吕宋海峡M2内潮生成与传播数值模拟研究

本文在z坐标海洋数值模式HAMSOM中引入了内潮黏性项(Interhal-tide viscosity term),将之运用到吕宋海峡M2内潮的生成与传播过程的数值模拟研究.研究结果表明:(1)在250 m以浅,吕宋海峡产生的M2内潮振幅于温跃层处最大,岛坡附近的内潮明显强于别处,且最大振幅可达到40 m左右;(2)M2内潮的生成源主要集中在伊特巴亚岛西北、巴丹岛西南以及巴布延群岛西北的岛坡;(3)海峡产生的M2内潮向东西2个方向传播.巴丹岛以西的西向能量在吕宋海沟斜向下传播,在到达恒春海脊附近发生反射返回海面,到达海面后再次反射回海底,在此过程中,有高模态的内潮被激发,不同模态间有相消干涉的现象产生.西传的内潮能量分为2支进入南海,产生于巴布延群岛西北的能量分支直接向西南折转进入南海海盆,而产生于伊特巴亚岛和巴丹岛岛坡附近的主要能量则以束状向南海陆架传播,在到达118°E后部分能量折向西南的海盆,其余的能量则沿西北方向传入中国近岸,陆架陆坡地形起着重要的耗散作用.伊特巴亚岛西北有最大的能量产生,向东北传入太平洋.在122°E以东,能量主要以束状向东南传入太平洋.     

吕宋海峡M2内潮生成与传播数值模拟研究

本文在z坐标海洋数值模式HAMSOM中引入了内潮黏性项(Internal-tide viscosity term),将之运用到吕宋海峡M2内潮的生成与传播过程的数值模拟研究。研究结果表明:(1)在250 m以浅,吕宋海峡产生的M2内潮振幅于温跃层处最大,岛坡附近的内潮明显强于别处,且最大振幅可达到40 m左右;(2)M2内潮的生成源主要集中在伊特巴亚岛西北、巴丹岛西南以及巴布延群岛西北的岛坡;(3)海峡产生的M2内潮向东西2个方向传播。巴丹岛以西的西向能量在吕宋海沟斜向下传播,在到达恒春海脊附近发生反射返回海面,到达海面后再次反射回海底,在此过程中,有高模态的内潮被激发,不同模态间有相消干涉的现象产生。西传的内潮能量分为2支进入南海,产生于巴布延群岛西北的能量分支直接向西南折转进入南海海盆,而产生于伊特巴亚岛和巴丹岛岛坡附近的主要能量则以束状向南海陆架传播,在到达118°E后部分能量折向西南的海盆,其余的能量则沿西北方向传入中国近岸,陆架陆坡地形起着重要的耗散作用。伊特巴亚岛西北有最大的能量产生,向东北传入太平洋。在122°E以东,能量主要以束状向东南传入太平洋。     

长江口、杭州湾及其邻近海区Lagrange环流的数值模拟研究Ⅰ——正压环流

将长江口、杭州湾及其邻近海域作为研究整体,建立该海区的三维Lagrange正压环流的分阶数值模式,综合考虑径流、东中国海背景环流、风应力和M2,S2,O1,K1 4大天文分潮的综合作用,运用流速分解法将环流分为正压梯度流、风生流、潮致余流及零阶环流的非线性耦合流等4个分量,模拟了冬夏两季长江口、杭州湾及其邻近海区的Lagrange正压环流结构.结果表明,零阶环流受东中国海背景环流控制;潮致余流是该海区一个重要分量;杭州湾内正压环流主要由风生流和潮致余流控制.     

