黑潮延伸体海域海平面年际变化及其与海流的关系

利用黑潮延伸体海域海平面异常(SLA)数据和SODA海流资料,分析海平面和海流的年际变化特征,以及两者之间的关系。分析发现黑潮延伸体SLA的第二模态是黑潮大弯曲模态,存在29个月的准两年显著振荡。该海域海平面具有显著的年际变化,且与ENSO和PDO密切相关,2002-2004年的黑潮大弯曲期间,海平面与Nino3指数的相关系数为0.74。海平面年际变化和海流关系密切,黑潮延伸体主轴两侧海平面具有显著的季节和年际变化,急流呈大弯曲路径(1993-1996、2002-2004)时,流轴稳定流速大,流轴影响深,急流主轴南侧海平面较高,达到年际变化的最大值,主轴两侧海面高度梯度大。非弯曲期间,急流主轴南压,海流强度减弱,此期间海平面低,主轴两侧海面高度梯度较小。黑潮延伸体上游区海平面变化受黑潮大弯曲影响更为显著。上下游区的海平面和比容海平面的年际变化较为相似,黑潮延伸体海域海流和比容效应共同调控该区域海平面变化。     

东海黑潮温度锋的三维结构特征分析

结合卫星遥感海表温度、三维再分析温度资料和数值模拟结果,研究了东海黑潮温度锋从海表到底层的三维结构特征.结果 表明:东海黑潮海表温度锋在冬季和春季较强,秋季次之,夏季消失.多年平均的东海黑潮海表温度锋区范围主要在70～700m水深区域,温度锋的中心线与黑潮的流轴大致平行,在济州岛以南的黑潮中段区域有北上的分支.受台湾暖...     

基于WOA13数据的东海黑潮主轴温度锋特征分析

利用WOA13(1955-2012年)月平均数据提取东海黑潮主轴温度锋信息,并结合海表面温度、PN断面温度结构的季节变化特征,研究东海黑潮主轴温度在垂直方向和水平方向的季节变化,探讨黑潮主轴温度锋季节变化特征,为开展黑潮相关研究提供基础。结果表明WOA13数据对东海黑潮主轴温度锋信息的提取具有较好的效果;在PN断面上,冬、春季节的流核结构最为明显;在130~170 m深度上,东海黑潮主轴温度锋具有明显的季节变化特征,并且可以明显看到黑潮大弯曲的存在;温度锋在150 m上下的深度对黑潮路径的表征较为合理。     

利用卫星遥感资料对南海北部陆架海洋表层温度锋的分析

利用7年(1993～1999)月平均的SST卫星遥感资料，分析了南海北部陆架区域海洋表层温度锋在一年中的逐月变化特征，表明南海北部陆架海洋表层温度锋存在明显的季节内变化。结合风场的卫星遥感资料，分析了东北季风对南海北部陆架温度锋的影响，表明东北季风风速的增加有利于温度锋强度的增强。通过对黑潮南海流套入侵较强的1999年2月与流套入侵较弱的1998年2月的SST卫星遥感资料的对比分析，考察了黑潮南海流套的入侵对南海北部陆架温度锋的影响，结果表明黑潮流套的较强入侵能够增加陆架温度锋的强度，对温度锋的走向也会产生一定的影响。     

根据漂流浮标资料对黑潮15m层流路及流轴特征的分析

利用1979-02—2012-03共33a的水帆位于15m层的Argos漂流浮标资料,绘制黑潮流系15m层的多年年平均和月平均流场,运用特征线方法计算得到黑潮流轴,定义黑潮流动路径的边界为流速大小20~30cm/s的过渡性区域。结果显示:黑潮多年年平均流路大致是一个以(13°30′N,142°00′E)为圆心、2 235km为半径的直角弧段,其在吕宋海峡、台湾东北、九州西南及伊豆海岭附近海区发生气旋式弯曲前先进行反气旋式弯曲调整,弯曲处出现的路径开口主要是支流的并入或分支的流出;黑潮流轴整体性偏向黑潮左边界,其中在吕宋岛东北至台湾以东海域最为显著,在本州岛以南海域次之,而在东海段基本居中;黑潮流路上的流速在总体上由南向北呈增大趋势,但并非沿流路持续性逐渐增加,而是呈现出较平直流段的大流速区和弯曲调整流段的低流速区相互交错的状况,其中四国岛以南至伊豆诸岛以西流段的流速为最大。多年月平均流场显示,2月,5月,8月和11月这4个月份是黑潮流路和流轴发生变化的重要转折期,而1月,4月,7月和10月这4个月份则是各季节的代表月份。其中,冬季月份的黑潮流路和流轴最为曲折,向边缘海发生显著入侵;夏季月份的黑潮流路和流轴最为平直,左侧伴随有北向流动;春、秋两季的过渡性特征则比较明显。     

