• Ocean and Polar Research
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• 제35권3호
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• pp.259-272
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• 2013

One of the factors influencing the climate around Korea is the oceanic-atmospheric variability in the tropical region between the eastern Indian and the western Pacific Oceans. Lack of knowledge about the air-sea interaction in the tropical Indo-Pacific region continues to make it problematic forecasting the ocean climate in the East Asia. The 'Tropical Indo-Pacific water transport and ecosystem monitoring EXperiment (TIPEX)' is a program for monitoring the ocean circulation variability between Pacific and Indian Oceans and for improving the accuracy of future climate forecasting. The main goal of the TIPEX program is to quantify the climate and ocean circulation change between the Indian and the Pacific Oceans. The contents of the program are 1) to observe the mixing process of different water masses and water transport in the eastern Indian and the western Pacific, 2) to understand the large-scale oceanic-climatic variation including El Nino-Southern Oscillation (ENSO)/Warm Pool/Pacific Decadal Oscillation (PDO)/Indian Ocean Dipole (IOD), and 3) to monitor the biogeochemical processes, material flux, and biological changes due to the climate change. In order to effectively carry out the monitoring program, close international cooperation and the proper co-work sharing of tasks between China, Japan, Indonesia, and India as well as USA is required.

• 수산해양기술연구
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• 제48권3호
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• pp.217-226
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• 2012

Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

• Ocean and Polar Research
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• 제24권1호
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• pp.19-31
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• 2002

Precipitation variability around King Sejong Station related with E1 $Ni\~{n}o$/Southern Oscillation (ENSO) is evaluated using the gauge-based monthly data of its neighboring stations. Though three Ant-arctic Stations of King Sejong (Korea), Frei (Chile), and Artigas (Uruguay) are all closely located within 10 km, their precipitation data show mostly insignificant positive or rather negative correlations among them in the annual, seasonal and monthly precipitation. This result indicates that there are locally large variations in the distribution of precipitation around King Sejong Station. The monthly data of Frei Station for 31 years (1970-2000) are analyzed for examining the ENSO signal in precipitation because of its longer precipitation record compared to other two stations. From the analysis of seasonal precipitation, it is seen that there is a tendency of less precipitation than the average during E1 $Ni\~{n}o$ events. This dryness is more distinct in fall to spring seasons, in which the precipitation decreases down to about 30% of seasonal mean precipitation. However, the precipitation signal related with La $Ni\~{n}a$ events is not significant. From the analysis of monthly precipitation, it is found that there is a strong negative correlation during 1980s and in the late 1990s, and a weak positive correlation in the early 1990s between normalized monthly precipitation at Frei Station and Sea Surface Temperature (SST) anomalies in the $Ni\~{n}o$ 3.4 region. However, this relation may be not applied over the region around King Sejong Station, but at only one station, Frei.

• 수산해양기술연구
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• 제51권4호
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• pp.553-560
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• 2015

The feeding habits of the Pacific bluefin tuna, Thunnus orientalis were examined based on the stomach contents of 330 specimens caught by offshore large purse seine fishery in the southern sea of Korea, 2011. The size of Pacific bluefin tuna used in this study ranged from 34.1 to 67.3 cm in fork length (FL). The percentage of empty stomachs was 41.8%. The main prey items were Pisces and Cephalopoda based on percentage IRI (index of relative importance). The main fish preys were Trachurus japonicus, Bregmaceros japonicus, Engraulis japonicus, and Cephalopoda were Todarodes pacificus, Loligo edulis, Watasenia scintillans. T. orientalis showed ontogenetic change in diet composition. Although Pisces dominated the diet of all length classes the portion of Cephalopoda was relatively higher in size between 40 and 50 cm other than length classes. In terms of seasonal variation in feeding habits, Pisces was the main prey group in all seasons, but Cephalopoda was also frequently consumed during spring and autumn based on %IRI.

• 수산해양기술연구
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• 제17권2호
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• pp.65-69
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• 1981

우리나라 남부해안기후의 특성과 수온과의 관계를 알아보기 위하여 해안지방인 부산, 여수, 목포를 준표준 내륙지방으로 광주와 대구, 인근 해양의 가덕도, 소리도, 홍도의 수온을 선정하여 20년 간(1960~1979)의 관측자료로서 기온, 습도, 강수량을 조사 분석한 결과는 다음과 같다. 1) 해안지방(부산, 여수, 목포)은 해양의 영향으로 내륙지방(대구, 광주)보다 기온의 연교차가 적고 기온이 수온보다 높을 때는 내륙지방이 해안지방의 기온보다 높고, 수온이 기온보다 높을 때는 내륙지방이 해안지방보다 낮다. 2) 수온과 기온의 차에 따라서 내륙지방과 해안지방의 기온차가 결정되며(상관계수 0.9이상) 그 양적 예측도 상관관계식을 활용함으로써 가능하다고 생각된다. 3) 해안지방과 내륙지방의 습도의 차이도 기온의 경우와 비슷하게 나타났으나 목포는 지형적인 영향으로 다른 해안지방과 다르게 나타났다. 4) 수온과 기온의 차이에 따라서 해안지방과 내륙지방의 습도의 차이가 결정된다(상관계수 0.9이상, 목포제외), 그러므로 그 양적 해석도 가능하다. 5) 남해안지방의 강수량은 내륙지방과 그 차이가 뚜렷하게 나타나지는 않았다.

