• 한국해양학회지:바다
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• 제4권4호
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• pp.305-311
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• 1999

라디움(Ra) 동위원소 분포특성을 이용하여 동중국해와 남중국해 여름철 표층수의 해수의 조성을 밝히고자 하였다. 염분과 라디움 동위원소 방사능비($^{228}Ra/^{226}Ra$)의 분포는 동중국해와 남중국해에서 각기 쿠로시오 표층수와 장강 희석수, 쿠로시오 표층수와 연안 희석수의 두 단성분 해수의 단순혼합으로 설명하기에 적절하게 점진적으로 변화하는 분포양상을 나타냈다. 동중국해의 경우에 두 단성분 해수의 혼합은 Ra 동위원소비와 염분의 두 추적자로 각각 정량화가 가능하였는데, 결과를 비교해 보면 쿠로시오에 가까운 정점에서는 매우 비슷한 결과를 보였으나 대마난류가 분지된 이후부터는 차이가 커지기 시작하였다. 이러한 차이를 보이게 하는 가능한 요인으로 중층수와의 혼합이 지목되었다. 이 경우 염분과 Ra 동위원소비는 서로 반대방향으로 교란될 것으로 예상된다. 즉 염분은 저염수의 기여도를 과소평가하는 방향으로 반대로 Ra 동위원소비는 과대평가하게 되므로 두 결과값의 중간값이 실제에 가까울 것으로 판단되었다.

• Ocean and Polar Research
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• 제30권3호
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• pp.361-372
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• 2008

A satellite tracked drifter experiment was conducted to observe thermal structure and surface circulation in the northeastern East China Sea. For this experiment, four ADOS buoys, assembled with surface float and thermister chain, were deployed on August 2007 in southern Jeju-do, where the Kuroshio Branch Current is separated from the main stream. Thermal structure in the upper layer of the northeastern East China Sea was successfully observed during the following $1{\sim}3$ months. Strong thermo-haline front in a northeast-southwest direction was observed. In the frontal zone, warm and saline Kuroshio origin water intermixes with fresher coastal water and flows toward the Korean Strait. Typhoon Nari, which passed over the East China Sea 20 days after commencement of study, caused distinct signals in the thermal structure and trajectory of buoys. During the typhoon, surface temperature abruptly dropped to about $4^{\circ}C$, while the thermocline formed at $30{\sim}50$ m depth vanished due to strong vertical mixing. Internal inertial oscillation occurred several days after the typhoon. The fortuitous occurrence of typhoon Nari showed that ADOS buoys can provide useful and accurate air-sea interaction data during typhoons.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.831-835
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• 2006

NOAA/AVHRR data were used to analyze sea surface temperatures (SSTs) and thermal fronts (TFs) in the Korean seas. Temporal and spatial analyses were based on data from 1993 to 2000. Harmonic analysis revealed mean SST distributions of $10{\sim}25^{\circ}C$. Annual amplitudes and phases were $4{\sim}11^{\circ}C$ and $210{\sim}240^{\circ}$, respectively. Inverse distributions of annual amplitudes and phases were found for the study seas, with the exception of the East China Sea, which is affected by the Kuroshio Current. Areas with high amplitudes (large variations in SSTs) showed 'low phases' (early maximum SST); areas with low amplitudes (small variations in SSTs) had 'high phases' (late maximum SST). Empirical orthogonal function (EOF) analyses of SSTs revealed a first-mode variance of 97.6%. Annually, greater SST variations occurred closer to the continent. Temporal components of the second mode showed higher values in 1993, 1994, and 1995. These phenomena seemed to the effect of El $Ni{\tilde{n}}o$. The Sobel edge detection method (SEDM) delineated four fronts: the Subpolar Front (SPF) separating the northern and southern parts of the East Sea; the Kuroshio Front (KF) in the East China Sea, the South Sea Coastal Front (SSCF) in the South Sea, and a tidal front (TDF) in the West Sea. Thermal fronts generally occurred over steep bathymetric slopes. Annual amplitudes and phases were bounded within these frontal areas. EOF analysis of SST gradient values revealed the temporal and spatial variations in the TFs. The SPF and SSCF were most intense in March and October; the KF was most significant in March and May.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.169-177
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• 2002