东海黑潮区域性变异的分析

基于中日黑潮合作调查研究期间所获历史和现场观测资料,本文较详细地分析了东海黑潮区域性变异.结果表明:(1)与PN断面及其邻近海域的黑潮中段相比,台湾东北海域的黑潮南段,流轴有较大弯曲,并有明显的季节变化.但该海域黑潮的流速和流幅,以及它们的季节间变幅却比黑潮中段和北段小.(2)东海黑潮南段不仅流轴变化复杂,而且其左侧常有气旋性冷涡出现.而黑潮中、北段接壤区,既是黑潮向东流的转折处,又是黑潮锋面涡旋频繁发生的区域.可认为该两处海域是黑潮影响东海及其邻近海域的关键区段.(3)初步分析指出,地形是导致黑潮区域性变异的主要因素.此外,季风和密度场的变化也起着重要的作用.     

海平面变化对黑潮变异的响应

本文对黑潮影响海区海平面变化进行了分析.发现海平面变化与黑潮变异之间存在着密切关系.每当黑潮大弯曲发生时.海平面上升出现高值。另外还对海平面变化原因做了讨论。     

黑潮在吕宋海峡的形变及动力机制

根据１９９０年以来对吕宋海峡和中国南海（ＳＣＳ）北部的ＷＯＣＥ水文资料和其它海洋调查资料的分析，以及对同一海区的卫星遥测海表温度（ＳＳＴ）的资料处理，推断在吕宋海峡常年存在黑潮路径弯曲，西折进入ＳＣＳ并又流出ＳＣＳ的现象，作者将黑潮的这种变形称为“黑潮流套”。黑潮变形进入ＳＣＳ的位置在冬季位于海峡中部、南部附近，范围较大；在夏季略向北移，较集中于海峡中部，范围较小。作者认为，黑潮流套现象可用位涡守恒理论作定性的解释：当黑潮在吕宋海峡失去西边界支持后，其流轴以西贴近西边界的一部分流体，因具有较大的相对正涡度，会脱离黑潮主体在南海东北部形成反时针旋转或顺时针旋转的环流，而黑潮主体会以顺时针旋转的形式在海峡以西的海域出现。整个黑潮以弯曲、扩展的形式在海峡处产生形变，在海峡东侧出现反气旋涡旋的倾向。吕宋海峡黑潮流套及南海北部的诱生环流之流型，会因黑潮本身以及副热带环流整体的变化而变化，也与海峡的宽度有关。总之，吕宋海峡黑潮流套的形成是由当地特殊的地形条件和地转β效应这些内部机制决定的，它的常年存在有其必然性     

热带气旋过境期间黑潮流轴变化的初步分析

利用卫星高度计资料分析了热带气旋"艾碧"(Abe,9315)、"贝姬"(Becky,9316)、"莫拉克"(Morakot,0309)和"茉莉"(Melor,0319)对吕宋海峡及其附近海域黑潮流轴的影响。研究表明:1)吕宋海峡附近海域黑潮流轴容易受到热带气旋的影响而发生一定的变化。2)在热带气旋的作用下,黑潮流轴因中尺度涡的变异而变化;当吕宋海峡东侧的暖涡西移时,将使黑潮的流轴向西弯曲,有利于黑潮在该处的入侵。     

1981-1983年黑潮弯曲和埃尔尼诺事件的个例分析

在统一考虑黑潮大弯曲和埃尔尼诺事件共同存在的条件下,对水位、海水温度和风场进行了分析.结果发现,1981年黑潮发生大弯曲和1982年出现的埃尔尼诺事件均与相应风场相配合,热带风场变化不仅对黑潮变异有直接影响,而且也是判断这次埃尔尼诺事件爆发的重要依据,从而把1982-1983年的埃尔尼诺与1981-1984年的黑潮弯曲密切联系起来.     

