余流场受岸线及水深变化影响较大,其中渤海湾曹妃甸港南部形成复杂的涡流,沿岸海域余流增大;滨海新区附近形成多个小范围环流,且天津港到黄骅港北部沿岸海域2015年余流比2003年增加3~5 cm/s;黄骅港南部形成一个逆时针环流,并且该处余流减小2~5 cm/s。辽东湾辽河口附近由于水深增加导致余流减小2~7 cm/s。莱州湾黄河口附近的逆时针环流向东南方向移动,黄河口北部余流略有减小,东南部余流明显增大,增加量最多能达到9 cm/s。刁龙嘴南侧顺时针环流减小,北侧顺时针环流增大4~9 cm/s。     

围填海工程对半封闭海湾水动力环境的影响

为研究围填海工程对海湾水动力环境的影响,本文基于二维数值模型MIKE21,建立了东山湾附近海域的潮流模型。对比观测数据发现,大潮期间的最高、最低潮位模拟误差在6 cm以内,小潮期间的误差相对较大;流速和流向的模拟误差在9%左右,最大误差出现在转流时刻;总体来看,模拟结果与观测数据吻合良好。在此模型基础上,研究了东山湾围填海前、后潮流动力、水体半交换时间和纳潮量等水动力要素的变化。结果表明:围填海后大范围的涨落流态与围填海前保持一致,大体上仍然呈现S-N走向,涨潮流偏N向,落潮流偏S向,往复流特征较为明显;从局部流场来看,涨落潮流场发生了一定的变化,围填海区域南、北两侧的流矢变化较为明显,涨潮流矢由偏N向改为偏E向,而落潮流矢由偏S向改为偏W向,同时受到围填海区域岸线的遮蔽效应,围填海南、北两侧水域的流速也有一定减弱,而西侧的流速则有一定增强;围填海实施前的水体半交换时间为220.5h,实施后时间为239.4 h;纳潮量变化为–2.5%左右。研究表明,围填海工程对东山湾水动力环境的影响主要集中在工程区域附近,其对泥沙冲淤、生态环境等的影响将在后续研究中进一步探讨。     

围填海工程对近岸海域海洋环境影响的研究进展

随着沿海地区大量人口的涌入,国内外沿海各地纷纷兴起围海造陆的热潮。大规模的围填海工程在解决用地不足的同时也给近海海洋环境造成了深远的影响,这引起了许多学者的关注。本文分别从围填海对近海海域地形地貌、水动力环境以及海洋生态环境等方面阐述围填海工程对近海海洋环境影响,并重点分析数值模拟在海洋水动力环境影响分析中的发展应用。最后根据围填海工程对近海海洋环境影响的研究现状与进展趋势,提出围填海工程对近海海洋环境影响研究的建议以及今后研究的方向,未来应系统的研究大规模围填海工程对近海海域的长期影响,考虑多项因素,全方位地论述研究的方法,以便于科学合理的开发利用海洋资源。     

罗源湾多年围填海工程对水动力环境的累积影响研究

由于滩涂开发和临港工业建设的需要,罗源湾内围填海活动频繁,但长期以来多个围填海工程对湾内水动力环境的累积效应十分明显。本研究以围填海累积影响下的罗源湾水动力环境变化为研究对象,通过MIKE 3模型,分析了罗源湾3个典型围填海时期岸线与地形条件下的纳潮量和水交换能力变化。结果表明,多年实施的大量围填海工程对罗源湾的纳潮量和水交换的累积效应显著。1996和2012年的海湾全潮平均纳潮量与1960年代相比,分别减少了约20.59%和28.38%,湾内30d的平均水交换率则分别减少19.17%和21.42%,半交换时间延长了约1.74和2.42d。由此可见,频繁的围填海工程对罗源湾水动力环境的累积影响较大。     

湛江湾填海工程对水动力条件的影响预测

建立了湛江湾二维全流水动力学模型,模拟了湛江湾宝满码头填海工程前、后的水动力场。通过工程前后的流场比较,预测了围填工程对水动力场的影响,并优选了围填方案。     

Year-to-year change in water exchange characteristics in a semi-enclosed bya,Lake Hamana

The year-to-year change in characteristics of water exchange between Lake Hamana, a semi-enclosed bya, and the adjacent open sea is investigated.The destruction of the bay mouth by a typhoon in 1953 and subsequent stabilization work on the bay mouth from 1954 to 1973 resulted in an increase in the tidal prism volume of the bay (Mazda, 1983). In the present paper, a simple model has been constructed in which the magnitude of water exchange depends on the tidal prism, and using this model, the year-to-year increase in salinity of the bay water after 1953 can be well explained. Consequently, it can be said that the salinity increase after 1953 is a result of a progressive increase in water exchange caused by successive changes in topography of the bay mouth.The extent of water exchange in Lake Hamana, which varies seasonally, has increased gradually since 1953, and became stable after about 1967. For instance, at present the turnover time of the bay for exchange with open sea water reaches a maximum (2.9 months) in January and a minimum (0.9 month) in October, while in 1955 it is estimated to have been about 2.5 times that at the present time.     