• 한국해양공학회지
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• 제22권2호
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• pp.28-33
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• 2008

From the 1997 to January, 2004, a groin 156m long was constructed at the mouth of the Heoya river-mouth as a protection and barrier. To understand the changes to Jinha beach from the blockade of the river mouth, several aerial photographs, etc., were compared, which showed that the changes were significant. Comparing these results to the state of the area before construction of the groin, the blockade of the river was relaxed, but the formation of the tombolo, in the middle groin area was accelerated and the total Jinha beach erosion and especially the erosion of the southern part of Jinha beach was developed. But according to statements by residents and some current documents, the blockade of the Heoya-river mouth is still underway at the surrounding areas of the groin and chronic dredged sand has been used for littoral nourishment at the northern part of the middle groin and on Jinha beach. The result of numerical simulation based on the present state shows that if this sort of dredging is stopped, the sand accumulation will progress near the river mouth groin and the existing tombolo at the middle groin will progress to the north and severe erosion will occur at the southern coastline near the middle groin and the farthest southern part of Jinha beach, and Jinha beach itself will experience a gradual erosion. The main reason for these erosions should be the typhoons that are happening during the summer season. To provide protection from these kinds of undesirable erosions, a total of 23 numerical simulations have been done. It has been shown that submerged breakwaters at the front area of the beach will be efficient to protect from main beach erosion, but there should be alternative proposals for the influence of the river mouth blockade.

• Ocean and Polar Research
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• 제41권3호
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• pp.135-145
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• 2019

We investigated the mass occurrence of the salp Salpa fusiformis during spring in the southern waters of Korea and the northern East China Sea. Abundance of S. fusiformis and dominant taxonomic groups including copepods, ostracods, euphausiids, and appendicularian was examined along with environmental factors (e.g., temperature, salinity, and chlorophyll-a concentration). The abundance of S. fusiformis at 27 stations ranged from 0 to $183\;inds\;m^{-3}$. Both aggregate and solitary forms of S. fusiformis occurred with a mean abundance of $62\;inds\;m^{-3}$ and $4\;inds\;m^{-3}$, and mean body length of 6.5 mm and 15.4 mm, respectively. Redundancy analysis showed that the abundance of S. fusiformis was negatively correlated with chlorophyll-a concentration, indicating the intensive grazing impact of S. fusiformis on phytoplankton. While the abundance of S. fusiformis increased, the species diversity of zooplankton community decreased. The abundances of total copepods and the dominant copepod species (e.g., adults and/or copepodites of Paracalansus parvus s.l., Calanus sinicus, Oithona similis, and Corycaeus affinis) also decreased with the increase of S. fusiformis abundance. However, the abundance of ostracods, euphausiids, and appendicularians was not affected by the mass occurrence of the salps. These results suggest that the mass occurrence of S. fusiformis in spring could negatively affect ecosystem conditions by changing trophodynamics in the zooplankton community.

• 한국환경과학회지
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• 제30권12호
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• pp.1067-1079
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• 2021

The coastal water is a space where salmon (Oncorhynchus keta), critical energy-conveying mediator, stay to adapt to different environments while traveling between ocean and river ecosystems for spawning and growth. The mid-eastern coast of Korea (MECW) is the southern limit of salmon distributed in the North Pacific Ocean. Understanding the distribution and migration characteristics of salmon in the MECW is important for the prediction of changes in the amount and distribution of salmon related to changes in the future marine environment. We analyzed the relationship between the salmon migratory timing ascending the Wangpi river and change in vertical seawater temperature and tidal elevation. Overall results highlight that (1) Salmon began to ascend the river when the sea surface water temperature (SST) decreased below 20℃; (2) The number of salmon ascending the river increased when the temperature difference between the upper and lower layers decreased, but decreased when the temperature difference was higher than 5℃; (3) The number of salmon ascending the river peaked, when the SST was 18℃-19℃ and sea levels rose at high tide. This study provide important insight into predicting changes in the ecosystem energy circulation through climate change at its southern distribution limit.