Monitoring of generation and propagation of the Kuroshio small meander using sea level data along the southern coast of Japan

The occurrence of the small meander of the Kuroshio, generated south of Kyushu and propagating eastward, was examined using sea level data collected during 1961–1995 along the south coast of Japan. Intra-annual variation of the sea level was expanded by the frequency domain empirical orthogonal function (FDEOF) modes, and it was found that the second and third modes are useful for monitoring the generation and propagation of the small meander. The third FDEOF for periods of 10–100 days has a phase reversal between Hosojima and Tosa-shimizu with significant amplitude west of Kushimoto, and the amplitude of its time coefficient is large during the non-large-meander (NLM) period and has a significant peak when the small meander exists southeast of Kyushu. The second FDEOF for periods of 20–80 days has a phase reversal between Kushimoto and Uragami, and the amplitude of its time coefficient is large when the small meander propagates to the south of Shikoku. The third FDEOF mode allowed us to conclude that the small meander occurred 42 times from July 1961 to May 1995, most of them (38) occurring during the NLM periods. The second FDEOF mode permits the conclusion that half of the 38 small meanders reached south of Shikoku. Of these, five small meanders influenced transitions of the Kuroshio path from the nearshore NLM path; one caused the offshore NLM path and four brought about the large meander. About one-tenth of the total number of small meanders are related to the formation of the large meander.     

模式参数的不确定性对日本南部黑潮大弯曲路径预报的影响

基于1.5层浅水方程模式,利用条件非线性最优参数扰动(CNOP-P)方法,研究模式参数的不确定性对黑潮大弯曲路径预报的影响。研究表明,单个模式参数误差如侧向摩擦系数误差、界面摩擦系数误差以及在不同季节具有不同约束的风应力大小误差,对黑潮大弯曲路径预报的影响较小,并且对背景流场的选取具有一定的敏感性;所有模式参数误差同时存在时对黑潮大弯曲路径预报具有一定的影响,并且预报结果在9个月左右不能被接受。因此,要提高黑潮大弯曲路径的预报技巧,模式中的参数需要给出更好的估计。     

伊豆海脊两侧顺时针流涡的若干观测证据

本文对方国洪等（１９９５）有关“西北太平洋环流三维结构的计算结果中显示出当黑潮越过伊豆海脊时，由于海脊的阻塞作用，在伊豆海省两侧出现两个顺时针流涡”的论术，提出若干观测和文献的证据，证实这两个流涡是存在的；还对这些流涡的机理作了初步的分析。     

Index and Composites of the Kuroshio Meander South of Japan

Using the merged NOAA National Oceanographic Data Center (NODC)/Japan Oceanographic Data Center (JODC)/Marine Information Research Center (MIRC) historical hydrographic dataset, a new Kuroshio large meander (LM) index is introduced. This index helps to distinguish between the LM events and other types of Kuroshio Current (KC) variability south of Japan. Observations, re-systematized according to the index, provide composite patterns of typical formation and decay of the LM. The patterns reveal a remarkable similarity between individual LMs and support the deterministic rather than the stochastic model of LM evolution on a time-scale of one year. A “trigger” meander (TM) occurs on composite maps six months prior to the LM formation as a 1° latitude southward shift of the KC axis south of Kyushu. When propagating eastward along the coast of Japan, TM gradually increases in area. In principal the emergence of LM takes only one month. East of TM and LM a remarkable onshore shift of the KC is noticed, supplying the coastal region with warm water. Other warm anomalies are found on the warm side of KC next to the propagating TM and in the larger warm eddy area southeast of Kyushu. Different LMs survive for different times and decay in some months after KC “jumps” across the Izu Ridge. Changes of water properties on isopycnals in the interior of LM can be roughly described by two-layer kinematics with an interface at σ_θ = 27 which suggests a strong inflow of deep Kuroshio waters into the LM core during the formation of the latter. This revised version was published online in August 2006 with corrections to the Cover Date.     

Identifying the sensitive areas in targeted observation for pre-dicting the Kuroshio large meander path in a regional ocean model

With the Regional Ocean Modeling System(ROMS), this paper investigates the sensitive areas in targeted observation for predicting the Kuroshio large meander(LM) path using the conditional nonlinear optimal perturbation approach. To identify the sensitive areas, the optimal initial errors(OIEs) featuring the largest nonlinear evolution in the LM prediction are first calculated; the resulting OIEs are localized mainly in the upper2 500 m over the LM upstream region, and their spatial structure has...     

