Circulation and currents in the southwestern East/Japan Sea: Overview and review

A review is made of circulation and currents in the southwestern East/Japan Sea (the Ulleung Basin), and the Korea/Tsushima Strait which is a unique conduit for surface inflow into the Ulleung Basin. The review particularly concentrates on describing some preliminary results from recent extensive measurements made after 1996. Mean flow patterns are different in the upstream and downstream regions of the Korea/Tsushima Strait. A high velocity core occurs in the mid-section in the upstream region, and splits into two cores hugging the coasts of Korea and Japan, the downstream region, after passing around Tsushima Island located in the middle of the strait. Four-year mean transport into the East/Japan Sea through the Korea/Tsushima Strait based on submarine cable data calibrated by direct observations is 2.4 Sv (1 Sv = 10⁶ m³ s⁻¹). A wide range of variability occurs for the subtidal transport variation from subinertial (2–10 days) to interannual scales. While the subinertial variability is shown to arise from the atmospheric pressure disturbances, the longer period variation has been poorly understood.Mean upper circulation of the Ulleung Basin is characterized by the northward flowing East Korean Warm Current along the east coast of Korea and its meander eastward after the separation from the coast, the Offshore Branch along the coast of Japan, and the anticyclonic Ulleung Warm Eddy that forms from a meander of the East Korean Warm Current. Continuous acoustic travel-time measurements between June 1999 and June 2001 suggest five quasi-stable upper circulation patterns that persist for about 3–5 months with transitions between successive patterns occurring in a few months or days. Disappearance of the East Korean Warm Current is triggered by merging the Dok Cold Eddy, originating from the pinching-off of the meander trough, with the coastal cold water carried Southward by the North Korean Cold Current. The Ulleung Warm Eddy persisted for about 20 months in the middle of the Ulleung Basin with changes in its position and spatial scale associated with strengthening and weakening of the transport through the Korea/Tsushima Strait. The variability of upper circulation is partly related to the transport variation through the Korea/Tsushima Strait. Movements of the coastal cold water and the instability of the polar front also appear to be important factors affecting the variability.Deep circulation in the Ulleung Basin is primarily cyclonic and commonly consists of one or more cyclonic cells, and an anticyclonic cell centered near Ulleung Island. The cyclonic circulation is conjectured to be driven by a net inflow through the Ulleung Interplain Gap, which serves as a conduit for the exchange of deep waters between the Japan Basin in the northern East Sea and the Ulleung Basin. Deep currents are characterized by a short correlation scale and the predominance of mesoscale variability with periods of 20–40 days. Seasonality of deep currents is indistinct, and the coupling of upper and deep circulation has not been clarified yet.     

台湾东北海域冷水块的特征

根据海洋调查历史资料 ,对台湾东北海域冷水块的时空分布、结构、特点进行分析 ,主要结果如下 :(1 )首次利用卫星跟踪漂流浮标的轨迹 ,佐证冬季该冷水块的存在。 (2 )鉴于该冷水的重要性 ,建议对它给予称谓 ,暂定名为“彭花棉”冷水块。 (3 )该冷水块是黑潮次表层水涌升的结果 ,是黑潮对我国近海海洋环境影响的典型实例之一。 (4)该冷水块具有低温、高盐、高密、低氧、高磷、高硅和高氮等特性     

台湾海峡1997年8月至1999年8月份海水光学衰减系数的分布特征

利用1997－1999年间8月份台湾海峡的实测资料，分析了海水光学衰减系数的垂直分布类型、水平分布特征。结果表明，台湾海峡海水光学衰减系数的垂直分布类型主要分为5种，大部分随深度而递增；光学衰减系数等值线基本与岸线平行，水平梯度自北向南、自近岸向外海递减，近岸等值线密集，而外海稀疏；影响台湾海峡光学衰减系数的主要因素是县浮物质（主要含浮游生物）和海流运动。     

台湾海峡及其邻近海域中华哲水蚤的分布和繁殖

中华哲水蚤(Calanus sinicus Brodsky)是我国近海的优势桡足类。它的数量大，分布广。特别在冬、春季，在我国近海浮游动物中，占有相当大的比例；同时它的个体也较大，是滤食性种类。因其在海洋生态系统的物质循环和能量流动中，起着相当的作用，所以被国家自然科学基金重大项目-“东、黄海生态系统动力学与生物资源可持续利用”课题定为浮游动物的关键种之一。 作者根据以往历史资料(方金钏，1979；朱长寿，1997；朱长寿等，1991、1999；林玉辉等，1988；林元烧等，1984；李少菁，1963；陈清潮，1964；福建省海岸带和海凃综合调查领导小组，1990；福建海洋研究所，1988；Tan，1970)和多年来的研究结果(黄加祺等，1984，1986a、b、c，1989，1991a、b，1997a、b)，对中华哲水蚤在不同水域的分布，与温、盐度关系及繁殖进行了探讨，并提出见解，为本项目子课题提供了历史资料。     

