• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.418-426
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• 2015

Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.273-284
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• 2002

The Gravity-Geologic Method (GGM) was implemented for bathymetric determinations in the Drake Passage, Antarctica, using global marine Free-air Gravity Anomalies (FAGA) data sets by Sandwell and Smith (1997) and local echo sounding measurements. Of the 6548 bathymetric sounding measurements, two thirds of these points were used as control depths, while the remaining values were used as checkpoints. A density contrast of 9.0 gm/㎤ was selected based on the checkpoints predictions with changes in the density contrast assumed between the seawater and ocean bottom topographic mass. Control depths from the echo soundings were used to determine regional gravity components that were removed from FAGA to estimate the gravity effects of the bathymetry. These gravity effects were converted to bathymetry by inversion. In particular, a selective merging technique was developed to effectively combine the echo sounding depths with the GGM bathymetiy to enhance high frequency components along the shipborne sounding tracklines. For the rugged bathymetry of the research area, the GGM bathymetry shows correlation coefficients (CC) of 0.91, 0.92, and 0.85 with local shipborne sounding by KORDI, GEODAS, and a global ETOPO5 model, respectively. The enhanced GGM by selective merging shows imploved CCs of 0.948 and 0.954 with GEODAS and Smith & Sandwell (1997)'s predictions with RMS differences of 449.8 and 441.3 meters. The global marine FAGA data sets and other bathymetric models ensure that the GGM can be used in conjunction with shipborne bathymetry from echo sounding to extend the coverage into the unmapped regions, which should generate better results than simply gridding the sparse data or relying upon lower resolution global data sets such as ETOPO5.

• 한국해양학회지
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• v.30 no.2
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• pp.91-115
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• 1995

Air-sea heat fluxes in the East Sea were estimated from the various ship's data observed from 1961 to 1990 and the JMA buoy #6 data from 1976 to 1985. The oceanic heat transport in the sea was also determined from the fluxes above and the heat storage rate of the upper layer of 200m from the sea surface. In winter, The incoming solar radiation is almost balanced with the outgoing longwave radiation. but the sea loses her heat through the sea surface mainly due to the latent and sensible heat fluxes. The spatial variation of the net surface heat flux is about 100 Wm/SUP -2/, and the maximum loss of heat is occurred near the Tsugaru Strait. There are also lots of heat losses in the southern part of the East Sea, Korea Strait and Ulleung Basin. Particularly, the heat strong loss in the south-western part of the sea might be concerned with the formation of her Intermediate Homogeneous Water. In summer, the sea is heated up to about 120∼140 Wm/SUP -2/ sue to strong incoming solar radiation and weak turbulent heat fluxes and her spatial variation is only about 20 Wm/SUP -2/. The oceanic heat flux is positive in the southeasten part f the sea and the magnitude of the flux is larger than that of the net surface heat flux. This shows the importance of the area. In the southwestern part of the sea, however, the oceanic heat flux is negative. This fact implies cold water inflow, the North Korean Cold Water. The sigh of net surface heat flux is changed from negative to positive in March and from positive to negative in September. The heat content in the upper surface 200 m from the sea surface reaches its minimum in March and maximum in October. The annual variation of the net surface heat flux is 580 Wm/SUP -2/ in southwestern part of the sea. The annual mean values of net surface heat fluxes are negative, which mean the net heat transfer from the sea to the atmosphere. The magnitude of the flux is about 130 Wm/SUP -2/ near the Tsugaru Strait. The net surface fluxes in the Korea Strait and the Ulleung Basin are relatively larger than those of the rest areas. The spatial mean values of surface heat fluxes from 35$^{\circ}C$ to 39$^{\circ}$N are 129, -90, -58, and -32 Wm/SUP -2/ for the incoming solar radiation, latent hear flux, outgoing longwave radiation, and sensible heat flux, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.241-247
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• 1995

A time mean surface velocity field was estimated from AVHRR/SST in the Korea Strait. Time duration of SST data set was not different from tidal period and tidal elimination was investigated. The velocity field was estimated by inverse method and compared with results of ADCP observation and results of Odamaki(1989). In accordance with results. tidal component was eliminated partially in case that there were a little difference between total time interval of 557 data set and tidal period.