The behavior and the role of the anti-cyclonic eddy in the Kuroshio large meander development

The processes underlying the development of the Kuroshio large meanders that occurred in 1986 and 1989 are investigated using a satellite SST data set and hydrographic data. In both processes visible on the satellite SST images, a round-shaped, lower SST region with a diameter of about 200 km is found to the east of the Kuroshio small “trigger” meander (Solomon, 1978) until the region became extinguished near theEnshu Nada. The lower SST region can be interpreted as an anti cyclonic eddy, mainly because of the existence of a warm water mass in the subsurface layer of this region. The warm water mass is characterized by a constant temperature of 18–19°C, the maximum thickness of which is about 400 m. The satellite images show that the eddy is closely related to the Kuroshio path transforming into a shape like the letter “S”. This means that the eddy plays an important role in the development of the Kuroshio large meander since this, too, tends to follow an “S”-shaped path. Added to this, the subsurface layer structure of the eddy is similar to that of the warm water mass offShikoku. This similarity, together with the eddy behavior visible on the satellite SST images, implies that the examined eddy corresponds to the warm water mass offShikoku. In other words, the warm water mass offShikoku can be advected near to theEnshu Nada when the Kuroshio large meander occurs.     

Variations of the Kuroshio Axis South of Kyushu in Relation to the Large Meander of the Kuroshio

The characteristics of the Kuroshio axis south of Kyushu, which meanders almost sinusoidally, are clarified in relation to the large meander of the Kuroshio by analyzing water temperature data during 1961–95 and sea level during 1984–95. The shape of the Kuroshio axis south of Kyushu is classified into three categories of small, medium, and large amplitude of meander. The small amplitude category occupies more than a half of the large-meander (LM) period, while the medium amplitude category takes up more than a half of the non-large-meander (NLM) period. Therefore, the amplitude and, in turn, the curvature of the Kuroshio axis is smaller on average during the LM period than the NLM period. The mean Kuroshio axis during the LM period is located farther north at every longitude south of Kyushu than during the NLM period, with a slight difference west of the Tokara Islands and a large difference to the east. A northward shift of the Kuroshio axis in particular east of the Tokara Islands induces small amplitude and curvature of the meandering shape during the LM period. During the NLM period, the meandering shape and position south of Kyushu change little with Kuroshio volume transport. In the LM formation stage, the variation of the Kuroshio axis is small west of the Tokara Islands but large to the east due to a small meander of the Kuroshio. In the LM decay stage, the Kuroshio meanders greatly south of Kyushu and is located stably near the coast southeast of Kyushu. This revised version was published online in July 2006 with corrections to the Cover Date.     

黑潮大弯曲时期日本鲭幼体输运数值模拟研究

日本鲭是一种重要的经济鱼类,广泛分布于西北太平洋沿岸海域,其资源和补充很容易受到环境因素的影响,尤其是在鱼类的早期生活阶段,即卵和幼体阶段。本文建立了一个基于个体的模型（Individual-Based Model,IBM）用以研究典型大弯曲期间黑潮主流、周围环流以及中尺度涡对日本鲭早期生命活动的影响。数值模拟及研究结果表明：（1）在深度分布方面,大部分个体（鱼卵或仔稚鱼）位于75 m以浅水层中,只有少部分被垂直湍流带入更深的水域。（2）在产卵场和育幼场之间的连通性方面,3-5月来自主要产卵场的个体随黑潮主流进入黑潮延伸区的渔场;6月份,主要产卵场中的个体受到黑潮大弯曲东侧的小型冷涡的影响,该冷涡阻止了其进入黑潮延伸区的渔场,并留在纪伊半岛和伊豆群岛的沿海水域。在昼夜垂直迁移（Diel Vertical Migration,DVM）这一输运方式的影响下,停留在四国岛和纪伊半岛附近的个体数量增加,处于DVM输运方式下的个体受冷涡的影响更大,增加了在海洋表面漂流的时间,无法跟随黑潮主流输送到更远的育幼场。（3）在输送距离方面,90%以内的个体进行短距离到中距离输运,在DVM输运方式下,长距...     

Bifurcation current along the southwest coast of the Kii Peninsula

Along the southwest coast of the Kii Peninsula, a bifurcation current is regularly observed. By using ADCP data taken on board the R/V Wakayama of the Wakayama Prefectural Fisheries Experimental Station, characteristics of this bifurcation current are analyzed. The occurrence frequency of the bifurcation current reaches about 70% in the period from 1988 to 1996. The bifurcation point appears to be changeable and occurs almost evenly between Cape Ichie and Cape Shionomisaki. The current divergence in the alongshore direction was also investigated. Positive divergence values dominated in the whole analyzed area, and an onshore current appears to be dominant along the southwest coast of the Kii Peninsula, except in 1990 when the Kuroshio flowed in a large meandering path.