• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 춘계학술대회 논문집
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• pp.91-94
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• 2006

중국 대륙연안수(CCW;China Coastal Waters)는 해에 따라 다소 다르지만 보통 하계인 6월$\sim$10월 사이에 제주도 주변해역에서 두드러지게 나타난다. 즉, 5월에 나타나기 시작하여 8월에 가장 큰 영향을 미치며 10월로 접어들면서 그 세력이 점차 소멸해간다. 해수면편차와 해수면온도의 경험직교함수 분석 결과 해수면편차는 $1{\sim}3$모드가 총 분산의 95.05%를 차지하였고, 해수면온도는 1모드가 총 분산의 98.70%를 차지하였다. 해수면편차 경험직교함수분석의 첫 번째 결과에 대한 파워스펙트럼분석에서는 중국대륙연안수에 의한 영향으로 동쪽해역보다 서쪽해역이 43일 주기의 세력이 더 강하게 나타났다. 해수면온도에 대해서는 양자강 하구를 비롯한 제주도 동쪽 서쪽해역의 주기가 모두 260일 주기가 나타남으로서 중국대륙연안수는 43일, 120일 등의 짧은 주기 보다는 비교적 장주기라 할 수 있는 260일 주기에 더 큰 영향을 미쳤다.

• Journal of information and communication convergence engineering
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• 제7권4호
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• pp.580-585
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• 2009

Harmful Algal Blooms (HABs), caused by Cochlodinium polykrikoides that causative fishery mortality, impact on aquaculture and economic loss appear particularly in summer and fall seasons in the Korean seas. It was studied on characteristics of HABs in the South Sea of Korea by using satellite and in-situ data. The in-situ data encompassed oceanic and meteorological data from July to October 2002-2008 and satellite data from July to October 2002-2006. Chlorophyll concentrations were calculated using Seaviewing Wide Field-of-view Sensor images by an Ocean Color (OC4) algorithm, and HABs were estimated using the Red tide index Chlorophyll Algorithm (RCA). The HAB occurrences were dominant when water temperature was $22.6-28^{\circ}C$ in August. The frequency of the individual numbers during 2002-2008, the HABs more than 1000 cells/ml (alert condition), were 73.57 %. In meteorological data from July to September during 2002-2008, the average precipitation, the mean air temperature, the mean wind speed and direction, and the sunshine were 9.31 mm/day, $24.07^{\circ}C$, 2.34 m/s and easterly, and 1-11 h, respectively. Our results suggest that the upwelling is caused by southwesterly wind in summer season and the Tsushima Warm Current which have influenced on the dispersion and moving of HAB (chlorophyll). In addition, the fresh water from Nakdong River, as the source of nutrients, also influences the occurrence of HABs.

• 한국환경과학회지
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• 제22권10호
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• pp.1363-1371
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• 2013

In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the $15^{\circ}C$ thermal front moves in the north-south direction according to the movement of the warm water (above $18^{\circ}C$) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below $10^{\circ}C$) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of $6^{\circ}C$ are consistent with the east-west zonal areas in the central East Sea which represented over $1^{\circ}C$ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-$22^{\circ}C$, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.

• 한국수산과학회지
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• 제15권4호
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• pp.255-262
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• 1982

1. 일반적으로 제주도 연안역에서의 영양염류 농도는 성분에 따라 차이가 있으나 표층보다 50 m이심에서의 농도가 $0.5\sim3$배 정도 높다. 2. 제주도 남동쪽 해역의 수온, 염분과 규산염, 질산염, 인산염, 용존산소의 농도 분포가 단조롭고 비교적 각 성분의 량도 적다. 3. 제주도 북쪽 해역은 한국남안연 안수의 영향을 받아 각 성분의 농도 분포가 복잡하고 그 변동 범위도 크다. 또 영양염류도 이 해역이 남동쪽 해역보다 풍부하다. 4. 제주도 남서쪽 해역은 황해저층냉수의 영향을 받아 영양염이 풍부하나 황해난류와 만나는 호경역이므로 그 분포상은 매우 복잡하다.

• 한국수산과학회지
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• 제40권3호
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• pp.160-166
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• 2007

The coarse deposit with a lower mud content adjacent to the shelf of the southern East Sea is probably a "relict" sediment deposited in response to a lower stand of sea level during the Pleistocene. The sediment that developed on the slope and in the deep sea was river-borne primarily and was secondarily reworked or redistributed by the Tsushima Warm Current from the East China Sea. The clay mineralogy of the area suggests various sources of fine-grained sediment from adjacent rivers, the Korea Strait, volcanic material from Ulleung Island, and the Japan coast. Massive sand, bioturbated mud, homogeneous mud, and laminated mud were the dominant facies found in the core sediments from the study area. The massive sand was mainly volcanic ash from an eruption on Ulleung Island (9300 yr BP) and consisted of colorless pumiceous glass and a black scoriaceous type. The sedimentation rates on the slope, based on the Ulleung-Oki ash layer, were about 10cm/ky higher than in the basin. Other than the coarse-grain sediment, the mean size of the fine sediment dominating the bioturbated and homogeneous muds in the basin and the laminated mud on the slope was 6-10 phi. This indicates a difference in the major sedimentary process: hemipelagic sedimentation in the Ulleung Basin and mass flow deposition, such as turbidite, on the slope of the southern East Sea.

