渤、黄海风生流场季节循环时空模态与变异

根据1978—2015年渤、黄海沿岸观测风应力场与二维非线性垂直平均风生流模式，以及旋转经验正交函数（REOF）、调和分析等方法，研究了渤、黄海月平均风生流速度势、流函数场季节循环时空模态与年际变异.渤、黄海月平均风生流速度势、流函数场主要有两种时空模态，季节周期分量是时空模态的主要分量.由于风应力场季节循环变异，渤海流函数场季节时空循环变异程度大于速度势场，速度势、流函数场第二模态是季节变异的主要分量，黄海速度势场季节时空循环变异程度大于流函数场，速度势场第二模态是季节变异的主要分量.由于月平均风应力场强度年际变化显著线性减弱，渤、黄海季节平均风生流场强度年际变化也显著减弱.渤、黄海暖流与冷水团季节生消是风生流水平环流与垂直对流对冷 暖水体输送与汇集共同作用的结果，渤、黄海春、夏季辐合上升环流延缓及减弱了浅层暖水向深层传播，是春、夏季冷水团与温跃层形成的重要动力因素，因此，速度势是研究渤、黄海风生流场十分重要的因素.冬季渤海中部、黄海东部反气旋型及辐散下沉环流与黄海中部气旋型环流、辐合上升环流是黄海暖流季节转换与强度的主要动力控制因素，夏季黄海东部气旋型环流、辐合上升环流与黄海中部反气旋型环流、辐散下沉环流是黄海冷水团季节转换与强度的主要动力控制因素.     

渤、黄海冬、夏季节风生流场年际变化时空模态与环流变异

根据1975—2017年冬、夏季节渤、黄海沿岸25个气象站风观测资料,采用二维非线性垂直平均风生流模式、旋转经验正交函数(REOF)等方法,研究了渤、黄海冬、夏季节平均风生流速度势与流函数场年际变化时空模态与环流变异.由于冬、夏季节渤、黄海风应力场强度年际变化显著线性减弱趋势,冬季渤、黄海平均速度势与流函数强度年际变化线性减弱速率大于夏季,黄海冬、夏季平均速度势与流函数强度年际变化线性减弱速率大于渤海.渤、黄海冬、夏季节平均风生流速度势与流函数场年际变化主要有两种时空模态,冬季渤海垂直环流显著线性减弱以及水平环流准平衡态年际变化是主要分量,冬季黄海垂直与水平环流准平衡态年际变化是主要分量.夏季渤海垂直环流显著线性减弱以及水平环流准平衡态年际变化是主要分量,夏季黄海大部分海域垂直环流显著线性减弱与局部垂直环流显著线性增强年际变化是主要分量,夏季黄海水平环流形态此消彼长显著线性增强及减弱年际变化是主要分量.冬季黄海暖流暖水向南黄海西侧以及向渤海中部输送过程是在3～4个环流之间传递形成,并非由单一环流输送形成.冬季渤海中部辐散下沉反气旋环流与黄海中部至渤海海峡的气旋环流、黄海东部辐散下沉反气旋环流是冬季黄海暖流强度与范围的控制环流,夏季渤海中部辐散下沉反气旋环流与黄海中部辐合上升气旋型环流是夏季渤、黄海冷水团强度与范围的控制环流,冬、夏季节渤、黄海控制环流年际变化形态的变换形成冬季黄海暖流与夏季渤、黄海冷水团暖年或冷年的年际变化.     