Swell-dominant surface waves observed by a moored buoy with a GPS wave sensor in Otsuchi Bay,a ria in Sanriku,Japan

Real-time monitoring of wind and surface waves in Otsuchi Bay, Iwate, Tohoku, Japan, commenced in October 2012, using a mooring buoy with an ultrasonic anemometer and a single-mode GPS wave sensor. Wind and wave data are distributed hourly in real time via the Internet along with a chart of their time series. We analyzed data monitored in the first 3 months in order to assess the variability and occurrence of wind and waves and to elucidate the main reasons for wave variation in Otsuchi Bay. The monitoring data revealed that surface waves in the bay were predominantly affected by swells propagated from the northeastern offshore region and that the wave height was significantly correlated with the component of wind velocity toward Otsuchi Bay in the northeastern offshore region that faces the bay mouth. The offshore wind field was expected to provide information useful for predicting coastal waves in a ria bay in Sanriku such as Otsuchi Bay. However, it should be emphasized that the horizontal distribution of the offshore wind field which has a significant effect on the surface waves in a ria bay depends heavily on the topographic shape of the bay.     

The effects of a bypass dunefield on the stability of a headland bay beach: A case study

This paper presents a case study on the modelling of a headland bay beach influenced by sediment input from migrating coastal dunes. The study area is the region around the town of Ingleses on Santa Catarina Island, Santa Catarina state, South-Eastern Brazil. Ingleses has been threatened by nature at two different fronts. At the north-eastern side of the town lies Ingleses Beach, a headland bay beach which seems to be subject to persistent erosion in recent years. On the south-western side the town is threatened by a migrating dunefield, which is encroaching onto houses and infrastructure, but which has not reached the beach in the past 70 years. A second dunefield in the area does not pose a direct threat to the town, but passes it on the eastern side and forms an important influence on the development of the beach. The sediment influx rate from this dunefield to the beach is 10,000 m³/year. To investigate the effect of the dunefields on the morphodynamic system, a numerical model has been created using the software packages SWAN and UNIBEST and the static equilibrium bay shape was determined by the software package MEPBAY. The result of the long-term scenario as predicted by UNIBEST agrees rather well with the static equilibrium bay shape found with MEPBAY. This provides sounds basis for the credibility of both models. Consequently, the predicted evolutional trend of the shoreline seems plausible.     

石岛湾东北侧水道对环境影响的数值模拟

随着经济的发展,石岛湾的环境污染日趋严重。为了改善其海洋生态环境,并增加航运能力,开挖入海通道是非常必要的。通过对石岛湾海水交换率、海水半更新期的估计,以及湾内示踪物浓度分布的数值模拟,研究了开挖多种入海通道的预案,模拟结果显示:石岛湾东北部开挖宽300m或500m水道方案的水体交换效果不及开挖宽800m的方案,后者可明显降低海湾东部的示踪物浓度,有利于湾内的水交换。而开挖的水道宽度增至1000m或1500m后也不会再更加明显地改善石岛湾的水环境,说明可选择开挖宽800m水道的方案。     

人工半封闭港湾有孔虫埋葬群空间分布研究--以江苏连云港港区为例

连云港港区60个表层沉积样品的定量分析表明,与港区水动力、底形等沉积环境条件相适应,该区有孔虫埋葬群可分为口门、湾中、湾顶三大群个组合,并可进一步区分出若干六个亚类组合：（A）湾项浅水区——丰度值最低,胶结壳有孔虫含量最高,活体含量高;（B）鸽岛沉积区——与A紧邻,但以丰度值高相区别;（C）西岸码头深水区——水深,丰度高,活体少,浮游个体多;（D）东侧浅水区——水浅,埋葬群特征与C相近;（E）涨潮三角洲区--沉积物粒径小,丰度高,胶结壳含量最低;（F）口门高能区——以沉积物粒径较低区别于E区.     

Investigation of wave characteristics in a semi-enclosed bay based on SWAN model validated with buoys and ADP-observed currents

In this study, the simulating waves nearshore (SWAN) model with a locally refined curvilinear grid system was constructed to simulate waves in Jervis Bay and the neighbouring ocean of Australia, with the aim of examining the wave characteristics in an area with special topography and practical importance. This model was verified by field observations from buoys and acoustic Doppler profilers (ADPs). The model precisions were validated for both wind-generated waves and open-ocean swells. We present an approach with which to convert ADP-observed current data from near the bottom into the significant wave height. Our approach is deduced from the Fourier transform technique and the linear wave theory. The results illustrate that the location of the bay entrance is important because it allows the swells in the dominant direction to propagate into the bay despite the narrowness of the bay entrance. The wave period T p is also strongly related to the wave direction in the semi-enclosed bay. The Tp is great enough along the entire propagating direction from the bay entrance to the top of the bay, and the largest Tp appears along the north-west coast, which is the end tip of the swells’ propagation.     