吕宋海峡M2内潮的三维数值模拟

A three-dimensional isopycnic-coordinate internal tidal model is employed to investigate the generation,propagation, vertical structure and energy conversion of M2 internal tides in the Luzon Strait(LS) with mooring observations. Simulated results, especially the tidal current amplitudes, agree well with observations,demonstrating the reasonability and accuracy of the model. Results indicate that M2 internal tides mainly propagate into three directions horizontally, i.e., eastward towards the western Pacific Ocean, westward towards the Dongsha Island and southwestward towards the South China Sea Basin. In the horizontal direction, tidal current amplitudes decrease as distance increases away from the LS; in the vertical direction, they show an obvious decreasing tendency with depth. Between the double ridges of the LS, a clockwise gyre of M2 baroclinic energy flux appears, which is caused by reflections of M2 internal tides at supercritical topographies, and resonance of M2 internal tides happens along 19.5° and 21.5°N due to the heights and separation distance of the double ridges. The total energy conversion in the LS is about 14.20 GW.     

渤海、黄海、东海潮流、潮能通量与耗散的数值模拟研究

基于ROMS海洋数值模式,对渤海、黄海、东海的潮汐、潮流进行数值模拟,模拟结果与91个沿岸验潮站的实测结果拟合较好。研究表明,渤、黄、东海内的潮波以半日潮为主,共有4个半日潮、2个全日潮和1个退化的半日潮旋转潮波系统,且都呈逆时针方向旋转;渤海的半日潮流主要呈顺时针方向旋转,全日潮流呈逆时针方向旋转,黄海的潮流以逆时针旋转为主,东海、朝鲜海峡潮流以顺时针旋转为主;半日分潮流共有13个圆流点,K1(O1)分潮流有10(9)个圆流点,但全日潮流的同潮时线分布较为复杂;太平洋传入东海的4个主要分潮潮能通量分别为118.341GW、19.525GW、5.630GW、3.871GW,一半以上的潮能耗散在南黄海,30%—40%的潮能耗散在东海,其次是北黄海,而渤海最小。     

珠江口磨刀门整治前后水动力数值模拟

磨刀门是珠江的主要泄洪通道之一,径流分配居珠江三角洲八大口门之首。利用磨刀门1977年地形(大规模整治前)和2003年的地形,通过ECOMSED模型模拟了磨刀门海域洪枯季节水动力场,对潮流、余流、潮能通量特性进行了对比,发现整治后磨刀门水动力强度加大,而且流速滩槽分异明显,余流场与落潮流方向一致。20世纪70年代,余流自口门出来后在内海区右偏,现在磨刀门水道余流偏向西部浅滩;潮能通量密度加大,滩槽分布差异明显。     

渤黄东海潮能通量与潮能耗散

利用同化高度计资料和沿岸验潮站资料对潮汐数值模式进行同化,根据同化后的数值模式结果,对渤黄东海中的潮能通量和潮能耗散进行了研究.M2分潮从太平洋进入渤黄东海的潮能为122.499GW,占4个主要分潮进入总量的79%.黄海是半日分潮潮能耗散的主要海区.全日分潮则主要耗散在东海.全日分潮在遇到陆坡的阻挡以后有一部分潮能沿着冲绳海槽向西南传播,并有一部分潮能反射回太平洋,其中O1分潮通过C3断面反射回太平洋的潮能,约占其传入东海潮能的44%.     

基于z坐标海洋模式的全球正压潮波数值模拟研究

The performance of a z-level ocean model, the Modular Ocean Model Version 4(MOM4), is evaluated in terms of simulating the global tide with different horizontal resolutions commonly used by climate models. The performance using various sets of model topography is evaluated. The results show that the optimum filter radius can improve the simulated co-tidal phase and that better topography quality can lead to smaller rootmean square(RMS) error in simulated tides. Sensitivity experiments are conducted to test the impact of spatial resolutions. It is shown that the model results are sensitive to horizontal resolutions. The calculated absolute mean errors of the co-tidal phase show that simulations with horizontal resolutions of 0.5° and 0.25° have about 35.5% higher performance compared that with 1° model resolution. An internal tide drag parameterization is adopted to reduce large system errors in the tidal amplitude. The RMS error of the best tuned 0.25° model compared with the satellite-altimetry-constrained model TPXO7.2 is 8.5 cm for M_2. The tidal energy fluxes of M_2 and K_1 are calculated and their patterns are in good agreement with those from the TPXO7.2. The correlation coefficients of the tidal energy fluxes can be used as an important index to evaluate a model skill.     