渤海冬季风生环流的年际变化特征及机制分析

为探究渤海冬季风生环流的年际变化及机制,在近35年NCEP CFSR大气强迫下,利用ROMS海洋模式对渤海冬季流场进行了高分辨率的数值模拟。模式结果基本重现了已知的渤海冬季风生环流的主要特征。渤海冬季深度平均流场的EOF结果显示:首先,第一模态中风向的改变引起了一个环绕整个渤海的环流结构变化;其次,第二模态反映了渤海冬季环流存在的线性增强趋势与风场增强有关,尤其在1995年之后。从模式结果中发现,风场对渤海冬季流场存在的年际变化起到重要作用,风向的偏转对环流年际特征的影响强于风速变化。     

2000年夏末和翌年初冬渤海水文特征

利用2000年夏季和2001年冬季渤海两次CTD资料,系统分析了渤海冬、夏季温盐密度的分布特征,并揭示了渤海现有的水文特征与以往研究结果相比存在一些新现象,表现在:夏季在渤海海峡、辽东湾口和渤海湾口中部中、下层存在3个低温中心,在渤海中部则出现1个上下均匀一致的高温中心;冬季等温线以渤海海峡暖中心向西和向北两个方向伸入渤海,而从秦皇岛外海有一冷水舌向东南方向伸展,在渤海中部海域形成"马鞍状"等温线结构.冬、夏季渤海盐度比以往有显著升高,并明显高于北黄海西部,盐度分布势态表现为渤海湾高盐,渤海海峡低盐特征.密度分布表明:夏季渤海的密度流较强,并在中部可能存在多个密度流涡环;冬季渤海"马鞍状"温盐结构反映其环流结构要比以往研究结果复杂得多,黄海暖流(余脉)在渤海存在分支现象.利用模式对其进行密度流的诊断模拟,结果和实测温盐场符合较好.     

Numerical study on the summer circulation of the upper South China Sea and its establishment

A coupled single-layer/two-layer model is employed to study the South China Sea (SCS) upper circulation and its response before and after the onset of summer monsoon. It is found that, in summer, due to the β effect and the first baroclinic mode of the wind-driven current, a northward western boundary jet current is formed along the Indo-China Peninsula coast, and it leaves the coast at about 13° N and diffuses towards northeast; next to the Indo-China Peninsula, a large anticyclonic     

北部湾三维风生流及密度流模拟

将Casulli差分格式引入三维物理海洋模型计算，模拟了北部湾风生流及密度流。模拟结果表明，夏季西南季风在北部湾导致一个顺时针环流，夏季海水密度梯度导致一个逆时针方向的环流，密度流明显强于风生流；冬季东北寒潮导致一个逆时针环流。模拟结果不支持北部湾夏季为一顺时针环流、冬季为逆时针环流的传统结论，而支持终年为逆时针环流的观点。     

A numerical study of the seasonal circulation in the Seto Inland Sea,Japan

The seasonal variation of water circulation in the Seto Inland Sea is investigated using a high resolution, three-dimensional numerical ocean model. The model results are assessed by comparison with long-term mean surface current and hydrographic data. The simulated model results are consistent with observations, showing a distinct summer and winter circulation patterns. In summer the sea water is highly stratified in basin regions, while it is well mixed near the straits due to strong tidal mixing there. During this period, a cold dome is formed in several basins, setting up stable cyclonic eddies. The cyclonic circulation associated with the cold dome develops from May and disappears in autumn when the surface cooling starts. The experiment without freshwater input shows that a basin-scale estuarine circulation coexists with cyclonic eddy in summer. The former becomes dominant in autumn circulation after the cold dome disappears. In winter the water is vertically well mixed, and the winter winds play a significant role in the circulation. The northwesterly winds induce upwind (downwind) currents over the deep (shallow) water, forming a “double-gyre pattern” in the Suo-Nada, two cyclonic eddies in Hiuchi-Nada, and anticyclonic circulation in Harima-Nada in vertically averaged current fields.     

基于FVCOM的渤海冬季三维风生环流数值模拟

利用FVCOM海洋模型以及MM5气象模式预报风场,对渤海冬季三维风生环流进行了数值模拟,结果显示:渤海风生环流具有显著的三维结构,表层基本沿风向运动,量值在5~10 cm/s,海峡处流速可达15 cm/s,底层有明显的补偿流,量值<3 cm/s;深度平均流环流状态明显,渤海海峡海流北进南出,渤海中部以及辽东湾为一顺时针环流,渤海湾以及莱州湾基本呈逆时针环流。文章通过对比实验,进一步讨论了海面风应力以及海底地形对渤海环流的不同影响,得出:在渤海中部风应力的切变涡度是形成顺指针流型的主要驱动力;除渤海中部以外,渤海冬季流型受地形作用的影响要大于海面风场的切变涡度。     

