• 한국수산과학회지
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• 제11권2호
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• pp.49-54
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• 1978

한국 동해안해역에서 하계에 출현하는 냉수괴의 생성기구를 해양화학적인 측면에서 검토한 결과를 요약하면 다음과 같다. 1. 동해연안의 냉수괴출현해역의 인산염과 용존산계의 특수한 관계를 조사한 결과 동해남부 연안해역인 감포부근 해역에서만 용승현상을 인정할 수 있었으나 그 이북 동해중부해역에서는 용승현상을 인정할 수 없었다. 2. $\sigma_t-O_2$ diagram에 의해 동해연안해역의 구성수괴를 분석하면 T-S diagram 으로는 구별하기 어려운 북한한류계수와 일본해고유냉수를 구별할 수 있었다. 3. 동해남부 연안해역을 제외한 동해중부 연안해역에 출현하는 냉수괴의 기원은 일본해고유냉수의 용승에 의한 것이 아니고, 북한한류가 안안을 따라 남하하는 현상 때문으로 보인다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.57-60
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• 2008

The flow of freshwater into the sea, termed as submarine groundwater discharge, is a key factor for understanding the hydrological cycle in both the sea and land regions. The numerous positions from which freshwater gushes out or its quantity impedes the understanding of its properties. Therefore, this study detects groundwater discharge points arising due to the difference in freshwater and seawater by using the multispectral Landsat ETM+ signals. A case study in coastal regions around Mt. Chokaisan, Japan is performed. This study comprises three procedures: (1) computer simulation of the flow of submarine groundwater discharge in the study area, (2) performance of preliminary experiment on the band properties of the Landsat ETM+, (3) detection of the difference in water properties by using the Landsat multispectral bands. Our experimental results obtained by the Landsat ETM+ are in considerable agreement with the realities in the study area.

• Ocean and Polar Research
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• 제34권4호
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• pp.403-411
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• 2012

Among others, a question that has long been unanswered is why the seasonal variation of volume transport is larger in the Soya and Korea/Tsushima Straits than in the Tsugaru Strait. An attempt is made to answer this question in terms of the island rule with friction being taken into account. The problem is idealized as a simple model. The model results indicate that volume transport through a channel is determined not only by the circulation created around the adjacent island but also by those created around the neighboring islands farther away. The latter is due to the presence of bottom friction in the channels. The volume transports through the Korea/Tsushima, Tsugaru and Soya Straits estimated from the model using observed wind data show the general pattern of observed seasonality, although they contain large errors associated with the uncertain frictional parameter employed in the model. The model indicates that the observed seasonality arises essentially from the fact that wind stress curl changes its sign, from negative in the summer to positive in winter, following a large fluctuation of zero-stress curl latitude east of Hokkaido.

• 한국해양공학회지
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• 제16권1호
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• pp.16-22
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• 2002

The diffusion characteristics of an ocean dumping material in the south-eastern East/Japan Sea related to regulate the physical characteristics with the observation and the hydraulic experiment are investigated. The main results are as follows; (1) Spying CTD observation result of the area of Jung in the East/Japan Sea, the ocean dumping area had influenced the Tsushima Warm Current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913$\times$10$^{7}$ by drogue tracking. (2) From the experiment of settling, the initial settling velocity of each material is 1.0~2.7 cm/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffusion must be regard the pynocline in the ocean area have well-developed pycnocline. (3) Vertical turbulent diffusivity were 2.219$\times$10$^{-8}$ ~8.874$\times$10$^{-4}$ cm$^2$/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity.

• Ocean Science Journal
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• 제43권1호
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• pp.39-48
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• 2008

Tritium ($^3H$ or T) has been produced mostly by atmospheric nuclear weapon tests, and entered the ocean in the form of water (HTO). As tritium exists as water itself, it has been regarded as an ideal tool to study the transport of water masses. In April 2001 we collected water samples in the western Japan Basin (WJB) for tritium and helium measurement. The timely sampling provided direct evidence of the bottom water formation, resulting in the drastic increase in tritium concentration from 0.3 TU in 2000 to 0.67 TU in 2001. Considering that the new bottom waters were found mostly in the WJB, it implies that maximum 1% of the whole bottom layer below 2600 m should be replaced with the surface water during the severely cold winter 2000 2001. $^3H-^3He$ age, showing the elapsed time since the water left from the surface, can be used to calculate oxygen utilization rate by dividing AOU by the age. Under the condition of 90% oxygen saturation in the surface water, the integration of OUR in the water column below 200 m yields net oxygen consumption of 12 mol $(O_2)m^{-2}yr^{-1}$, which corresponds to the export production of $99\;g\;C\;m^{-2}yr^{-1}$. This estimate is comparable to a previous estimate based on satellite data and implies that the ratio of export to primary production(f-ratio) is as high as 0.5 in the WJB.

• Ocean and Polar Research
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• 제35권2호
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• pp.107-121
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• 2013

The underwater glider is an autonomous vehicle that can glide through the ocean interior by using a pair of wings attached to its body and can move up and down through the water column by changing its buoyancy. As of now, there are three widely-used gliders, namely, the Spray that was co-developed by Scripps Oceanographic Institution and Woods Hole Oceanographic Institution, the Slocum produced by the Webb Research Cooperation, and the Seaglider that was produced by the University of Washington. In this paper, I will introduce these three gliders and discuss the principles and procedures related to glider operation as well as the application and extendability of modern physical and bio-geochemical sensors to gliders. My experiences in developing a glider for measuring ocean turbulence and testing it 7 times during 12 days are shared in this paper. On the basis of my experiences and knowledge, different kinds of aspects that should be considered for successful glider operation are discussed. In addition, a suggestion is made as to what would be the ideal way to operate underwater gliders in the East/Japan Sea. At the end, the current status of active glider operation teams is presented and the efforts to proceed toward future gliders are briefly introduced.