海坛海峡二维潮流场数值模拟

海坛海峡为南北狭长型海峡，海峡内潮波属于前进波．本文建立了平面二维浅水波数学方程，利用欧拉-拉格朗日差分方法得到数值解，模型采用随时间变化的动边界技术，成功地模拟了海坛海峡的前进波特征，并根据实测数据进行了验证．同时计算了同潮时线和等振幅线，不同时刻的潮流场和潮流平均流速分布．计算结果表明，北部湾口M2分潮高潮时间比南部湾口早约5～6min，等振幅线范围约为2．12～2．15m．海峡内流速分布呈南北强、中间弱的特点，最大流速1m／s左右．     

围垦对舟山群岛海域潮流结构及潮能分布影响研究

舟山群岛海域潮能丰富,近年来大面积的围垦工程影响了邻近海域的潮流结构与潮能分布特征。基于FVCOM(finite volume coastal ocean model)三维水动力数值模型,选取1984年、2010年、2019年三个代表年份,探讨围垦工程影响下舟山群岛海域潮流结构与潮能分布的时空变化状况。结果显示:1984年至2010年间围垦面积相对不大,且较为分散,主要改变外海进入杭州湾各通道的潮能分配,对能量耗散的影响较小。2010年至2019年间的围垦工程缩窄了潮汐通道,流速增大使得螺头水道及邻近水道的潮能增加,近底流速增大与较强湍流涡旋的产生,使得围垦工程周边海域能量耗散更为集中。     

泰国湾及邻近海域潮汐潮流的数值模拟

本文基于FVCOM(Finite-Volume Coastal Ocean Model)模式,模拟了泰国湾及其周边海域K1、O1、M2和S2四个主要分潮。采用47个验潮站实测调和常数与模拟结果进行比较,所得4个分潮的均方差分别为4.06cm、3.76cm、8.22cm和4.71cm,符合良好。根据计算结果分析了泰国湾及其周边海域的潮汐、潮流的分布特征和潮波的传播特征。数值试验表明,现有的数字水深资料(ETOPO1,ETOPO5,DBDB-V)的准确度不足以合理地模拟泰国湾潮波。     

印度尼西亚海域潮波的数值研究

基于ROMS模式构建了模拟区域为(15.52°S-7.13°N,110.39°~134.15°E)水平分辨率为2′的潮波数值模式,分别模拟了印尼海域M2、S2、K1、O1四个主要分潮。模拟结果与29个卫星高度计交叠点上的调和常数进行比较,符合较好。M2分潮的振幅均方根差为3.4cm,迟角均方根差为5.9°;S2分潮的振幅均方根差为1.7cm,迟角均方根差为6.3°;K1分潮振幅均方根差为1.1cm,迟角均方根差为5.8°;O1分潮振幅均方根差为1.2cm,迟角均方根差为4.4°。M2、S2、K1、O1分潮向量均方根差分别为3.8cm、2.4cm、1.9cm和1.3cm,模拟结果的相对偏差在10%左右。根据计算结果分析了印尼海域的潮汐特征及潮能传播规律,结果显示:爪哇海以外的印尼海域主要为不规则半日潮区;全日潮潮能主要由太平洋传入印尼海域,而半日潮潮能则是从印度洋传入印尼海域。     

台湾海峡及其邻近海域潮汐数值计算

建立二维潮波模式,模拟了台湾海峡及其邻近海域(18-30°N,110-130°E)八个主要分潮(M2、S2、K1、O1、P1、Q1、K2、N2),并利用中国大陆及环台湾岛20多个潮位站的实测资料进行验证,计算结果与实测值吻合良好.此外,给出了八个主要分潮的同潮图,并逐个讨论了潮汐特征.结果显示:⑴台湾海峡中的潮波运动是北部蜕化了的旋转潮波系统和南部的前进潮波系统共同作用的结果.⑵半日分潮南、北两支潮波在台湾海峽中部汇合,而全日分潮则在台湾海峽南部海域汇合后继续朝西南方向传播.⑶半日分潮振幅最高值发生在福建省湄洲湾—兴化湾一带,全日分潮最高值则出现在雷州半岛以东一带近岸海域.⑷N2、K2和O1、P1、Q1分潮的振幅、迟角分布分别同M2与K1分潮的整体分布趋势相似.     

