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1.
Yoshihiko Sekine 《Progress in Oceanography》1986,17(3-4)
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. 相似文献
2.
By using Acoustic Doppler Current Profiler (ADCP) measurements with the four round-trips method to remove diurnal/semidiurnal
tidal currents, the detailed current structure and volume transport of the Tsushima Warm Current (TWC) along the northwestern
Japanese coast in the northeastern Japan Sea were examined in the period September–October 2000. The volume transport of the
First Branch of the TWC (FBTWC) east of the Noto Peninsula was estimated as approximately 1.0 Sv (106 m3/s), and the FBTWC continued to flow along the Honshu Island to the south of the Oga Peninsula. To the north of the Oga Peninsula,
the Second Branch of Tsushima Warm Current and the eastward current established by the subarctic front were recombined with
the FBTWC and the total volume transport increased to 1.9 Sv. The water properties at each ADCP line strongly suggested that
most of the upper portion of the TWC with high temperature and low salinity flowed out to the North Pacific as the Tsugaru
Warm Current. In the north of the Tsugaru Strait, the volume transport of the northward current was observed to be as almost
1 Sv. However, the component of the TWC water was small (approximately 0.3 Sv). 相似文献
3.
本文全面地分析了此段海流的流路与流速结构，首次提出研究海域近底层的环流示意图。指出在夏季，韩国南岸和日本九州北岸均存在着一支南下的逆流，九州西岸出现两种或多种形式的流路。对马暖流在源地流速很弱，流向不稳定，流路时隐时显不明显，只有离开源地后才逐渐显示出一支海流轮廓；强流区在朝鲜海峡附近。该海流可明显地划分为三段。流速夏强冬弱，夏季流幅宽约８０ｋｍ。 相似文献
4.
黄、东海水母质点追踪影响因素分析 总被引：5，自引：3，他引：2
基于数值模型采用质点追踪的方法对大型水母的运移规律及其聚集的影响因素进行了研究。本文共设置6个质点释放区,分别从3、4、5月1日释放后追踪至9月30日。主要结论有:(1)采用不含潮汐过程与包含潮汐过程的水动力模式分别对表层质点进行追踪,结果表明含潮汐混合和潮汐非线性效应的POM模式对质点时空分布的模拟较为可靠;(2)基于含潮汐过程的POM模式气候态模拟结果,考虑质点垂直运动进行追踪,质点运移速度较表层追踪大大减慢,进入朝鲜/对马海峡的质点减少;其中济州岛沿岸质点几乎全部穿过朝鲜/对马海峡进入日本海,其它释放区质点最终广泛分布在南黄海以及东海中陆架,主要在黄海潮汐锋区和长江口以南沿岸锋聚集;(3)通过分析不同释放时间对质点在9月末分布的影响发现,质点释放时间偏早,即水母幼体形成较早,将使相对较多的质点向朝鲜/对马海峡聚集。 相似文献
5.
K.-I. Chang W.J. Teague S.J. Lyu H.T. Perkins D.-K. Lee D.R. Watts Y.-B. Kim D.A. Mitchell C.M. Lee K. Kim 《Progress in Oceanography》2004,61(2-4):105
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. 相似文献
6.
The Korea (Tsushima) Strait is an important seaway through which the warm Tsushima Current flows into the East Sea (Japan
Sea). A paleogeographic map constrained by a regional sea-level curve developed on the basis of a number of recent 14C radiocarbon dates suggests that the Korea Strait was not closed during the last glacial period. Rather, it was open as a
channel-like seaway linking the western North Pacific and the East Sea. Some fraction of the paleo-Tsushima Current inflow
presumably continued at that time through the Korea Strait. The activity of the paleo-Tsushima Current is evidenced by the
distribution pattern of river-derived lowstand deposits, consisting of a beach/shoreface complex and lowstand deltaic wedges.
Received: 16 April 1999 / Revision accepted: 25 February 2000 相似文献
7.