Annual and interannual variations of sea-level anomaly in the Bay of Bengal and the Andaman Sea

Annual and interannual variations of sea-level anomaly (SLA) in the Bay of Bengal and the Andaman Sea are investigated using altimeter-derived SLA data from 1993 to 2003. It is found that the SLA annual variation in the study area can be divided into three phases with distinctive patterns. During the southwest monsoon (May-September), positive SLA presents in the equatorial region and extends northward along the eastern boundary of the bay, and the SLA distribution in the interior bay appears to be high in the east and low in the west with two cyclonic cells developing in the north and south of the western bay respectively, between which an anticyclonic cell exists. During the early northeast monsoon (October-December), the whole bay is dominated by a large cyclonic cell with the pattern of high SLA in the east and low in the west still retained, and the SLA distribution outside the bay is changed in response to the reversal of the Indian Monsoon Current (IMC) in November. During the late northeast monsoon (January-April), a large anticyclonic cell of SLA develops in the bay with negative SLA prevailing in the equatorial region and extending northward along the eastern boundary of bay. Therefore, the SLA distribution in the interior bay reverses to be high in the west and low in the east. It is suggested that the SLA annual variation in the bay is primarily driven by the local wind stress curl, involving Sverdrup balance while the abrupt SLA variation during the peak of northeast monsoon may be partly caused by the semiannual fluctuation of wind in the equatorial region. This fast adjustment in the interior bay is induced by the upwelling coastal Kelvin wave excited by the decay of Wyrtki jet during December through January. Besides the annual variation, in the bay, there are obvious SLA fluctuations with the periods of 2 and 3~7 a, which are driven by the interannual variability of large-scale wind field in the equatorial region. The coastal Kelvin wave also provides an important link for the SLA interannual variation between the equatorial region and the interior bay. It is found that the El Nio-Southern Oscillation (ENSO)-induced influence on the SLA interannual variation in the interior bay is stronger than the Indian Ocean dipole (IOD) with the associated pattern of low sea-level presenting along the periphery of the bay and high sea-level in the northeast of Sri Lanka.     

Surface current response to wind and plumes in a bay-shape estuary of the eastern Yellow Sea: Ocean radar observation

Response of surface subtidal current to wind and outflow plume in the bay-shape estuary, which had been artificially made by the Samangeum reclamation dike with two sluices in the west coast of Korea, was examined using the ocean radar-derived current data obtained in the summer 2010. The southerly wind was dominant due to Asian summer monsoon and the outflow plume water was discharged by the gate operation of the Shinsi and Garyeok sluices separated by 11 km into the study area that are opened in a southwestward direction. The monthly-mean flow pattern consisted of the westward outflow currents around the two sluices, the along-dike currents between the two sluices and the northward currents in the outer bay. Based upon the complex correlations of subtidal current to wind and outflow jets we explained that the northward mean current in the outer bay be formed by both the southerly wind-driven current and the geostrophic current by mean pressure setup due to the Ekman transport and plume water accumulation in the inner bay, and the along-dike mean current may be induced by the southerly wind that generates on-dike currents in the central region of study area and leads to pressure setup toward the dike between the two sluices. Combination of outflow jets, wind and coastline configuration affects variations of subtidal surface current in the inner bay. Variability of subtidal current in the outer bay is dominated by wind variation. The southerly wind produced the northward current in the outer bay though the outflow plumes from the two sluices turned clockwise from the inner to the outer bay due to the geostrophic balance when the wind was calm. The wind factor was from 2% to 7% depending on the amount of freshwater outflow and wind speed. Occasionally, when plume water discharges were large and the southerly wind was stronger than 5 m/s, a large eddy with a closed loop current was produced off the Shinsi sluice.     

The Influence of Winds and Tides in the Formation of Circulation Layers in a Bay, a Case Study: Concepción Bay, Chile

Horizontal water velocities were measured using three current meters moored at the levels of 5, 18, and 30 m depth in the oriental side of Concepción Bay (36°40′S; 73°02′W), an almost rectangular, shallow bay off central Chile, connected with the open sea through two mouths.The large momentum transfer from the wind to the water causes variations of the internal volume of the bay generating circulation layers having almost anti-parallel directions. Northerly winds carry superficial water into the bay, causing a compensating flow leaving the bay near its bottom. Winds from the SW, on the other hand, cause an outgoing circulation layer in the surface and a circulation layer entering into the bay near the bottom. During wind calm periods, longer than 12 h, the two layers disappear, leaving a current system comprising only one circulation layer. The response time necessary for the generation or dissipation of these layers, which fluctuates between 1 and 7 h, depends on the initial conditions of the bay and on the intensity, direction and persistence of the wind.