Numerical study of baroclinic tides in Luzon Strait

The spatial and temporal variations of baroclinic tides in the Luzon Strait (LS) are investigated using a three-dimensional tide model driven by four principal constituents, O₁, K₁, M₂ and S₂, individually or together with seasonal mean summer or winter stratifications as the initial field. Barotropic tides propagate predominantly westward from the Pacific Ocean, impinge on two prominent north-south running submarine ridges in LS, and generate strong baroclinic tides propagating into both the South China Sea (SCS) and the Pacific Ocean. Strong baroclinic tides, ∼19 GW for diurnal tides and ∼11 GW for semidiurnal tides, are excited on both the east ridge (70%) and the west ridge (30%). The barotropic to baroclinic energy conversion rate reaches 30% for diurnal tides and ∼20% for semidiurnal tides. Diurnal (O₁ and K₁) and semidiurnal (M₂) baroclinic tides have a comparable depth-integrated energy flux 10–20 kW m⁻¹ emanating from the LS into the SCS and the Pacific basin. The spring-neap averaged, meridionally integrated baroclinic tidal energy flux is ∼7 GW into the SCS and ∼6 GW into the Pacific Ocean, representing one of the strongest baroclinic tidal energy flux regimes in the World Ocean. About 18 GW of baroclinic tidal energy, ∼50% of that generated in the LS, is lost locally, which is more than five times that estimated in the vicinity of the Hawaiian ridge. The strong westward-propagating semidiurnal baroclinic tidal energy flux is likely the energy source for the large-amplitude nonlinear internal waves found in the SCS. The baroclinic tidal energy generation, energy fluxes, and energy dissipation rates in the spring tide are about five times those in the neap tide; while there is no significant seasonal variation of energetics, but the propagation speed of baroclinic tide is about 10% faster in summer than in winter. Within the LS, the average turbulence kinetic energy dissipation rate is O(10⁻⁷) W kg^{− 1} and the turbulence diffusivity is O(10⁻³) m²s⁻¹, a factor of 100 greater than those in the typical open ocean. This strong turbulence mixing induced by the baroclinic tidal energy dissipation exists in the main path of the Kuroshio and is important in mixing the Pacific Ocean, Kuroshio, and the SCS waters.     

Numerical study of M2 internal tide generation and propagation in the Luzon Strait

Based on the z-coordinate ocean model HAMSOM,we introduced the internal-tide viscosity term and applied the model to numerically investigate the M2 internal tide generation and propagation in the Luzon Strait (LS).The results show that (1) in the upper 250 m depth,at the thermocline,the maximum amplitude of the generated internal tides in the LS can reach 40 m;(2) the major internal tides are generated to the northwest of Itbayat Island,the southwest of Batan Island and the northwest of the Babuyan Islands;(3) during the propagation the baroclinic energy scattering and reflection is obvious,which exists under the effect of the specific topography in the South China Sea (SCS);(4) the westward-propagating internal tides are divided into two branches entering the SCS.While passing through 118 E,the major branch is divided into two branches again.The strongest internal tides in the LS are generated to the northwest of Itbayat Island and propagate northeastward to the Pacific.However,to the east of 122 E,most of the internal tides propagate southeastward to the Pacific as a beam.     