东中国海拉格朗日环流数值模拟Ⅱ.环流模拟

依据自适应数值模型，模拟了东中国海冬、夏季三维斜压Lagrange环流。模拟发现：台湾暖流的上层水来自台湾海峡入流和台湾东北黑潮的表层水；50m以下的深底层水主要由台湾东北黑潮的次表层水入侵陆架生成。冬季对马暖流外海一侧主要由黑潮水构成，而其近陆一侧由台湾暖流和陆架混合水构成，西朝鲜沿岸流在济州海峡汇入对马暖流；夏季它还包含转向后的长江冲淡水。冬季黄海暖流并非对马暖流的直接分支，黄海暖流水是对马暖流水和陆架水混合而成，这与传统观点相悖，而与中韩黄海水循环动力学合作调查结果一致。黄海暖流东西两侧分别为2支向南流动的滑岸流。夏季黄海环流构成基本封闭的逆时针环流。冬季渤海环流主要有一逆时针大环流，但辽东湾的环流是顺时针向的。渤海环流冬强夏弱，水流在渤海海峡北进南出。     

夏季南海上层环流动力机制的数值研究

通过利用一个分区性的正压-斜压衔接模式来探讨夏季南海的上层环流特征及其动力机制,结果表明:夏季期间,由于风生环流的不稳定性促使在东沙群岛附近的气旋涡的强度及位置发生变化,并间接导致黑潮侵入南海北部的程度变化以及气旋涡南侧的反气旋式环流、西沙群岛西南侧的气旋涡的强度和范围出现波动现象;在南海南部的北向西边界流由于离岸的西南季风所驱动在中南半岛中部沿岸脱离岸线往东北方向的流动,导致沿岸的水体大量流失而在沿岸形成一支南向补偿流并在西沙群岛西南侧诱生一气旋涡,而上述的离岸西边界流则作顺时针方向流动,从而在南海南部形成反气旋式大环流;在南沙海槽附近出现的局地气旋涡和万安滩附近的气旋涡分别受β效应、底形效应的作用而形成.     

Three-D numerical simulation of wind-driven current and density current in the Beibu Gulf

The Beibu Gulf circulation plays an imPOrtant role in the long--term water rnass transportinside the gulf. It is also closely related to the Guangxi untal water mass transport and self-purification. Hence, it is of practical imPOrtance to study the circulation in the gUlf. The cir-culation in the gUlf is very comlicated, and is rnainly gOverned by wind, water density gradi-ent, the current outside the gulf and the bathpoetry. In spring, a cold water rnass generatesln the center of the gulf…     

El Ni?o 事件期间南海环流的异常特征

基于CORA再分析资料对南海环流的季节特征和其受ElNio事件的响应进行了分析。结果表明,冬季整个南海海区表现为一个大的气旋式环流,夏季南海北部是气旋式环流,南部是一个反气旋式环流。通过对南海海区异常流场进行MV-EOF分解,分析其前两个模态,其空间型主要体现了南海环流冬季和夏季的特征,对应的时间系数与Nio3.4_NDJ指数有很好的相关性。通过分析南海环流在1986—2008年间ElNio年份的异常流场和异常流函数场,证明了MV-EOF分解后得到的联合时间系数所反映各阶段南海环流的季节特征与ElNio事件有相关性,即在8月[0],南海南部异常流函数场表现为反气旋式环流,北部为气旋式环流,南海夏季环流被增强,且ElNio事件时间尺度越长,北部的气旋式异常流场的影响范围就越大;在12月[0],南海除了东南部外,其余整个海区异常流函数场主要表现为反气旋式环流,冬季环流被减弱;在8月[+1],南海夏季流场强度都被削弱了。     

Wind-driven circulation in the Japan Sea and its influence on the branching of the Tsushima Current

