• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.5-20
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• 2002

To investigate the effect of mechanical parameters on the circulation and its fluctuation in Sagami Bay, baroclinic model experiments were carried out by use of a two-layer source-sink flow in a rotating tank. In the experiment, a simple coastal topography with flat bottom was reproduced. The results show that the path of the Through Flow, which corresponds to the branch current of the Kuroshio, depends on external Rossby number (Ro) and internal Rossby number $(Ro^*)$, and divided into two regimes. For $Ro^*\leq1.0$ in which Rossby internal radius of deformation of the Through Flow is smaller than the width of the approaching channel, the current flows along the Oshima Island as a coastal boundary density current separated from the western boundary of the channel. For $Ro^*>1.0$ it changes to a jet flow along the western boundary of the channel, separated from the coast of Oshima Island. The current is independent on both Ro and Ro* in the regime of $Ro^*>1.0,\;Ro\geq0.06$ and $Ro^*\leq1.0,\;Ro\geq0.06$. The pattern of the cyclonic circulation in the inner part of the bay is also determined by Ro and Ro*. In case of $Ro^*\leq1.0$, frontal eddies are formed in the northern boundary of the Through Flow. These frontal eddies intrude into the inner part along the eastern boundary of the bay providing vorticity to form and maintain the inner cyclonic circulation. For $Ro^*>1.0$, the wakes from the Izu peninsula are superposed intensifying the cyclonic circulation. The pattern of the cyclonic circulation is divided into three types; 1) weak cyclonic circulation and the inner anticyclonic circulation $(Ro<0.12)$. 2) cyclonic circulation in the bay $(0.12\leq Ro<0.25)$. 3) cyclonic circulation with strong boundary current $(RO\geq0.25)$.

• 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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• 제28권2호
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• pp.101-106
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• 1993

하계에 나타나는 황해저층내수에 간단한 3차원의 육면체 모델을 적용하여, 조석의 혼합작용과 쿠로시오수괴가 황해저층냉수의 형성에 주는 영향을 연구하였다. 본연구에 서는 수치모델의 기술적인 문제 때문에 조석의 혼합작용을 연직혼합계수로 매계변수화 하였다. 또한 연안을 따라 나타나는 수온전선은 조석의 혼합작용에 의해서 형성되도록 하였으며, 황해저층냉수의 남부에 나타나는 수온전선의 형성에는 고온의 쿠로시오수괴 를 고려하였다. 수치실험의 결과, 모델의 상층과 하층에서 수온분포의 영향이 반대로 나타났다. 상층에서는 모델의 중앙부에서, 하층에서는 연안해역에서 각각 상대적으로 고온의 수온분포가 나타났다. 해수의 순환형태 역시 상층과 하층 사이에 반대로서, 상 층에는 시계방향이, 하층에는 반시계방향의 순환이 나타났다.

• 한국해양학회지
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• 제30권3호
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• pp.203-215
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• 1995

1983년 4월과 5월에 걸쳐 제주해협에서 부표와 해류계를 이용한 해류관측과 함께 2회에 걸쳐 수온-염분관측을 실시하였다. 관측자료로부터 고온, 고염인 흑조 의 한 지류가 제주도 서쪽을 돌아 제주해협으로 유입됨을 명확히 보였다. 제주도 서쪽을 우회하는 해류는 제주도 서쪽에서는 그 폭이 약 60 km이며 제주 해협내 에서는 20∼30 km 이내에 존재하여 제주도 서쪽에서는 5 cm/s 미만으로 유속이 작은 반면에 제주해협의 서쪽입구와 해협 내에서는 10 cm/s 이상의 큰 유속을 갖는다. 제주해협의 동쪽에는 역시 흑조로부터 기원된 대마난류의 영향이 인지 되었다. 난류수와 연안수 사이에 형성되는 수온, 염분전선의 변화는 제주 해협의 서쪽에서 황해연안수가 남하함을 제시하였다. 난류수역에서는 5월에 수온이 상승 한 반면에 다른 해역에서는 수온이 감소하였다. 5월에 제주해협 중앙부에서는 해 협의 서쪽으로부터 저온, 저염의 해수가 유입되어 4월에 비해 수온과 염분이 급격 히 감소하였다.

