• 한국해양학회지
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• v.26 no.3
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• pp.278-290
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• 1991

A synoptic survey of chemical properties was carried out at 21 stations in the Ulleung Basin in May 1988 on board T/V HANBADA. Vertical structures of typical profiles are: surface mixedlayer waters in the upper 30∼40 m with depleted nutrients concentrations, thermocline waters with rapid variations in all physical and chemical properties. and deep Waters below 200 m which are nearly homogeneous. Along the northern section at 37$^{\circ}$12'N. The salinity minimum layer was observed at about 190m. which characterize the East Sea Intermediate Water (ESIW). The dissolved oxygen concentration in this layer was about 230∼ 275uM, lower than 290uM (6.5ml/l) which is the previously known characteristics of the ESIW. However, apparent oxygen utilization (AOU), nitrate, phosphate and silicate show systematically low concentration in the salinity-minimum layer. The low values of AOU and all the nutrients associated with the salinity-minimum, may be useful to identify the ESIW and serve as a new tracer in the East Sea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.289-296
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• 2009

The appearance and variation of cold water area and its expansion mechanism of tidal front in the south western coast of Korea in summer were studied on the basis of oceanographic data(1966-1995), satellite images from NOAA and SeaWiFs and numerical model. Cold water appearance in southwestern field of Jindo was due to the vertical mixing by strong tidal current. Tidal front where horizontal gradient of water temperature was more than $0.3^{\circ}C$/km parallels to contours of H/$U^3$ parameter 2.0~2.5 and the outer boundary of cold water region corresponds with contours of the parameter 2.5~3.0 in the southwestern sea of Korea during the period between neap and spring tides. The position replacement of tidal front formed in the study ares varies in a range of 25~75km and cold water region extends about 90km. These suggest that the magnitude of variation of frontal position and cold water area was proportionate to the tidal current during lunar tidal cycle. Moreover, it was estimated that the southwestward expansion of cold water region was derived from the southwestward tide-induced residual currents with speed more than 10cm/s.

• Proceedings of the Korea Water Resources Association Conference
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• 1989.07a
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• pp.113-114
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• 1989

원자력, 화력발전소, 제철소 등의 다양한 임해 공업시설로부터 방출되는 냉각용 온배수는 연안일대 해수의 열균형을 파괴시켜 생태계의 보존 및 환경관리에 좋지 못한 영향을 야기케 된다. 이러한 영향은 해안 또는 만내의 수중온도를 전반적으로 높일뿐 아니라 가동중단시 갑자기 수온을 떨어뜨려 해양생물상에 피해를 줄수도 있다. 또한 온배수에 의하여 온도가 상승된 해수가 취수구를 통하여 재순환되어 냉각기능의 부진을 초래하게되면 발전효율 또는 기계가동율을 저하시키게 된다. 이러한 측면에서 온배수의 확산에 대한 정성, 정량적인 예측은 환경영향평가, 취.배수구 설계조건의 산정 등에 매우 중요한 문제라 하겠다. 본 연구는 정지수역으로 유입하는 3차원 정상류 표면온배수 해석모형의 개발로서 개발된 모형의 수치실험을 통하여 온배수 확산의 물리적 특성을 규명한다. 지배방정식에 나타나는 Reynolds 응력항($)과 온도유동 프럭스항($)의 해석에서 필요한 난류모델은 k-$\varepsilon$ 모형에 난류 평균자승 온도유동($) 및 그 감쇄방정식을 추가한 4-방정식 모델로서 구성하였다. 아울러 3차원 정상류 모형에서 야기되는 타원형 방정식을 포물형 방정식의 형태로 전환하여 효과적으로 해석할 수 있도록 모델의 특성을 정리하였다. 본 모델의 검증을 위하여 Lal 및 Rajaratnam(1977)의 물리적 실험값과 비교해본 결과 온배수 거동의 물리적현상이 잘 일치하였다. 또한 McGuirk 및 Rodi(1979)에 의해 개발된 2-방정식 k-$\varepsilon$ 난류모형의 해석결과에 대하여 비교분석을 실시하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.219-229
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• 1984