• 한국항해학회지
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• 제11권2호
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• pp.1-31
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• 1987

Nowadays, the transportation of almost all cargoes depends on sea routes in international trade. In the transaction of trade, cargo transportation must be completed on the base of two contrary objectives, one of which is to protect the vessel, cargoes and crew aborad her safely through every step of the transportation and the other is to pursue profits from the transaction of the trade. In spite of the great development of the modern techniques in shipbuilding today, many sea disaters of big merchant vessels have been occurring successively in winter seasons every year on the sea routes of the North Pacific Ocean. Whenever the accident of losing a vessel in rough sea occurred , many experts of the country to which the vessel belonged had tried to take out the reason of the missing without manifesting the exact cause of the unhappy occurrence. In this paper, we calculated ocean wave status along the route of the North Pacific Ocean theoretically concluded by us as optimum on the basis of weather and sea conditions. In the calculation, we used ITTC wave spectrum formula and meteorological data of "Winds '||'&'||' Waves of the north Pacific Ocean" edited by Ship Research Institute of Japan on the basic data assembled by World Meterological Organization through past 10 years. We selected three sample vessels of most common size in the North Pacific Ocean Routes, a container, a log carrier and a bulk carrier and applied tree sample vessels to the calculated sea conditions for getting the rolling angles of the vessels and stress exerting on the hulls. Examining the calculated results, we concluded as follows; 1. Under the condition of these status7 by beaufort scale, "heave to" maneuvering is the best and safest way to steer every vessel. 2. The most dangerous part of sea area along the west bound optimum route of the North Pacific Ocean in winter season, is the southern sea area of the Kamchatka peninsula.a peninsula.

• 대한지질공학회:학술대회논문집
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• 대한지질공학회 2005년도 정기총회 및 학술발표회
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• pp.107-110
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• 2005

현재 한국의 지진 관측은 1905년도에 시작된 이후로 계속적인 지진 관측망 확충과 새로운 장비의 도입으로 선진국 못지않은 장비를 보유하고 있지만, 지진의 관측과 분석에 있어서는 그 수준이 미흡한 것이 현실이다. 특히, 동해안 지진원 인자 분석에 있어서 시간이 많이 소요되기 때문에 지진 경보나 지진 해일 경보를 발령하는데 어려움이 있다. 이번 연구에서는 일본에서 사용하는 지진 관측망, 한국 지진 관측망(KMA), 그리고 국제 관측망(IRIS) 지진 관측소(4개소)의 파형 포맷을 하나의 공통 파형 포맷으로 변환 ${\cdot}$합성하고 공유 분석 프로그램인 FESNET(극동 지진 관측망 분석 체계)를 구축하여 2004년 5월 29일 울진 지진과 2005년 3월 20일 일본 후쿠오카 지진의 분석을 행하였다.

• 한국양식학회지
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• 제20권2호
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• pp.81-84
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• 2007

We studied two research items that can be undetermined issues in the artificial seed production of the Japanese scallops, Patinopecten yessoensis, batch-specific quality of the reproductive outputs and nursery acclimation, in the embayed waters of Yangyang, Gangwon, Korea. The first batch of the spawner showed better results in terms of survival, growth, and resistance against parasitic ciliate infection over the second batch that was obtained in 5 days after first batch from the same spawner. The early attached spats directly placed in the farming ground (the unacclimated) were resistant against the water current of the open environment, by showing survival of about 80% for a month, a normal survival compared with other results. However, the spat survival during the nursery acclimation was significantly lowered in comparison with that in the unacclimated condition (P<0.01). We discussed the research results of the two items, particularly focusing on their availability for mass seed production for aquaculture in the Korean coastal waters of the East Sea (Sea of Japan).

• 대기
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• 제28권1호
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• pp.15-24
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• 2018

Sea ice plays an important role in modulating surface conditions at high and mid-latitudes. It reacts rapidly to climate change, therefore, it is a good indicator for capturing these changes from the Arctic climate. While many models have been used to study the predictability of climate variables, their performance in predicting sea ice was not well assessed. This study examines the predictability of the Arctic sea ice extent from ensemble prediction systems. The analysis is focused on verification of predictability in each model compared to the observation and prediction in particular, on lead time in Sub-seasonal to Seasonal (S2S) scales. The S2S database now provides quasi-real time ensemble forecasts and hindcasts up to about 60 days from 11 centers: BoM, CMA, ECCC, ECMWF, HMCR, ISAC-CNR, JMA, KMA, Meteo France, NCEP and UKMO. For multi model comparison, only models coupled with sea ice model were selected. Predictability is quantified by the climatology, bias, trends and correlation skill score computed from hindcasts over the period 1999 to 2009. Most of models are able to reproduce characteristics of the sea ice, but they have bias with seasonal dependence and lead time. All models show decreasing sea ice extent trends with a maximum magnitude in warm season. The Arctic sea ice extent can be skillfully predicted up 6 weeks ahead in S2S scales. But trend-independent skill is small and statistically significant for lead time over 6 weeks only in summer.