An eddy-resolving free-surface primitive-equation model with nonlinear terrain-following coordinates is established to study the exchange of water masses among the Asian marginal seas and their adjacent waters. A curvilinear coordinate system is used to generate the horizontal grid with a variable resolution for the regional oceans from $5^{\circ}$S to $45^{\circ}$N and $100^{\circ}$E to $155^{\circ}$E. The higher resolution region has about a 10 km by 10 km grid covering the complex geometry of the coastal marginal seas, while the lower resolution region has about a 30 km by 30 km grid covering the eastern Pacific. The model is initialized by the Levitus annual climitology and forced by the monthly mean air-sea fluxes of momentum, heat, and freshwater derived from the Comprehensive Ocean-Atmosphere Data Set. High-resolution and low-viscosity are identified as the key factors for a better representation of the exchange of waters through narrow straits and passages between the marginal seas and their adjacent waters. The dynamics of the loop currents and eddies in the South China Sea and Celebes Sea are examined in detail. It has found that the anticyclonic loop and detached eddies from the Kuroshio through the Luzon Strait play an important role in transporting warm and salty water into the South China Sea, while the cyclonic circulation of the Mindanao Current in the Celebes Sea plays a role in contributing cold water to the Indonesian throughflow. The deep undercurrent of the western Pacific is shown to provide fresher water to the South China Sea and Celebes Sea. These modeling results suggest that the exchange processes via the narrow straits and passages are of fundamental importance to the maintenance of water masses for the marginal sea region.

• 한국해양학회지
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• 제28권1호
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• pp.24-34
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• 1993

동물플랑크톤의 계절별 분포 특성을 파악하기 위하여 황해 중동부해역을 대상으로 1987년 4월부터 1988년 6월까지 두달 간격으로 조사를 실시하였다. 이 기간중 총 18속 24종의 동물플랑크톤이 동정 되었게, 이중 12속 17종이 요각류였다. 출현한 동물플랑 크톤중 Noctiluca scintillans가 연안역 정점에서 계절에 따라 전체 동물플랑크톤 군 집에 큰 영향을 미쳤으며, 일부 요각류의 분포를 배제하는 것으로 사료되었다. 동물플 랑크톤 출현양의 30-60.4%를 차지하는 요각류 군집 개체수의 계절별 변화양상은 연안 역 정점이 외해역 정점보다 생태환경의 다양함을 보여주었다. 요각류중 Acartia omorii가 4월과 6월에 Paracalanus parvus가 8월부터 12월까지, Corycaeus affinis가 12월에 각각 우점종으로 출현하였다. 난류 지표중인 Sagitta enflata가 8월부터 12월 까지 조사 해역에 출현하여 본 해역에 대한 난류의야 향을 시사하였으며, 이러한 측면 에서 난수성인 Doliolum sp. 의 10월의 다량 출현도 의미있는 결과였다. 동물플랑크톤 에 대한 종조성 및 양적 분포의 계절적 특성은 수괴의 계절적 변화에 따라 영향을 받 는 것으로 나타났다.

• Journal of the korean society of oceanography
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• 제35권4호
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• pp.161-169
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• 2000

A seasonal circulation in the East China Sea and the Yellow Sea and its possible cause have been studied with CSK data during 1965-1989. Water mass distributions are clear in winter, but not in summer because the upper layer waters are quite influenced by atmosphere. To solve the problem, a water mass analysis by mixing ratio is used for the lower layer waters. The results show that the distribution of Tsushima Warm Current Water expands to the Yellow Sea in winter and retreats to the East China Sea in summer. It means that there is a very slow seasonal circulation between the East China Sea and the Yellow Sea: Tsushima Warm Current Water flows into the Yellow Sea in winter and coastal water flows out of the Yellow Sea in summer. By the circulation, the front between Tsushima Warm Current Water and coastal water moves toward the shelf break in summer so that the flow is faster in the deeper region. The process eventually makes the transport in the Korea Strait increase. The Kuroshio does not seem to influence the process. A possible mechanism of the process is the seasonal change of sea surface slope due to different local effects of surface heating and diluting between the East China Sea and the Yellow Sea.

