• Journal of the korean society of oceanography
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• 제39권3호
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• pp.155-162
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• 2004

The variation of volume transport during the period from 1965 to 2000 through the western channel of the Korea Strait was estimated by obtaining an relation function between the ADCP volume transport and the geostrophic volume transport estimated by the sea level difference between Pusan and Izuhara. The estimated climatological mean volume transport during past 36 years has seasonal variation with a minimum of 1.15 Sv in February and a maximum of 1.88 Sv in October. The mean volume transport for 36 years is 1.51 Sv. The annual mean volume transport has an interannual variation with a minimum of 1.26 Sv in 1968 and maximum of 1.90 Sv in 1973, with three dominant periods of variations of 14.96 years, 4.96 years and 2.99 years.

• Ocean and Polar Research
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• 제31권4호
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• pp.283-296
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• 2009

Oceanographic survey data were analyzed to understand the characteristics of a warm eddy observed in the Ulleung Basin in July 2005. The temperature distribution at 200 db and vertical sections provided evidence of the warm eddy in the Ulleung Basin (UWE05). Based on the 5$^{\circ}C$ isothermal line on 200 db temperature, the major axis was 160 km from southwest to northeast, and the minor axis was 80 km from southeast to northwest. The homogeneous layer in the thermocline of UWE05 had mean values of 10.40$^{\circ}C$ potential temperature, 34.35 psu salinity, and 26.37 kg/m$^3$ potential density (${\sigma}_{\theta}$) and provided evidence that UWE05 also existed during the winter of 2004-2005. A warm streamer initially flowed along the circumference of UWE05 and mixed with the upper central water. Two northward current cores were found on the western side of the measured current section at the central latitude of UWE05. One was the East Korean Warm Current (EKWC) and the other was the main stream of the western part of UWE05. Geostrophic transport of the upper layer (from the surface to the isopycnal surface of 26.9 ${\sigma}_{\theta}$) was approximately 2.5 Sv in the eastern side of UWE05. However, the measured transport was twice as large as the geostrophic transport. Mass conservation of geostrophic transport was well satisfied in the upper layer. The direct current measurements and geostrophic transport analysis showed that the EKWC meandered around UWE05.

• Ocean and Polar Research
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• 제21권2호
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• pp.99-108
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• 1999

With sectional data obtained in September of 1987, 1988 and 1989 by quadrireciprocal ADCP measurement and CTD cast, the current structure, volume transport and vorticity in the Western Channel of the Korea Strait were studied. The characteristics of Tsushima Current water persisted throughout the summer especially in the homogeneous water of temperature $14-16^{\circ}C$ located at the depth of 50-100m below seasonal termocline. Thickness and velocity of the homogeneous layer are about 10-170m and 20-60cm/s. and the relative vorticity for this layer is shown to be nearly constant and it is smaller than the planetary vorticity. Potential vorticity of $2.70-7.10{\times}10^{-6}m^{-1}s^{-1}$ is found to be dependent mainly on planetary rather than on the relative vorticities. The Tsushima Current water represented by the homogeneous layer R14-16^{\circ}C$ may keep the potential vorticity at the area of strong current in the Strait. The ADCP current structure is similar to geostrophic current and the core of the current with the speed of 30-50cm/s is situated in the middle layer over the deep trough. With large tidal fluctuation the volume transport has mean value of 1.17sv which was about 40% larger than that of geostrophic calculation.

• 대한원격탐사학회지
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• 제9권1호
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• pp.79-93
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• 1993

NOAA AVHRR의 MCSST를 이용하여 지형류의 상대속도를 추정하였으며 이것을 대한 해협에 적용하였다. 원격탐사는 관측시에 광범위한 지역에 대해서 동시성 및 반복성이 유지되기 때문에 해양현상을 연구하는 데 있어서 훌륭한 도구로써 쓰일 수 있다. 특히 AVHRR 자료는 높 은 분해능으로 인해서 선상관측 자료보다도 지형류를 더욱 정밀하게 구할 수 있다. 연구 결과에 의하면 1992년 4월에 대한해협 서수도에서의 상대속도는 골이 있는 해역에서 가장 크며 이때 유 속의 크기는 약 23.8cm/sec로 나타났다. 그러나 이 결과는 geopotential anomaly를 계산할 때 염 분의 효과를 무시한 만큼의 오류를 포함하고 있다. 또한 대한해협 서수도에서 지형류의 수송량은 약 0.3Sv이며 쓰시마와 골이 있는 해역 사이에서 수송량이 가장 큰 것으로 나타났다.