Hideyuki Kawamura Toshimichi Ito Naoki Hirose Tetsutaro Takikawa Jong-Hwan Yoon 《Journal of Oceanography》2009,65(4):439-454
The branches of the Tsushima Warm Current (TWC) are realistically reproduced using a three-dimensional ocean general circulation
model (OGCM). Simulated structures of the First Branch and the Second Branch of the TWC (FBTWC and SBTWC) in the eastern Japan
Sea are mainly addressed in this study, being compared with measurement in the period September–October 2000. This is the
first numerical experiment so far in which the OGCM is laterally exerted by real volume transports measured by acoustic Doppler
current profiler (ADCP) through the Tsushima Straits and the Tsugaru Strait. In addition, sea level variation measured by
tide-stations along the Japanese coast as well as satellite altimeters is assimilated into the OGCM through a sequential data
assimilation method. It is demonstrated that the assimilation of sea level variation at the coastal tide-stations is useful
in reproducing oceanic conditions in the nearshore region. We also examine the seasonal variation of the branches of the TWC
in the eastern Japan Sea in 2000. It is suggested as a consequence that the FBTWC is continuous along northwestern Honshu
Island in summertime, while it degenerates along the coast between the Sado Strait and the Oga Peninsula in other seasons.
On the other hand, a mainstream of the SBTWC exists with meanders and eddies in the offshore region deeper than 1000 m to
the north of the Sado Island throughout the year. 相似文献
8.
Characteristics of water mass under the surface mixed layer in Tsushima Straits and the southwestern Japan Sea in autumn 总被引：1，自引：0，他引：1
Tetsutaro Takikawa Akihiko Morimoto Goh Onitsuka Atsushi Watanabe Masatoshi Moku 《Journal of Oceanography》2008,64(4):585-594
Two different cold waters were found under the surface mixed layer in Tsushima Straits and the southwestern Japan Sea in autumn
2004. One is cold saline water with a low concentration of dissolved oxygen, and the other is cold less saline water with
a high concentration of dissolved oxygen. The older saline water originates from the bottom of the East China Sea, strongly
influenced by the Kuroshio water with high salinity. The bottom density in the eastern channel of the Tsushima Straits is
coincident with that of the East China Sea in autumn, corresponding to the season when the cold saline water was frequently
found in the Tsushima Straits. The newer less saline water originates from the front of Tsushima Warm Current between the
Tsushima Warm Current water and the surface cold water in the Japan Sea. This water is formed by subduction above the isopycnal
surface from the front of the Tsushima Warm Current. 相似文献
9.
东海和南黄海夏季环流的斜压模式 总被引：17，自引：6，他引：17
基于拉格朗日余流及其输运过程的一种三维空间弱非线性理论，引进了黑潮边界力及长江径流，给出了东海和南黄海的夏季环流及上升流区的分布。计算结果表明：在黑潮西侧存在着台湾－对马暖流系统；进入朝鲜海峡的对马暖流来自台湾暖流、黑潮、东海混合水和西朝鲜沿岸流；黄海暖流主要来源于东海混合水，表面有部分来自对马暖流；闽浙沿岸存在上升流区且构成一带状区域；在长江口外、东海东北部和陆坡上也存在在上升流式；陆坡处上升流 相似文献
10.
Modeling of the wind-driven circulation in the Japan Sea using a reduced gravity model 总被引：1，自引：0，他引：1
The surface circulation in the Japan Sea is investigated using a 1.5 layer reduced gravity model. Historical observations suggest strongly that an anti-clockwise circulation is dominant in the subpolar region north of the Polar Front as a general feature. This anti-clockwise circulation as well as the branching of the Tsushima Warm Current was simulated well by incorporating the Naet al. (1992)'s wind stress. The positive curl of the wind stress in the northern and the northwestern Japan Sea was found to play an important role in the formation of the subpolar gyre and the separation of the western boundary current (the East Korean Warm Current) in the Japan Sea. 相似文献
11.