Physical and chemical survey on western channel of the Korea Strait was made using oceanographic data from July 25 to July 31, 1983. Four water types were distinguished at western channel: runoff of the Nakdong River, Tsushima Current Waters, Keoje Coastal Waters, and Ulsan Coastal Waters. Influence of the Nakdong River was greater at Southern East Coast near Yeong-Do Island in Pusan than at Keoje Coast. General characteristics of these four water types were as follows : For runoff of the Nakdong River, transparency was within 3 m, water colour chinese yellow (number 11), surface temperature $18{\sim}19^{\circ}C$, salinity less than $31\%0$, surface dissolved oxygen (D.O.) $4.5{\sim}5.0ml/l$, contents of phosphate $0.25{\sim}0.5{\mu}g-at./l$ ; these values were the highest among these four water types. For Tsushima Current waters, transparency was greater than 15 m, waters color blue (number $2{\sim}4$), surface temperature about $23^{\circ}C$, salinity $32{\sim}33\%0$, and surface D.O. greater than 5,0 ml/l. Phosphate, nitrate and silicate were less than 0.25, 2.0, and $2.5{\mu}g-at./l$, respectively; these values were the lowest among these four water types. Keoje Coastal Waters had low temperature ranging $20{\sim}21^{\circ}C$ at surface, and high salinity greater than $33\%0$. D.O. was less than 5.0 ml/l, phoshpate, $0.5{\mu}g-at./l$ nitrate and silicate were less than $3.5{\mu}g-at./l$. Ulsan Coastal Waters had the lowest surface temperature among these four types; surface temperature was less than $16^{\circ}C$, salinity greater than $33.5\%0$, and D.O., phosphate and nitrate had very high values. It seems that these high values resulted from upwelling phenomena.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.553-568
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• 2018

Chromophoric Dissolved Organic Matter (CDOM) plays a dominant role in absorbing UV-VIS light and is also important in the biogeochemical carbon cycle due to the production of carbon dioxide from photo-oxidation at the sea surface in marine environments. Since absorption by CDOM was recently found to be responsible for increasing the energy absorbed in the mixed layer by 40 % over pure seawater, the importance of CDOM absorption in seawater for increasing sea surface temperature has come to be well recognized. We measured aCDOM and the absorption characteristics of CDOM during spring 2012 and 2014 in the southwestern East Sea. Distribution of CDOM in spring 2012 and 2014 was compared and S value was used to find the source of CDOM in the study area. As a result, the average $a_{CDOM}$ was $0.237m^{-1}$ ($0.009{\sim}0.988m^{-1}$) and the average S value was $16{\mu}m^{-1}$,which shows coastal properties. Also a positive correlation between Chl a and CDOM was observed ($r^2=0.34$), with an especially strong correlation near coastal stations. aCDOM in 2014 was about 40 % higher than aCDOM in 2012 during spring in the study area. This difference in aCDOM concentration resulted not only from annual variation but also from stratification and photobleaching in late spring 2012. This observation implies the possibility of flux of carbon dioxide into the atmosphere as a result of photo-oxidation in the East Sea.

• 한국해양학회지
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• v.27 no.4
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• pp.332-341
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• 1992

한반도 주변의 정규적인 해양관측 효시는 1910년대로부터 시작된다. 1915년 6월부 터 원산, 부산 등 12개 항구의 중앙부에서 10일 간격으로 해양관측이 시작되었으며, 1916년 7월부터는 거문도 해야 어청도 등 10개 등대관측소에서 연안정지관측을 역일로 시작했고, 1917년 5월부터 정선해양관측이 이루어 졌는데 이들은 총독부 수산과에서 수산시험조사사업의 일환으로 수행되었고 1921년부터 총독부수산 시험장에서 이들을 더욱 발전다. 1930년대에는 정선해양관측이 매월 초순 각 도별로 수항되어 가장 훌륭 한 관측결과가 생산되었다. 1961년부터는 항구관측을 폐지하고 연안정지관측과 정선해 양관측만 이루어 지고 있으며 해양조사선을 20여개로 수정하여 2개월마다 조사에 임하 고 있다. 이들은 기본적으로 해양생물자원의 경제적 획득에 목적을 두고 있으나 자료 를 널리 공개하여 전세계의 어느 해양연구자들도 이용할 수 있도록 하고 있다. 1960년 부터는 우리 나라 연안의 조석관측도 연속적으로 수행되고 있다. 1990년 현재 21개 정 선해양관측자료와 42개의 연안정지관측자료, 매일의 표면수온분포도 21개의 평균해면 자료가 공개적으로 이용가능하다. 앞으로 유명한 연구소일수록 해양관측자료를 공개하 여 공동이용할 수 있어야 하며 해양관측의 활성화를 위해 첫째 해양관측기구를 소모품 으로 취급할 것이 요구되고, 둘째 관측선 요원의 정당한 처우가 이루어져야 하며, 셋 째 세계적인 해양조사 사업은 국가기관에서 더욱 성실히 수행될 수 있도록 여건을 조 성할 필요가 있다. 과거에는 어업활동을 위해 해양조사가 현재에는 기후변동연구에 중 요한 자료로도 이용되고 있으므로 우리는 우리주변의 해양관측을 미래학문의 기초자료 로 끊임없이 수행해야 할 중차대한 임무를 지니고 있다.는 대체로 Weddell Sea쪽에서 남동쪽으로 가면서 증가하며, 영 양염 농도가 낮은 얼음 녹은 물의 유입이 얼룩소 a의 농도를 감소시키는 것으로 사료 된다.되어, 경기만에서 출현하는 식물플랑크톤이 서해 중동부 연안수역에서 출현하는 식물 플랑크톤보다 상대적으로 낮은 광에 적응되어 있었다. the most important in the global optimum analysis because small variation of it results in the large change of the objective function, the sum of squares of deviations of the observed and computed groundwater levels. 본 논문에서는 가파른 산사면에서 산사태의 발생을 예측하기 위한 수문학적 인 지하수 흐름 모델을 개발하였다. 이 모델은 물리적인 개념에 기본하였으며, Lumped-parameter를 이용하였다. 개발된 지하수 흐름 모델은 두 모델을 조합하여 구성되어 있으며, 비포화대 흐름을 위해서는 수정된 abcd 모델을, 포화대 흐름에 대해서는 시간 지체 효과를 고려할 수 있는 선형 저수지 모델을 이용하였다. 지하수 흐름 모델은 토층의 두께, 산사면의 경사각, 포화투수계수, 잠재 증발산 량과 같은 불확실한 상수들과 a, b, c, 그리고 K와 같은 자유모델변수들을 가진다. 자유모델변수들은 유입-유출 자료들로부터 평가할 수 있으며, 이를 위해서 본 논문에서는 Gauss-Newton 방법을 이용한 Bard 알고리즘을 사용하였다. 서울 구로구 시흥동 산사태 발생 지역의 산사면에 대하여 개발된 모델을 적용하여 예제 해석을 수행함으로써, 지하수 흐름 모델이 산사태 발생 예측을 위하여 이용할 수 있음을 입증하였다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.24-37
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• 2001