浙江近海潮汐潮流的数值模拟

用三维陆架海模式(HAMSOM)对浙江近海的潮汐、潮流进行了数值模拟,并采用网格嵌套和动边界技术对原模式作了改进,以提高计算的精度,改进后的模式在浙江近海的应用中被证明是成功的.沿岸50个潮位站计算与实测值的比较表明,加入动边界以后的小区域细网格计算较之粗网格以及未加动边界以前精度普遍提高,比较的均方差结果为:M₂分潮振幅差4.6cm,相角差7.14°;S₂分潮振幅差5.0cm,相角差5.4°;K₁分潮振幅差2.25cm,相角差5.76°;O₁分潮振幅差1.56cm,相角差5.5°,可见计算与实测符合良好.另外,选取了105个实测潮流点,比较了表层M₂和K₁分潮流调和常数分量Ucosξ,Usinξ,Vcosη,Vsinη的实测值与计算值的偏差,结果表明计算与实测的符合程度较好.在此基础上,给出了各主要分潮的潮位同潮图、潮流同潮图、潮汐性质、潮流性质、潮流椭圆和潮流的运动形式等,发现4个主要分潮M₂,S₂,K₁,O₁在本区内均未出现无潮点;M₂分潮流在29°18'N,122°46'E处有一个圆流点.此外还得到了一些有意义的结论,都与实测情况符合良好,从而对整个浙江沿海区域的潮汐潮流特性有了一个全面认识.     

琼州海峡潮流能资源的数值模拟评估

近年来,我国能源消耗量不断的增长使我们更加重视可再生能源的开发利用,而我国近海拥有复杂的海岸线和广阔的大陆架,其中许多海域蕴藏着丰富的潮流能资源。潮流能资源评估则是其电站站址选择、发电量预测等工程设计的首要工作。结合两个站位的潮流实测数据,本文利用FVCOM海洋环流数值模式较好的模拟了琼州海峡潮波传播状况,分析了该海域潮流能资源水平分布规律和时间变化特征,初步估算了该水道的潮流能的理论蕴藏量,并采用FLUX方法对该水道的技术可开发量进行了评估。结果表明,琼州海峡中心海域功率密度高,两岸资源低;可能最大流速、大潮年平均最大功率密度、小潮年平均功率密度和年平均功率密度等特征值分布基本相似;其丰富区域出现在海峡东口南部海域以及海峡中部海域,其中东口南部海域可能最大流速可达4.6 m/s,表层流大潮年平均最大功率密度为5996 W/m²,小潮平均最大功率密度仅为467 W/m²,年平均功率密度为819 W/m²,代表点超过0.7 m/s的潮流流速年统计时间约为4717 h;海峡潮流能资源理论蕴藏量为189.55MW,利用FLUX、FARM、GC方法得到该水道的潮流能可开发量分别为249GW/yr、20.2GW/yr和263GW/yr。     

珠江河口潮能收支研究

Tidal energy budget in the Zhujiang(Pearl River) Estuary(ZE) is evaluated by employing high-resolution baroclinic regional ocean modeling system(ROMS). The results obtained via applying the least square method on the model elevations are compared against the tidal harmonic constants at 18 tide stations along the ZE and its adjacent coast. The mean absolute errors between the simulation and the observation of M_2, S_2, K_1 and O_1 are 4.6, 2.8, 3.2 and 2.8 cm in amplitudes and 9.8°, 15.0°, 4.6° and 4.6° in phase-lags, respectively. The comparisons between the simulated and observed sea level heights at 11 tide gauge stations also suggest good model performance. The total tidal energy flux incoming the ZE is estimated to be 343.49 MW in the dry season and larger than 336.18 MW in the wet season, which should due to higher mean sea level height and heavier density in the dry season. M_2, K_1, S_2, O_1 and N_2, the top five barotropic tidal energy flux contributors for the ZE,import 242.23(236.79), 52.97(52.08), 24.49(23.96), 16.22(15.91) and 7.10(6.97) MW energy flux into the ZE in dry(wet) season, successively and respectively. The enhanced turbulent mixing induced by eddies around isolated islands and sharp headlands dominated by bottom friction, interaction between tidal currents and sill topography or constricted narrow waterways together account for the five energy dissipation hotspots, which add up to about 38% of the total energy dissipation inside the ZE.