Water, Salt, Phosphorus and Nitrogen Budgets of the Japan Sea 总被引：1，自引：0，他引：1
Tetsuo Yanagi 《Journal of Oceanography》2002,58(6):797-804
Water, salt, phosphorus and nitrogen budgets of the Japan Sea have been calculated by box model analysis using historical
data. Average residence time of the Tsushima Warm Current Water in the upper 200 m is 2.1 years and that of the Japan Sea
Proper Water is 90 years. The salt flux from the Tsushima Strait balances those through the Tsugaru and Soya Straits. Average
residence times of phosphorus and nitrogen from the Tsushima Strait are 2.2 years and 1.6 years, respectively, in the upper
200 m of the Japan Sea. Total nitrogen/total phosphorus ratios of riverine load, the Tsushima Warm Current water and the water
in the Japan Sea are 16.4, 16.6 and 11.3, respectively. This suggests that denitrification is dominant in the Japan Sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
A significant surface net heat loss appears around the Kuroshio and the Tsushima Warm Current regions. The area where the
surface heat loss occurs should require heat to be supplied by the current to maintain the long-term annual heat balance.
Oceanic heat advection in these regions plays an important role in the heat budget. The spatial distribution of the heat supply
by the Tsushima Warm Current near the surface was examined by calculating the horizontal heat supply in the surface layer
of the East Sea (the Japan Sea) (ESJS), directly from historical sea surface temperature and current data. We have also found
a simple estimation of the effective vertical scale of heat supply by the current to compensate net heat loss using the heat
supplied by the current in the surface 10 m layer. The heat supplied by the current for the annual heat balance was large
in the Korea/Tsushima Strait and along the Japanese Coast, and was small in the northwestern part of the ESJS. The amount
of heat supplied by the current was large in the northwestern part and small in the south-eastern part of the ESJS. These
features suggest that the heat supplied by the Tsushima Warm Current is restricted to near the surface around the northeastern
part and extends to a deeper layer around the southeastern part of the ESJS.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Dong-Kyu Lee Peter Niiler 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(10):1222-1232
The mean circulation of the surface layer of the southwestern Japan/East Sea (JES) was examined using current measurements collected at 15 m by satellite-tracked drifters and merged sea level anomalies from satellite altimeters. The study of circulation patterns in this paper focused on the inflow passing through the western channel of the Korea Strait from the East China Sea. Empirical Orthogonal Function (EOF) analysis of non-seasonal sea level anomalies revealed that significant energy in the circulation pattern of Ulleung Basin was controlled by the inflow conditions through the Korea Strait. Three circulation patterns were identified that depended on the initial relative vorticity of the inflow. When inflow had initially large negative vorticity, the flow gained more negative vorticity due to deepening of the bottom (stretching) and then turned right after entering the JES. The inflow then followed the path of the Tsushima Warm Current along the coast of Japan. When the inflow was strong, with a speed in excess of 55 cm/s and with a large positive vorticity, potential vorticity appeared to be conserved. In this case, the EKWC followed isobaths along the coast and then left the coast, following topographic features north of Ulleung-Do. The northward flowing jet developed inertial meandering after leaving the coast, which is a characteristic of many western boundary currents. The regular, bimonthly deployments of drifters in the western portion of the Korea Strait revealed that splitting or branching of the flow through the western channel of the Korea Strait occurred only 15% of the time. And splitting or branching rarely occurred during the fall and winter seasons, when the inflow splitting was previously reported in hydrographic surveys. The time-averaged circulation map of the EKWC and its seaward extension were considerably enhanced by using regularly sampled geostrophic velocities calculated from sea level anomalies to remove biases in the mean velocity that were caused by irregular spatial and temporal drifter observations. The East Korean Warm Current, a mean coastal current along the Korean coast, behaved like the simple model by Arruda et al. (2004) in which the generation of the Ulleung Warm Eddy and the meandering circulation pattern were well reproduced. 相似文献
14.