• 자원환경지질
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• 제50권6호
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• pp.477-486
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• 2017

본 연구에서는 독도, 동도와 서도 연안에서 정밀 해저 지형과 해저면 영상 자료를 획득하여 해수면 아래에서 나타나는 해저 지형 및 해저면 환경 특성을 비교 분석하였다. 독도 섬 육지부와 바로 연장되는 동도와 서도 각 남부 연안 해역의 약 $250m{\times}250m$ 범위에서 정밀 수심 자료와 해저면 영상 자료를 획득하였다. 동도 남부 연안은 최대 수심 약 50 m 범위이며, 서도 남부 연안은 최대 수심 약 30 m 범위에 해당한다. 동도와 서도 연안은 섬 육지부에서부터 연장되는 모암이 해수면 아래로 그대로 이어져 해저면에서 큰 수중 암반 지대를 형성하고 있는데, 그 규모는 서도 남부 연안이 동도 연안에 비해 비교적 크게 나타난다. 동도와 서도 연안 모두 유사한 수중 암반 지대가 형성되어 있지만, 주변으로 형성된 해저면 환경은 동도와 서도 남부 연안에서 상이하게 나타나는 특징을 보이고 있다. 동도 남부 연안은 섬 육지부에서 기인한 크고 작은 암설들로 인해 형성된 테일러스(Talus) 형태의 해저면 환경이 수심 약 15 m 범위까지 형성된 특징을 보이며, 수중 암반 지대와 해저면의 경계면이 모호하게 형성되어 있다. 반면에 서도 남부 연안은 비교적 큰 규모의 수중 암반들과 고른 퇴적물이 분포하여 해저면과 접하고 있는 섬 육지부터 연장되는 암반들의 경계면이 확실하게 구분되는 특징을 보이고 있다. 이는 동도의 해안 절벽에 많이 노출되어 있는 응회암층이 풍화나 침식에 약하여, 서도 연안에 비해 섬 육지부로부터 운반된 쇄설성 퇴적물이 흘러내린 영향이 많은 것으로 판단되는데, 특히 동도는 서도에 비해 선착장이나 통행로 개설공사 등의 활동이 계속되어 섬 육지부의 지반 불안정과 단층, 절리, 균열이 높은 편으로 나타난 바 있다. 또한 과거 연구 결과들에서 동도와 서도에 나타나는 괴상 응회질 각력암층이 서로 다르게 형성되어 있음이 제시된 바 있는데, 이러한 요소가 동도와 서도 남부 연안 해저면에서 구별되어 나타나는 쇄설성 퇴적물 환경에 영향을 주었을 것으로 판단되며, 동도와 서도 남부 연안의 상이한 해저면 환경적 특성이 나타나는 것으로 생각된다.

• 한국해양학회지:바다
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• 제5권4호
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• pp.320-334
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• 2000

북동 태평양의 위도별(131$^{\circ}$30'W, 5${\sim}$12$^{\circ}$N) 각 지점에서 다중 주상시료 채취기(multiple corer)로 획득된 31개 표층 퇴적물의 지질공학적 특성을 분석하였다 환경연구지역을 포함한 연구지역 북부(9${\sim}$12$^{\circ}$N)퇴적물은 대부분 규질퇴적상을 보인다. 반면 남쪽지역(5${\sim}$6$^{\circ}$N)에서는 탄산질 퇴적물이 산출되는데, 이는 수층 생산성이 높고 이 지역 탄산염 보상심도(CCD: 4,400 m)보다 수심이 얕은데 기인된 결과이다. 지질공학적 특성은 7$^{\circ}$N을 경계로 남-북 퇴적물간 뚜렷한 차이를 보인다. 남쪽지역의 탄산질 퇴적물은 낮은 함수율, 공극율, 전단강도, 그리고 높은 입자 밀도 및 전밀도의 원인이 된다. 반면에 망간단괴가 고밀도로 분포하고 있는 북쪽지역 퇴적물은 주로 생물기원 규질 퇴적물로 구성되어 있으며, 이는 높은 함수율, 공극율, 전단강도 그리고 낮은 입자 밀도 및 전밀도의 일반적 원인이 된다. 퇴적물의 활성도(activity)는 북쪽 퇴적물에서 매우 높게 나타난다. 한편, 북쪽지역 퇴적물들은 표층에서 약 5${\sim}$8 cm를 경계로 준액상(semi-liquid)인 상부층과 단단하게 굳어진 하부층으로 뚜렷이 구분되며, 깊이에 따라 급격한 지질공학적 특성 변화를 보인다. 반면 남쪽 지역에서는 이러한 깊이에 따른 지질공학적 특성 변화가 적다. 이러한 남-북 지역 퇴적물중 지질공학적 특성의 위도별, 깊이별 변화는 탄산질 퇴적물과 규질 퇴적물의 분포, 수층의 생산성 및 수심변화에 따른 용해도와 퇴적을 차이 그리고 침식 및 재퇴적작용 등 퇴적 과정이 위도별로 달랐기 때문으로 판단된다.