• 한국수산과학회지
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• 제50권2호
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• pp.183-194
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• 2017

The catch of Todarodes pacificus in the Yellow Sea is commonly known as the winter cohort. So, to understand the transport process of winter cohort of T. pacificus, and to identify whether the simulated individuals which are transported directly into the Yellow Sea (YS) influence these resources immediately, we conducted a Lagrangian-particle-tracking numerical experiments of T. pacificus from 2005 to 2010 using LTRANS and ROMS. The results show that: (1) Most of the released individuals spread out to the open sea by the Kuroshio and the Tsushima Warm Current around 30 days after release. (2) Unlike the hypothesis proposed by Rosa et al. (2011), Around $30-33N^{\circ}$ near Jeju Island simulated the initial position (3) About 0.01% of individuals released in December were transported solely into the YS around 15 days after release. However there were no surviving individuals due to the low temperature less than $12^{\circ}C$. Also the variation of individuals entered into the YS was not significantly correlated with it in YS catches during the experimental period. Therefore, the most of resources in the YS is assumed to be more influenced by diverse factors of the Pacific Ocean and East Sea than the direct transport in the YS of winter cohort.

• 한국해양학회지
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• 제21권3호
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• pp.146-155
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• 1986

1984년 5월 50m수층과 1985년 10월 수온구조에 따른 여러 층에서 채집한 동 물플랑크톤 시료를 분석한 결과, 현존량은 춘계에 평균 538 inds/㎥, 추계에는 전 수층 평균과 표층이 각기 267inds/㎥와 508inds/㎥ 를 나타낸다. 양 계절에 동정된 분류군은 각기 55종류, 104종류였으며 연구해역의 서식 분류군은 123종류에 이른다. 동물플랑크톤 군집에서의 우점종의 순위는 양 계절 공히 copepods를 필두로 protozoans, appendicularians 이다. 표층에서의 아열대성 종과 현존량의 분포는 동 계에 있어 대마해류 및 북한한류수의 영향을 반영하는 것으로 사료되는 반면, 춘계 에는 현존량만이 식별할 수 있는 변화를 보인다. 1985년 추계에는 전 수층에 걸쳐 영구 수온약층의 저부인 120m 수심이 중층 냉수종의 분포에 대한 장벽으로서 중요 한 역할을 한다. 1985년 10월에 연속 채집한 시료의 분석결과, 식별할 수 있는 주야 수직이동은 나타나지 않는데, 이는 동물플랑크톤 가운데 진정한 심해종의 결핍으로 심층에서의 생체량이 아주 빈곤하고 따라서 동해에서의 수직이동이 미약하다는 이 론을 입증하는 것으로 사료된다.

• Animal Systematics, Evolution and Diversity
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• 제28권4호
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• pp.279-290
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• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.

• 한국수산과학회지
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• 제44권3호
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• pp.267-275
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• 2011

The common squid Todarodes pacificus is an ecologically and commercially important species in Korea and Japan. However, the distribution pattern of its eggs and larvae in Korean waters has not yet been clarified. To determine the horizontal and temporal distribution of common squid larvae in the northern East China Sea, samples collected using paired, 60 cm diameter Bongo nets from the three surveys conducted in August 2003, May 2004 and November 2005 were examined. In addition, the vertical distribution was examined from the samples collected using a $1\;m^2$ MOCNESS in April 1999 (20 m interval down to 100 m). A total of 218 larvae ranging in mantle length (ML) from 1.2 to 17.0 mm were counted at 27 stations. Larval abundance was highest in May 2004. The larvae mainly occurred in the southeastern area of Jeju Island, where the water temperature and salinity at 50 m deep ranged from $15-23^{\circ}C$ and 34-34.6 psu, respectively. Most larvae were collected in the frontal zone, where the Tsushima Warm Current and inshore waters meet. The results from the MOCNESS samples showed that the larvae occurred mostly in 20-80 m depth ranges (about 90%), although collections were only conducted above 100 m. No significant differences in larval mantle lengths (ANOVA, P>0.05) were found among each depth interval. Given the occurrence sites of the larvae <2.0 mm ML, the spawning ground of this species appears to be within the northern East China Sea, mainly to the southeast and northeast of Jeju Island, in early spring.

• Ocean and Polar Research
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• 제31권1호
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• pp.11-29
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• 2009

Variability of sea surface temperature (SST) in the Japan/East Sea (JES) was studied using complex empirical orthogonal function (CEOF) analysis. Two daily data sets were analyzed: (1) New Generation 0.05o-gridded SST from Tohoku University, Japan (July 2002-July 2006), and (2) 0.25o-gridded SST from the Japan Meteorological Agency (October 1993-November 2006). Linkages with wind stress curl were revealed using 6-h 1o-gridded surface zonal and meridional winds from ancillary data of the Sea- WiFS Project, a special National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) product (1998-2005). SST anomalies (SSTA) were obtained by removing the seasonal signal, estimated as the leading mode of the CEOF decomposition of the original SST. Leading CEOF modes of residual SSTA obtained from both data sets were consistent with each other and were characterized by annual, semiannual, and quasi-biennial time scales estimated with 95% statistical significance. The Semiannual Mode lagged 2 months behind the increased occurrence of the anticyclonic (AC) wind stress curl over the JES. Links to dynamic processes were investigated by numerical simulations using an oceanic model. The suggested dynamic forcings of SSTA are the inflow of subtropical water into the JES through the Korea Strait, divergence in the surface layer induced by Ekman suction, meridional shifts of the Subarctic Front in the western JES, AC eddy formation, and wind-driven strengthening/weakening of large-scale currents. Events of west-east SSTA movement were identified in July-September. The SSTA moved from the northeastern JES towards the continental coast along the path of the westward branch of the Tsushima Current at a speed consistent with the advective scale.