• Ocean and Polar Research
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• v.26 no.4
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• pp.581-594
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• 2004

CREAHS II carried out an intensive hydrographic survey covering almost entire East Sea in 1999. Hydrographic data from total 203 stations were released to public on the internee. This paper summarized the results of water mass analysis by OHP (Optimum Multiparameter) method that utilizes temperature, salinity, dissolved oxygen, pH, alkalinity, silicate, nitrate, phosphate and location data as an input data-matrix. A total of eight source water types are identified in the East Sea: four in surface waters(North Korea Surface Water, Tatar Surface Cold Water, East Korean Coastal Water, Modified Tsushima Surface Water), two intermediate water types (Tsushima Middle Water, Liman Cold Water), two deep water types (East Sea Intermediate Water, East Sea Proper Water). Of these NKSW, MTSW and TSCW are the newly reported as the source water type. Distribution of each water types reveals several few interesting hydrographic features. A few noteworthy are summarized as follows: The Tsushima Warm Current enter the East Sea as three branches; East Korea Coastal Water propagates north along the coast around $38^{\circ}N$ then turns to northeastward to $42^{\circ}N$ and moves eastward. Cold waters of northern origin move southward along the coast at the subsurface, which existence the existence of a circulation cell at the intermediate depth of the East Sea. The estimated volume of each water types inferred from the OMP results show that the deep waters (ESIW + ESPW) fill up ca. 90% of the East Sea basins. Consequently the formation and circulation of deep waters are the key factors controlling environmental condition of the East Sea.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.427-434
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• 2004

해양지명은 자연적으로 형성된 해양ㆍ해협ㆍ만ㆍ포 및 수로 등의 이름과 초ㆍ퇴ㆍ해저협곡해구 등 해저지형의 이름이다. 지명의 표준화란 지명을 통일(standardization of geographical names)하는 과정으로서 특정의 지리적 장소, 특색, 지역에 대하여 각각 공식적인 이름을 부여하여 표기하는 것이다. 해양지명 표준화는 각 개별국가들이 해도 및 해양간행물에서 통일된 해양지명을 사용하게 함으로써 항행의 안전을 도모하기 위하여 필요한 사업이며 해양측량기술이 발달하면서 해저지형에 대한 측량과 지명부여가 중요한 과제로 인식되고 있다 국내적으로 통일되고 국제적으로 공유될 수 있는 정확한 해양지명 부여를 위한 해양지명표준편람의 제작 목적과 방향에 관하여 연구하고 앞으로 해양지명위원회의 활동방향을 제시하였다.

• Animal Systematics, Evolution and Diversity
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• v.19 no.2
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• pp.257-265
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• 2003

The genus Nippoleucon was newly established within the family Leuconidae and two Hemileucon species, N. hinumensis (Gamo, 1967) and N. enoshimensis (Gamo, 1967), were transferred to this genus. Through examination of the cumacean specimens from the Gwangyang Bay of the Korea Strait, N. hinumensis is recorded as new to Korean fauna. The genus Nippoleucon is reported from Korea for the first time.

• 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.

• Animal Systematics, Evolution and Diversity
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• v.21 no.2
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• pp.201-205
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• 2005

Some siphonophores were collected from the Korea Strait, $33^{\circ}59'N-129^{\circ}17'E$ and Yeosu with Issacs-Kidd Midwater trawl net in Sep. 2002. They were identified into Diphyes chamissonis is Huxley, 1859 and Abylopsis eschscholtzi(Huxley, 1859) in the suborder Calycophorae of the order Siphonophora, respectively. They are new to the Korean fauna. As a result of this work, six siphonophores of four families have been reported in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.393-403
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• 2016

A steady, strong southward flow was observed in the lower layer beneath the Tsushima Warm Current in the deepest trough of the Korea Strait. Known as the Korea Strait Bottom Cold Water (KSBCW), this bottom current had a mean velocity of 24 cm/s and temperatures below 8–10℃. The direction of the bottom current was highly stable due to the topographic effects of the elongated trough. To determine the path of the southward bottom current, ADCP (Acoustic Doppler Current Profiler) data from 14 stations between 1999 and 2005 were examined. Persistent southward flows with average speeds of 4–10 cm/s were observed at only three places to the north of the strait where the bottom depths were 100–124 m. The collected data suggest a possible course of the southward bottom current along the southeast Korean coast before entering the deep trough of the Strait.