台湾海峡中、北部及邻近海域夏季浮游动物总生物量的分布特点

台湾海峡中、北部夏季浮游动物（非胶质）总生物量较丰富，1983年夏季的总生物量高于其他季节，1987年7、8月和1988年7月则高于1983年同期的生物量，这3a的高生物量分布区，一般都连片出现在上升流锋面区，显然和上升流的出现有密切关系。构成高生物量的优势种以外海广高盐种为主，生物量和高生物量区的分布态势都存在年际变化，这可能和不同性质水系的消长，相互推移及被囊动物的摄食竞争有关。     

环台湾岛海域半日潮波特征的三维模拟

用1997版POM海洋模式,首次应用于环台湾岛海域的潮波数值研究.得到该海域的半日潮波主要为23°N以南西太平洋传来的胁振潮.影响台湾海峡的半日潮波分别由海峡南北口传入的两支潮波,且北支强于南支.福建沿岸湄州湾-兴化湾为最强潮区,其M₂分潮最大振幅可达240cm.最强潮流区位于澎湖水道,M₂分潮最大潮流达196cm/s.环台湾岛海域潮波潮流水平结构上除海峡北部原有一个圆流点外,还发现另外存在4个新的圆流点.潮流垂直结构上主要为右偏,接近底层处为左偏.     

厦门港湾和闽南-台湾浅滩海域鱼类感染吸虫的调查研究

本文根据1980～1986年厦门港湾和闽南-台湾浅滩海域的调查资料,报道了该海区鱼类感染复殖吸虫的概况。在我们检查的106种鱼类中,从其中54种的消化道和1种的体腔中发现复殖吸虫标本1269个,感染率为28.24%。本海区鱼类生态习性虽有差异,其感染率和阳性鱼的感染度可能有明显差异,但从总体上看,不同生态类群鱼类的吸虫密度分布甚为均匀。     

弯睾鲫吸虫[Carassotrema flecterotestis(Zhukov,1971)comb.nov.]及其毛蚴发育观察

本文对取自台湾海峡棱鮻 (Lizacarinatus)消化道的弯睾软穴吸虫 (HapalotremaflecterotestisZhukov, 1971)进行重新描述,并对其毛蚴的体外发育进行观察.根据Yamaguti(1971)区分单孔科 (Haploporidae)和叉盘科 (Waretrematidae)的标准,同意李敏敏(1984)将其从单孔科移出并入叉盘科.在与叉盘科已知属比较后,我们发现该吸虫除睾丸形状外,其他主要特征与鲫吸虫属 (CarassotremaPark, 1938)的相似.因此,我们拟将其作为后者的同物异名,并将该吸虫重新命名为弯睾鲫吸虫 [Caras sotremaflecterotestis(Zhukov, 1971)comb. nov. ].实验结果表明:在室温 7~24℃(均值为 15. 3℃)条件下,其虫卵从单个卵细胞到毛蚴孵出共需 12d.     

A study on benthic community structure in west of the Taiwan Strait and near the Taiwan Shoals

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Freshening of the Intermediate Waters in the Northern South China Sea over the PastSix Decades

The properties of salinity in the South China Sea (SCS), a significant marginal sea connecting the Pacific andIndian Oceans, are greatly influenced by the transport of fresh water flux between the two oceans. However, the long-termchanges in the intermediate water in the SCS have not been thoroughly studied due to limited data, particularly in relationto its thermodynamic variations. This study utilized reanalysis data products to identify a 60-year trend of freshening in theintermediate waters of the northern South China Sea (NSCS), accompanied by an expansion of low-salinity water. Thestudy also constructed salinity budget terms, including advection and entrainment processes, and conducted an analysis ofthe salinity budget to understand the impacts of external and internal dynamic processes on the freshening trend of theintermediate water in the NSCS. The analysis revealed that the freshening in the northwest Pacific Ocean and theintensification of intrusion through the Luzon Strait at intermediate levels are the primary drivers of the salinity changes inthe NSCS. Additionally, a weakened trend in the intensity of vertical entrainment also contributes to the freshening in theNSCS. This study offers new insights into the understanding of regional deep sea changes in response to variations in boththermodynamics and oceanic dynamic processes.