• 한국지구과학회지
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• 제25권1호
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• pp.1-9
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• 2004

The clay minerals of thirty-four bottom sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more-than 70% of whole clay fraction. The highest concentration of illite (>72%) is found in the southeastern offshore parts beyond the reach of terrigenous input from the Cheju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where the fine-grained sediments are discharged from the modern and ancient Huanghe River. The relatively high abundance of kaolinite is likely derived from the Changjiang River via Taiwan ·Warm Current. In contrast, the large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern are, reflecting the transportation by the Huanghai Sea Coastal Current from the southern Yellow Sea.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.696-700
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• 2004

In the Korean seas, Sea Surface Temperature (SST) and Thermal Fronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST. As the result of harmonic analysis, distributions of the mean SST were $10~25^{\circ}C,$ and generally SST decreased as latitude increased. SST increased in the order as following; the South Sea $(20\~23^{\circ}C),$ the East Sea $(17\~19^{\circ}C)$, and the West $Sea(13\~16^{\circ}C).$ Annual amplitudes and phases were $4\~11^{\circ}C,\;210\~240^{\circ}$ and high values were shown as following; the West Sea $(A1,\;9\~11^{\circ}C),$ the Northern East Sea $(A5,\;8\~9^{\circ}C),$ the Southern East Sea $(A4,\;6\~8^{\circ}C),$ the South Sea $(A3,\;6\~7^{\circ}C),$ the East China Sea $(A2,\;4\~7^{\circ}C)$ and phases; $A3\;(238\~242^{\circ}),\;A4\;(235\~240^{\circ}),\;A5\;(225\~235^{\circ}),\;Al\;(220\~230^{\circ}),\;A2\;(210\~235^{\circ}),$ respectively, Both of them were related inversely except the area A2, therefore the rest areas were affected by seasonal variations. TF were detected by Soble Edge Detection Method using gradient of SST. Consequently, TF were divided into 4 fronts; the Subpolar Front (SPF) based on the Cold Water Mass (low SST and salinity Subartic Water), resulting from the North Korea Cold Current (NKCC) and the East Sea Proper Cold Water in the middle and low layer, and the Warm Water Mass (high SST and salinity Subtropical Water), resulting from the Tsushima Warm Current (TWC) in area A4 and 5, the Kuroshio Front (KF) based on the Kuroshio Current (KC) and shelf waters in the East China Sea (ESC) in A2, and the South Sea Coastal Front (SSCF) based on the South Sea Coastal Water (SSCW) and TWC in A3. Also, the Tidal Front was weakly appeared in AI. TF located in steep slope of submarine topography. Annual amplitudes and phases were bounded in the same place, and these results should be considered to influence of seasonal variations.

• 한국환경과학회지
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• 제19권12호
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• pp.1385-1395
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• 2010

Harmful dinoflagellate Cochlodinium polykrikoides blooms have been frequently occurred in coastal areas of the East Sea since 1995. We compared the oceanic conditions in years 1995, 2001 and 2003 when the C. polykrikoides bloom was strong, and in years 1998 and 2004 when the C. polykrikoides bloom was not appeared. We studied temporal and spatial variation of upwelling and geostrophic currents on the western channel of Korean Strait, an entrance of the East Sea. The period and occurrence area of C. polykrikoides bloom was depended on variation of upwelling in summer. In the distributions of geostrophic current, southward current was dominant near the coast in August, 1998 and 2000. Whereas northward current was dominant near and off the coast in August, 1995 and 2003 which the C. polykrikoides bloom was strong. When compared dominant phytoplankton of the coastal areas in each year, Kuroshio indicator species Proboscia alata and Chaetoceros affine were dominant, respectively, in 2001 and 2003 at every stations. However, the dominant species was variable at each coastal area in 1998 and 2000. In 2003, the abundance of Sagitta elegans which is known as the cold water indicator was low, but the abundance of S. enflata, warm water indicator, was very high in Gangneung compared to Sokcho. It seemed that the distribution of S. elegans is restricted by strong warm water current. In conclusion, it was estimated that the distribution of C. polykrikoides bloom in the coastal area of the East Sea was closely related with the strength of East Korea Warm Current and upwelling.

• 수산해양기술연구
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• 제26권2호
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• pp.184-191
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• 1990

하계 대한해협 서수도에는 연직적으로 특성이 서로 다른 세 개의 수괴가 존재한다. 그 중 표층수에 대하여 인접 해역의 해수 특성과 상호 비교함으로써 그 기원과 유로를 추정하였다. 그 결과, 표층수는 동지나해의 대륙붕 상에서 형성된 Kuroshio수와 중국대륙연안수의 혼합수로써, 중국대륙연안수의 영향을 더 많이 받는 것으로 나타났다. 대부분의 표층수는 Kyushu Island의 서쪽 해역, 경도 126$^{\circ}$E와 127$^{\circ}$E 사이 해역과 제주도 동쪽 해역을 거쳐 유입되고, 한국 연안 부근에 있는 일부 표층수는 제주도 서쪽해협을 거쳐 유입된 것으로 나타났다.