• 한국해양학회지
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• 제20권1호
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• pp.50-55
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• 1985

대한해협과 동부중부 단면에서 1969년부터 1974년까지, 국립수산진흥원 관측 자료와 일본기상청와관측자료를 이용하여, 동절기와 하절기로 구분하여 두 단면을 통과하는 지형류의 유속과 용적수송량을 비교분석했다. 대한해협을 통해서 동해로 유입되는 누년평균 순용적수송량은, 동절기에는 0.19$\times$$10^{6}$m$^{3}$sec이고 , 하절기에는 1.33$\times$$10^{6}$m$^{3}$sec이다. 동절기에는 동수도와 서수도를 통해서 동해로 유입되는 수송량이 거의 같은 값을 보이나, 하절기에는 서수도를 통해서 동 해로 유입되는 수송량이 동수도보다 훨씬크다. 동해중부단면을 통과하는 누년평균 순용적수송량은, 동절기에는 2.61$\times$$10^{6}$m$^{3}$sec이고 , 하절기에는 2.41$\times$$10^{6}$m$^{3}$sec로서 본 단면에서는 동절기와 하절기에 거의 같은 수송 량을 보인다. 두 단면에서 동절기와 하절기의 수송량 값을 비교하면, 동절기에는 대 한해협보다 동해 중부단면을 통과하는 유량이 13.7배 정도 크고 하절기에는 1.8배 정도 크게 나타난다.

• 한국수산과학회지
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• 제30권5호
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• pp.759-770
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• 1997

제주해협내에 설정한 3개의 남북 단면상에 배열한 13개의 관측정점과 기타 4개의 제주항 부근의 연안정점에서 $1986\~1989$년까지 실시한 해류계에 의한 해류조사결과와 $1981\~1987$년 사이에 실시된 해류판 추적조사, 일반해양관측 등에 의하여 얻어진 자료들을 종합적으로 분석하여 정리한 제주해협의 유황을 요약하면 다음과 같다. 1. 제주해협내에는 주로 동$\~$북동류의 항류가 있어, 해협 서쪽 입구의 전단면을 통하여 해협내로 유입된 해수가 동쪽 입구의 전단면을 통하여 유출되고 있으며, 이 항류의 유속은 10m층에서 $5.2cm/sec\~30cm/sec$이고, 중${\cdot}$저층은 $1.3\~24cm/sec$로 대체로 해협의 심소 및 제주도 북측에 강류대가 있고, 추자도 및 보길도 부근의 연안 천소에 악한 항류가 있다. 2. 제주해협 서쪽 입구의 전단면에서 실측한 항류의 하계 평균유속은 6.93cm/sec로, 이것을 기초로 계산한 이 단면의 해수수송량은 $0.384\times10^6\;m^3/sec(Sv)$이며, 단면의 항류분포와 지형류 유속 분포간에는 많은 차를 보였다. 3. 추자도 북서쪽의 전선역에서는 밀물 때는 북향류에 의해 고온${\cdot}$고염분의 외해수가 5mile정도 연안역으로 이동 하지만, 썰물 때는 북상 거리만큼 다시 남하하지 않고 동$\~$남동향류 때문에, 연안수와 혼합하면서 전선북쪽의 연안역으로 이동하므로, 결과적으로 추자도 북서해역은 제주도 서방해역으로 부터 북상해온 외해수가 한국남해연안수내로 유입하는 창구가 되며, 이것을 일으키는 주된 작용은 항류가 아닌 조류이다.

• Ocean Science Journal
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• 제40권1호
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• pp.25-44
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• 2005

Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties, current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB) in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the eastern coast of Korea. Long-tenn current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST), sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic processes in the East Sea.