In the current study, low-background γ-spectrometry was employed to determine the 228Ra/226Ra activity ratio and 137Cs activity of 84 coastal water samples collected at six sites along the main island of Japan (Honshu Island) within the Sea of Japan, including the Tsushima Strait, and two other representative sites on Honshu Island (a Pacific shore and the Tsugaru Strait) at 1-month intervals in 2006.The 228Ra/226Ra ratio of coastal waters in the Sea of Japan exhibited similar patterns of seasonal variation, with minimum values during early summer (228Ra/226Ra = 0.6–0.8), maximum values during autumn (228Ra/226Ra = 1.5–3), and a time lag in their temporal changes ( 2.5 months and over 1300 km distance). However, the 2 other sites represented no clear periodic variation.In contrast to the positive correlation between 137Cs activity (0.6–1.7 mBq/L) and salinity (15–35), the 228Ra/226Ra ratio of coastal water samples from the Sea of Japan was not observed to correlate with salinity, and the increase in the 228Ra/226Ra ratio was not as marked (0.5–1; May–June 2004 and 2005) during the migration along Honshu Island. The input of land-derived water and/or the diffusion of radium from coastal sediments is unlikely to have affected the wide seasonal variation in the 228Ra/226Ra ratio observed in these water samples.The seasonal variation in the 228Ra/226Ra ratio recorded for the coastal waters of the Sea of Japan is considered to be mainly controlled by the remarkable changes in the mixing ratio of the 228Ra-poor Kuroshio and the 228Ra-rich continental shelf waters within the East China Sea (ECS). After passing through the Tsushima Strait, this water mass moves northeast along the coastline of the Sea of Japan as the Tsushima Coastal Branch Current (TCBC). 相似文献
15.
16.
Masaki Kawabe 《Journal of Oceanography》1982,38(2):95-107
Although the Tsushima Current exhibits a complicated meander in the interior region of the Japan Sea, its path is more regular in the southwest region near the Tsushima Strait, and three branches have often been recognized there by many investigators. However, the detailed structures and temporal variabilities of these branches have not been clarified, and so they are studied here by analysing temperature, salinity and sea level data. It is shown that the existence of the first branch (the nearshore branch along the Japanese coast) can be detected from salinity distributions at least during the period from March to August. The third branch (the Eastern Korean Current) exists in all seasons. On the other hand, the second branch (the offshore branch) is seasonally variable and can be identified only in summer from June to August. Along the Japanese coast of southwest Japan Sea, the main pycnocline intersects the gentle slope on the shelf at a depth between 150 and 200 m. The first branch is found on the coastal side of the line where the main pycnocline intersects the bottom slope. On the other hand, the second branch is formed just on the seaward side of this line. Sea level differences in the Tsushima Strait, i.e., between Hakata and Izuhara and between Izuhara and Pusan, show that the seasonal variation of the surface velocity (or volume transport) is small in the eastern channel and large in the western channel. The period during which the surface velocity and volume transport in the western channel increase corresponds well to the period during which the second branch exists. These results suggest that the effects of bottom topography and oceanic stratification in the Japan Sea as well as the time variation of inflow through the western channel of the Tsushima Strait play important roles in the formation of the second branch. 相似文献
17.
