• Title/Summary/Keyword: Tsushima

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A simple Model for Separation of the Tsushima Current Stream Core by the Tsushima Island: a small viscosity limit

  • Seung, Young-Ho
    • Journal of the korean society of oceanography
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    • v.38 no.2
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    • pp.45-51
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    • 2003
  • Recent observations reveal that the Tsushima Current has a double-cored structure downstream of the Tsushima Island. To explain this, a simple analytical model is proposed based on the assumption of small lateral eddy viscosity. This model suggests that an otherwise uniform current becomes to have a stream core immediately after it enters a channel due to the action of lateral friction. The core is initially broad but becomes sharper downstream. The speed at which the core develops depends on the intensity of lateral eddy viscosity. Likewise, a single-cored stream changes rapidly to a double-cored stream when it passes through an island located in the center of the channel. When the stream leaves the island behind, the reverse process from the double-to single-cored structures takes place. In this case, however, the double-cored structure is retained for a significant distance from the island. Overall, this model suggests that the double-cored structure of the Tsushima Current observed downstream of the Tsushima Island Is created by the lateral friction exerted by the Tsushima Island.

The Regional Development Strategy by Public-Private Activities: A Case Study of the Tsushima Arirang Festival, Tsushima, Nagasaki Province, Japan (민.관의 활동에서 본 쓰시마시의 지역 활성화 정책: 아리랑 축제를 사례로)

  • Shin, Young-Kun
    • Journal of the Korean Geographical Society
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    • v.43 no.6
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    • pp.951-960
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    • 2008
  • This paper examines how Tsushima has used the Arirang festival as a place marketing apparently targeting at Korean tourists, which has been historically achieved at the Arirang festival though public-private activities. Tsushima has tried to advertise Tsushima city to Korean tourists, with methods including the 'Chosen Agency Parade' and the title of the Arirang festival, but due to the Dokdo problem, the people of Tsushima objected to holding the Arirang festival. Therefore, Tsushima city had a meeting to solve it, and it was agreed that they need not stop the festival nor change of the title of the Arirang festival for the regional development, but instead they decided that the title of Arirang festival is to be used as a subtitle from 2007. By deciding this, The residents of Tsushima are sometimes against the opinion of Tsushima government, but they have eagerly participated in everything from the operation of the festival to the performances themselves. In this sense, it is thought that the Arirang festival is utilized as a local identity and also a place marketing, and the process for the regional development strategy is organized by public-private actors together.

Paleo-Tsushima Water influx to the East Sea during the lowest sea level of the late Quaternary

  • Lee, Eun-Il
    • Journal of the Korean earth science society
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    • v.26 no.7
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    • pp.714-724
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    • 2005
  • The East Sea, a semi-enclosed marginal sea with shallow straits in the northwest Pacific, is marked by the nearly geographic isolation and the low sea surface salinity during the last glacial maximum (LGM). The East Sea might have the only connection to the open ocean through the Korea Strait with a sill depth of 130 m, allowing the paleo-Tsushima Water to enter the sea during the LGM. The low paleosalinity associated with abnormally light $\delta^{18}O$ values of planktonic foraminifera is interpreted to have resulted from river discharge and precipitation. Nevertheless, two LGM features in the East Sea are disputable. This study attempts to estimate volume transport of the paleo-Tsushima Water via the Korea Strait and further examines its effect on the low sea surface salinity (SSS) during the lowest sea level of the LGM. The East Sea was not completely isolated, but partially linked to the northern East China Sea through the Korea Strait during the LGM. The volume transport of the paleo-Tsushima Water during the LGM is calculated approximately$(0.5\~2.1)\times10^{12}m^3/yr$ on the basis of the selected seismic reflection profiles along with bathymetry and current data. The annual influx of the paleo-Tsushima Water is low, compared to the 100 m-thick surface water volume $(about\;79.75\times10^{12}m^3)$ in the East Sea. The paleo-Tsushima Water influx might have changed the surface water properties within a geologically short time, potentially decreasing sea surface salinity. However, the effect of volume transport on the low sea surface salinity essentially depends on freshwater amounts within the paleo-Tsushima Water and excessive evaporation during the glacial lowstands of sea level. Even though the paleo-Tsushima Water is assumed to have been entirely freshwater at that time period, it would annually reduce only about 1‰ of salinity in the surface water of the East Sea. Thus, the paleo-Tsushima Water influx itself might not be large enough to significantly reduce the paleosalinity of about 100 m-thick surface layer during the LGM. This further suggests contribution of additional river discharges from nearby fluvial systems (e.g. the Amur River) to freshen the surface water.