• 한국수산과학회지
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• 제38권1호
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• pp.29-38
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• 2005

The distributions of fish larvae and juveniles from the East China Sea, Yellow Sea and near Tsushima Island were investigated in Spring using the Maruchi (1994-1995) and Unagi (1996-1997) nets. A total of 94 species of fish larvae and juveniles belonging to 49 families under 17 orders were identified, of which Engraulis japonicus was dominant in every year except 1995 where Trachurus japonicus was dominant. Cluster analysis based on abundance and species composition by sampling stations (St.) revealed that the similar stations formed an arcuate group from Tsushima Island to southern Jeju Island in 1994, and from the Yellow Sea to southern Jeju Island in 1996. We concluded that these patterns resulted from the influence of the Tsushima Current prevailing in the east, and the Chinese Continental Waters and/or Hwanghae Cold Waters prevailing in the west, with Jeju Island exerting an influence in the centre. The diversity and composition of St. 97-3 and St. 97-5, both located where the Tsushima Current splits from the Kuroshio Current, was greatly different despite their close proximity. However, the former is located on the continental shelf, with the latter on the continental slope. This suggested that both topography and the Kuroshio Current have the most influence on the distribution of fish larvae and juveniles in this region. Furthermore, the weak Hwanghae Cold Waters of 1997 may have also limited the mixing of fish larvae and juveniles between the two stations.

• 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.

• 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.

• 한국해양학회지
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• 제1권1_2호
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• pp.14-21
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• 1966

우리 나라의 서, 남, 동해 즉 황해, 한국해협 및 일본해는 각자가 특이한 해양학적 구조를 지니고 있다. 서해는 전반적으로 80m이천의 천해를 구성하여 대륙계 하천수를 풍부하게 공급을 받아, 계절풍이 심한 추, 동계에는 특이 부니질의 발달이 현저하고, 이곳의 해양수는 대륙의 기후의 영향을 많이 받고 있는 것이 특징이다. 한편 일부의 황해수는 황해나뭅, 동지나해에서 이류에 의해 흑조와 혼합되어 대마난류를 형성하여 한국해협을 거쳐 일본해로 유입한다.

• Journal of Ecology and Environment
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• 제30권1호
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• pp.23-38
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• 2007

Based on a time series of ocean climate indices and catch records for seven pelagic fish species in the Tsushima Warm Current (TWC) and Kuroshio-Oyashio Current (KOC) regions from 1910 to 2004, we detected regional synchrony in the long-term fluctuations of the fish populations and identified alternation patterns of dominant species related to climate shifts. The annual catches of Pacific herring, Japanese sardines, Japanese anchovies, jack mackerel, chub mackerel, Pacific saury and common squid in the TWC region fluctuated in phase with those in the KOC region, which suggests that they were controlled by the same basin-wide climate forcing. After the collapse of the herring fishery, the alternation sequence was: sardines (1930s), Pacific saury, jack mackerel, common squid and anchovies ($1950s{\sim}1960s$), herring ($late\;1960s{\sim}early\;1970s$), chub mackerel (1970s) and then sardines (1980s). As sardine biomass decreased in the late stages of the cool regime, catch of the other four species increased immediately during the warm period of the 1990s. Regional differences in the amplitude of long-term catch fluctuations for the seven pelagic fishes could be explained by regional differences in availability, fishing techniques and activity.

• 수산해양교육연구
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• 제17권1호
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• pp.58-66
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• 2005

Floating debris was observed using a training ship, KAYA, of Pukyong National University with cruising speed of about 10-12 knot during July 12~25, 2003. The area sampled was the East Sea enclosed by 3 nations, namely, Korea, Japan and Russia, and was divided into 68 unit segments on survey routes [Fig. 1]. Debris fabrication materials were categorized with 6 items, e.g., man-made or natural wood items, paper and cardboard, nylon rope, styrofoam, vinyl and plastic, floating metal and glass containers. All identified items within $100{\pm}10 m$ wide band were recorded but ignored if beyond this boundary. The results of this study are as follows: 1. The average numbers of debris per unit area, $1km^2$, were found as 16.3 pieces (items) in the sea. 2. The highest densities of numbers, $32.3pieces/km^2$, were discovered in vicinity of the Oki strait of Japan, area of 'NEK' in Fig. 1. 3. Especially, styrofoam item only was composed to 63.6% of all in the sea of 'SD', located in the southern part of Dokdo Island, Korea. The item seems to be derive from the Southern Sea of Korea. 4. Therefore, comparing the distribution of debris numbers (the results of above 2 and 3) with flow patterns of Kuroshio currents, it was shown that their relation was good agree each other. Further more surveys are being conducted and a much wider coverage can be achieved with other countries, then it can be obtained that the East Sea is polluted to some extent, where is the origin of debris, and the finding of floating routes and stationary sea.