Seasonal variation in the wind-driven circulation in the Japan Sea is studied with reference to the branching of the Tsushima Current using a two-layer model with simplified bottom and coastal topography. The system is driven by wind stress, an inflow corresponding to the Tsushima Current and by the two outflows corresponding to the Tsugaru and Soya Currents.In the first phase, an annual mean wind stress is imposed and a quasi-stationary state is obtained. In the next phase, a seasonally varying wind stress is imposed. Seasonal variation in the wind stress plays an important role in the branching system of the Tsushima Current. In winter, an intensified western boundary current with a prominent inner circulation is formed as a result of a strong wind stress of winter monsoon with negative wind stress curl. In spring to summer, the western boundary current is weak, but the topographic branch along the Japanese coast is intensified. The weak western boundary current is caused by weak wind stress with positive wind stress curl, which induces cyclonic Sverdrup flow in the Japan Sea and causes its western boundary current to flow in the opposite direction to the prescribed northward boundary inflow current. The topographic branch is strongest in late spring and moves offshore in summer, in agreement with the central branch denoted by Kawabe (1982b). Some of the observational features of the Tsushima Current are successfully simulated.     

广西主要港湾余流特征及其对物质输运的影响

广西5个主要海湾各有自己的环流特征：铁山湾存在一个反气旋涡，廉州湾存在一个海湾尺度的气旋环流，钦州湾青菜头南端存在一个气旋式环流，防城湾口有一个气旋环流。珍珠湾余流，在深水航道内自湾内指向湾外。冬季，受北风影响，各湾从湾内流向湾外的余流分量加强。由于反气旋或气旋环流存在，形成和环流相应的泥沙输运。     

南海等密度面环流季节变化的数值模拟研究

In this study, we develop a variable-grid global ocean general circulation model(OGCM) with a fine grid(1/6)°covering the area from 20°S–50°N and from 99°–150°E, and use the model to investigate the isopycnal surface circulation in the South China Sea(SCS). The simulated results show four layer structures in vertical: the surface and subsurface circulation of the SCS are characterized by the monsoon driven circulation, with basin-scaled cyclonic gyre in winter and anti-cyclonic gyre in summer. The intermediate layer circulation is opposite to the upper layer, showing anti-cyclonic gyre in winter but cyclonic gyre in summer. The circulation in the deep layer is much weaker in spring and summer, with the maximum velocity speed below 0.6 cm/s. In fall and winter, the SCS deep layer circulation shows strong east boundary current along the west coast of Philippine with the velocity speed at 1.5 m/s, which flows southward in fall and northward in winter. The results have also revealed a fourlayer vertical structure of water exchange through the Luzon Strait. The dynamics of the intermediate and deep circulation are attributed to the monsoon driving and the Luzon Strait transport forcing.     

北部湾环流和沉积物输运的数值模拟

研究环流和沉积物输运对北部湾的环境保护和资源开发十分重要。本文使用区域海洋模型（ROMS）,研究了北部湾海域的季节环流、沉积物输运以及长期的地形演变过程。展示了湾内冬季和夏季都存在逆时针环流,冬季的风生环流比夏季强的特征。悬沙浓度较大值主要分布在琼州海峡、海南岛西侧海域,以及越南沿岸、雷州半岛沿岸等近岸地区。沉积物在琼州海峡附近表现为在冬季由东向西输运,夏季则相反;在琼州海峡西口处,沉积物全年以西向输运为主。结果显示,北部湾内沉积物输运主要由潮流引起的再悬浮控制。侵蚀和淤积的分布模式为：（1）湾内大部分区域侵蚀淤积不明显,（2）琼州海峡两侧口门附近淤积比较明显,（3）琼州海峡内深槽侵蚀严重,（4）海南岛西侧海域存在侵蚀和淤积交替发生区域。     