On the Origin of the Tsushima Current Water

  • Lim, Du Byung
    • 한국해양학회지
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    • v.6 no.2
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    • pp.85-91
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    • 1971
  • The origin of the Tsushima Current water was investigated with a discussion on the western North Pacific Central Water. The Tsushima Current water is formed by the mixing of the Kuroshio surface water and the East China Sea water. The area where the mixing takes place remarkably is found to be the marginal region of the continental shelf of the East China Sea at the depth from 100 to 200 meters.

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A Numerical Model on the Inflow into the Japan Sea: the Formation and Transport of the Tsushima Warm Current (동해 해수유입에 대한 수치모델: 대마난류 형성 및 수송량)

  • NAM Soo-Yong;SEUNG Yong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.1
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    • pp.58-64
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    • 1992
  • A barotropic model is run over the Northwest Pacific Ocean to examine the formation and transport of the Tsushima Warm Current. The results indicate that the Tsushima Warm Current is a downstream extension of the Taiwan Warm Current. Local wind does not change the amount of transport of Tsushima Warm Current but it changes much the initial flow pattern of Tsushima Warm Current such that for southerly wind, the transport is through the Taiwan Strait but for northerly wind, it is through the eastern side of Taiwan.

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Changes in the Tsushima Warm Current and the Impact under a Global Warming Scenario in Coupled Climate Models (기후모델에 나타난 미래기후에서 쓰시마난류의 변화와 그 영향)

  • Choi, A-Ra;Park, Young-Gyu;Choi, Hui Jin
    • Ocean and Polar Research
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    • v.35 no.2
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    • pp.127-134
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    • 2013
  • In this study we investigated changes in the Tsushima Warm Current (TWC) under the global warming scenario RCP 4.5 by analysing the results from the World Climate Research Program's (WCRP) Coupled Model Intercomparison Project Phase 5 (CMIP5). Among the four models that had been employed to analyse the Tsushima Warm Current during the 20th Century, in the CSIRO-Mk3.6.0 and HadGEM2-CC models the transports of the Tsushima Warm Current were 2.8 Sv and 2.1 Sv, respectively, and comparable to observed transport, which is between 2.4 and 2.77 Sv. In the other two models the transports were much greater or smaller than the observed estimates. Using the two models that properly reproduced the transport of the Tsushima Warm Current we investigated the response of the current under the global warming scenario. In both models the volume transports and the temperature were greater in the future climate scenario. Warm advection into the East Sea was intensified to raise the temperature and consequently the heat loss to the air.

Effects of Human Activities on Home Range Size and Habitat use of the Tsushima leopard Cat Prionailurus bengalensis euptilurus in a Suburban Area on the Tsushima Islands, Japan