The Japan Sea is one of the eddy-rich areas in the world. Many researchers have described the variability of the eddy field and its structure in the Tsushima Warm Current region. On the other hand, since there are few data covering the northern part of the Japan Sea, we are not able to understand the detailed variability of the eddy field there. The variation of the eddy field in the Japan Sea is investigated using the temporal fluctuations of sea surface height measured by altimetric data from TOPEX/POSEIDON and ERS-2. Tidal signals are eliminated from the altimetric data on the basis of the results of Morimoto et al. (2000). Distributions of sea surface dynamic height are produced by using the optimal interpolation method every month. The distributions warm and cold eddies that we obtained coincide well with the observed isotherms at 100 m depth measured by the Japan Sea National Fisheries Research Institute and the sea surface temperature measured by satellite. There are areas with high RMS variability of temporal fluctuation of sea surface dynamic height in the Yamato Basin, the Ulleung Basin, east of North Korea, the eastern part of the Yamato Rise, the Tsushima Strait and west of Hokkaido. The characteristics of eddy propagation in the high RMS variability regions are examined using a lag correlation analysis. Seasonal variations in the number of warm and cold eddies are also examined. 相似文献
18.
The northward intruding eddy along the East coast of Korea 总被引：5，自引：0，他引：5
The current structures and their seasonal variations in the East Korean Warm Current (EKWC) region, which plays a significant role in the northward transport of warm and saline waters, were described by combining the sea surface temperature (SST) data of consecutive satellite inferred (IR) images and hydrographic data. The SST patterns in winter-spring clearly showed that the small meander of thermal front originating from the Tsushima/Korea Strait formed close to the Korean coast and grew an isolated warm eddy with horizontal dimension of order 100 km. Such warm eddy began to intrude slowly northward from spring to summer. At that time, interactions with neighboring synoptic warm eddy [Ks] around the Ulleung Basin were found to have strongly influence the movement of the intruding eddy and its structural change. In autumn, after the northward movement stopped at the north of eddy [Ks], the relative stable northward current along the Korean coast were formed. The evidence from observational results does not support a persistent branching of the EKWC from the Tsushima/Korea Strait, but a seasonal episodic supply of warm and saline waters due to the northward intruding eddy process described above. 相似文献
19.
Yutaka Isoda 《Journal of Oceanography》1999,55(5):585-596
The most plausible scenarios for seasonal to interannual variabilities and their possible causes are investigated for the Tsushima Current system passing through the Japan Sea. The study is based on the north and south two-box model across the polar front in an idealized upper ocean of the Japan Sea. The boxes are connected by lateral diffusive heat transport and cooled by atmospheric forcing at the annual mean state. The south box, i.e. the Tsushima Current region, only interacts with the outside warmer box in the East China Sea and has an eastward thermal-driven current originating in the outside box. The magnitude of this current depends on the strength of the thermal gradient between the north and south boxes; the inflow of warm waters can therefore be maintained by net heat loss through the sea-surface. I call such a thermal-driven inflow process a "Cooling-Induced Current" system in the present study. Under periodical heat forcing, the perturbation response of the model to water temperature fields and inflow transport were examined. It is shown that the lateral diffusion time across the polar front (over a period of 10 years) is crucial to the interannual modeled response. An analysis of the seasonal heat budget suggests that the heat transported into the Japan Sea from the East China Sea in summer is stored mainly within the Tsushima Current region and contributes to heat loss by the sea-surface cooling in winter. 相似文献
20.
In order to clarify the formation and circulation of the Japan/East Sea Intermediate Water (JESIW) and the Upper portion of
the Japan Sea Proper Water (UJSPW), numerical experiments have been carried out using a 3-D ocean circulation model. The UJSPW
is formed in the region southeast off Vladivostok between 41°N and 42°N west of 136°E. Taking the coastal orography near Vladivostok
into account, the formation of the UJSPW results from the deep water convection in winter which is generated by the orchestration
of fresh water supplied from the Amur River and saline water from the Tsushima Warm Current under very cold conditions. The
UJSPW formed is advected by the current at depth near the bottom of the convection and penetrates into the layer below the
JESIW. The origin of the JESIW is the low salinity coastal water along the Russian coast originated by the fresh water from
the Amur River. The coastal low salinity water is advected by the current system in the northwestern Japan Sea and penetrates
into the subsurface below the Tsushima Warm Current region forming a subsurface salinity minimum layer.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献