南海海洋环流季节变化的数值模拟研究

基于POM(Princeton Ocean Model)海洋模式,对南海不同深度环流的季节性变化进行了数值模拟研究。模拟结果表明:南海表层和上层环流受季风影响,在夏季西南季风驱动下,南海表层环流在南部呈现强反气旋式结构,在南海北部则是一个弱的气旋环流;在冬季东北季风驱动下,南海表层环流结构呈气旋式,并且明显加强了沿越南沿岸向南流动的西边界流;春季和秋季为南海季风的转换期,其对应的环流特征也处于冬季环流与夏季环流的过渡流型,流速与冬季和夏季相比较弱。南海200m层环流的季节变化与表层相似。在500与1 000m层,则出现许多处中尺度漩涡,流场也变得较为紊乱。     

南海的季节环流─TOPEX/POSEIDON卫星测高应用研究

应用1992～1996年的TOPEX/POSEIDON卫星高度计遥感资料,研究了冬、夏季风强盛期多年平均的南海上层环流结构。研究结果表明,南海上层流结构呈明显的季节变化,在很大程度上受该海区冬、夏交替的季风支配。冬季总环流呈气旋型,并发育有两个次海盆尺度气旋型环流;夏季总环流大致呈反气旋型、但在南海东部18°N以南海域未见明显流系发育。研究还表明,南海环流的西向强化趋势明显,无论冬、夏在中南半岛沿岸和巽他陆架外缘均存在急流,其流向冬、夏相反,是南海上层环流中最强劲的一支。鉴于该海流的动力特征与海洋动力学中定义的漂流不同,有相当大的地转成分,建议称为“南海季风急流(South China Sea MonsoonJet)”.冬季南下的季风急流在南海南部受巽他陆架阻挡折向东北,沿加里曼丹岛和巴拉望岛外海有较强东北向流发育。夏季北上的季风急流在海南岛东南分为两支:北支沿陆架北上,似为传统意义上的南海暖流;南支沿18°N向东横穿南海后折向东北;二者之间(陆架坡折附近)为弱流区。两分支在汕头外海汇合后,南海暖流流速增强。就多年平均而言,黑潮只在冬季侵入南海东北部,并在南海北部诱生一个次海盆尺度的气旋型环流,这时南海暖流只出现在汕头以东海域.夏季南海北部完全受东北向流控制,未见黑潮入侵迹象.用卫星跟踪海面漂流浮标观测进行的对比验证表明,以上遥感分析结果与海上观测一致。     

Model study of the upper circulation in the Sulu Sea and its relation to the South China Sea circulation

According to the satellite remote sensing monthly mean sea surface temperature data from 1998 to 2002, it is shown that, the Sulu Sea is dominated by a cold eddy both in summer and winter. A coupled single-layer/two-layer model is employed here to study the summery and wintry characteristics and dynamic mechanism of the upper circulation in the Sulu Sea. According to the numerical experiments, it is found that, due to the local monsoon stress cud, the upper circulation in the Sulu Sea is dominated by a weak anticyclonic eddy in summer and a strong cyclonic eddy in winter. Once there is a large outflow via the Sibutu Passage flowing out of the Sulu Sea in summer, the upper circulation in the Sulu Sea may be dominated by a cyclonic eddy instead of the normal anti- cyclonic one. Moreover, in summer, the water exchange between the Sulu Sea and South China Sea via the Mindoro and Balabac Straits might have some effect on the separation position and strength of the northward western boundary current next to the Indo - China Peninsula in the southern South China Sea.     

南海上层环流季节变化的诊断计算

通过一个全球的二维诊断模型,采用Levitus温盐资料和COADS风应力资料,并结合动力计算来研究南海上层环流的季节变化。计算结果与其它模式结果和观测结果非常相似。南海北部(南部)全年存在一气旋式(反气旋式)环流。在冬季气旋式环流几乎占据了整个南海,夏季则以反气旋式环流为主。泰国湾的环流在冬季(夏季)是气旋式的(反气旋的)。南海的西边界流有明显的季节变化,其在冬季从卡里马塔海峡流出南海,夏季部分西边界流从台湾海峡流出南海。越南离岸流在春季就开始出现,其位置比夏季的越南离岸流的位置偏北。