  • Oh, Dae-Hyun;Moteki, Shusaku;Nakanish, Nozomi;Izawa, Masako
    • Journal of Ecology and Environment
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    • v.33 no.1
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    • pp.3-13
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    • 2010
  • The Tsushima leopard cat, Prionailurus bengalensis euptilurus, a small felid, inhabits only the Tsushima Islands in Japan. Previous studies of the Tsushima leopard cat revealed that natural factors; including sex, reproductive activity, season, and prey distribution and abundance affect leopard cat home range variation and habitat use. In this study, we focused on clarifying how anthropogenic factors influenced home range variation and habitat use of a male Tsushima leopard cat living near a suburban area in January, March, May and September 2005 using radio-tracking. The home range size (100% MCP) of this cat was $0.78\;{\pm}\;0.26\;km^2$ (mean ${\pm}$ SD, n = 4 tracking sessions) across the whole study period. However, the cat did not use all parts of its home range uniformly; rather it used some habitat types selectively. The cat avoided agriculture areas and residential areas in all of the tracking-sessions. On the other hand, the cat showed a weak preference for artificial structures and a strong preference for baiting sites in January and March, while it avoided them in May, and no baiting site was included in its home range in September. These results suggest that anthropogenic factors influenced the ranging patterns and habitat use of the leopard cat living near a suburban area. Artificial structures might provided good resting spaces for the cat in bad weather. When the density of its main prey was low in the winter, the cat tended to rely on artificial prey and had a small home range size.

A Review of Ocean Circulation of the East/Japan Sea (한국 동해 해수순환의 개략적 고찰)

  • 김종규
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.103-107
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    • 2001
  • The major studies of an ocean circulation of the East/Japan Sea related to evaluate the feasibility and utilization of deep ocean water are reviewed. The major feature of surface current system of the East/Japan Sea is an inflow of the Tsushima Warm Current through the Korea/Tsushima Strait and the outflow through the Tsugaru and Soya Straits. The Tsushima Warm Current has been known to split into two or three branches in the southern region of the East/Japan Sea. In the cold water region of the East/Japan Sea, the North Korean Cold Current turns to the east near 39$^{\circ}$N after meeting the East Korean Warm Current, then flows eastward. The degree of penetration depends on the strength of the positive wind stress curl, according to the ventilation theory. Various current meter moorings indicate strong and oscillatory deep currents in various parts of the basin. According to some numerical experiments, these currents may be induced by pressure-topography or eddy-topography interaction. However, more investigations are needed to explain clearly the presence of these strong bottom currents. This study concludes the importance of topographical coupling, isopycnal outcropping, different wind forcing and the branching of the Tsushima Warm Current on the circulation of the East/Japan Sea.

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The Tsushima Warm Current from a High Resolution Ocean Prediction Model, HYCOM (고해상도 해양예보모형 HYCOM에 재현된 쓰시마난류)

  • Seo, Seongbong;Park, Young-Gyu;Park, Jae-Hun;Lee, Ho Jin;Hirose, N.
    • Ocean and Polar Research
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    • v.35 no.2
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    • pp.135-146
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    • 2013
  • This study investigates the characteristic of the Tsushima Warm Current from an assimilated high resolution global ocean prediction model, $1/12^{\circ}$ Global HYbrid Coordiate Ocean Model (HYCOM). The model results were verified through a comparison with current measurements obtained by acoustic Doppler current profiler (ADCP) mounted on the passenger ferryboat between Busan, Korea, and Hakata, Japan. The annual mean transport of the Tsushima Warm Current was 2.56 Sverdrup (Sv) (1 Sv = $10^6m^3s^{-1}$), which is similar to those from previous studies (Takikawa et al. 1999; Teague et al. 2002). The volume transport time series of the Tsushima Warm Current from HYCOM correlates to a high degree with that from the ADCP observation (the correlation coefficient between the two is 0.82). The spatiotemporal structures of the currents as well as temperature and salinity from HYCOM are comparable to the observed ones.

Estimated Advection Heat in the East/Japan Sea

  • Han, In-Seong;Kang, Yong-Q;Kim, Bok-Kee;Seong, Ki-Tack
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2003.11a
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    • pp.165-170
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    • 2003
  • 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/Japan Sea, 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 10m 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 East/Japan Sea. The amount of heat supplied by the current was large in the northwestern part and small in the southeastern part of the East/Japan Sea. 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 East/Japan Sea.

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