Physical and chemical properties of the northest Equatorial Pacific between 5° and 12° N along 131.5 °W wore investigated in association with changes in water column structures during the summer seasons of 1998 and 1999. Climatic disturbances such as El Nino and La Nina, should have affected this area during the study Period. In 1998, a thermocline where temperature rapidly decrease with depth, was formed at 90～110 m water depth. Nutrient depicting areas, specially for nitrate+nitrite and phosphate, or oligotrophic regions were extended down to approximately 100 m depth, which coincided with the surface mixed layer depth. However, in 1999, a very fluctuating thermocline was observed with latitudes. As a result of changes in the water column structures, nutrient concentrations also showed fluctuation parallel to the changes in other physical parameters. In the photic zone, depth integrated nitrogen and phosphorus values were 34 gN/m², 7 gP/m² in 1998 and 130 gN/m², 18 gP/m² in 1999, respectively. The results indicated that nitrogen (96 gN/m²) and phosphorus (11 gP/m²) are supported by up-welling and down-welling phenomena with convergence and divergence in the study area.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.83-94
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• 1999

A Study on the choice of proper region for moving cage culture facilities were carried out in the South Sea of Korea. Optimum temperatures of habitats for cage culture fishes, Sebastes schlegeli, Paralichthys olivaceus, Seriola quinqueradiata, Lateolabrax japonicus, Pagrus major, Takifugu vermicularis, and Mugil cephalus were 18~26$^{\circ}C$, 10~$25^{\circ}C$, 15~29$^{\circ}C$, 15~29$^{\circ}C$, 15~3$0^{\circ}C$, 15~$25^{\circ}C$, and 19~27$^{\circ}C$, respectively. In winter, wintering regions for continuous growth of fishes were proper around Komundo, Sorido, Soimal, Gadukdo and Chejudo for Paralichthys olivaceus and Lateolabrax japonicus, while Seoguipo and Udo for Seriola quinqueradiata, Pagrus major and Takifugu vermicularis. Sanji was not proper for wintering region because variation of water temperature is large by effect of strong northwestern wind. Wintering regions of Sebastes schlegeli and Mugil cephalus were not in the south of Korea. In summer, proper regions for fishes to avoid from damage by red tide were Komundo and around Chejudo. No red tide has occurred in these regions for 6 years. Mokpo and Yoja Bay were not proper for moving region because the former had strong tides and the latter had only one exit out of the bay which made it impossible to move cages in other route when dangerous red tides burst into.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.221-229
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• 1990

The horizontal distribution of squid gill-net fishing ground in the North Pacific Ocean was examined within the main fishing season, May to October, during 1986~1989. Data of sea surface temperature were selected from Technical Reports of National Fisheries Research Development Agency of Korea, Data Records of Hokkaido University, Deep-sea Training Reports of Korea Fishing Training centre, Fishing Operation Reports of Daelim Fisheries Co., Ltd., Oyang Fisheries Co., Ltd. and Dong-won Industrial Co., Ltd.. Data of catch were also collected from Deep-sea Training Reports of Korea Fishing Training Centre and Fishing Operation Report of three fisheries companies in Korea. The fishing ground was segmented in every 1 degree of latitude from $34^{\circ}N$ to $46^{\circ}N$ and 2 degree of longitude from $144^{\circ}E$ to $162^{\circ}W.$ The distribution and centeroid of fishing ground, fished and optimum surface temperature, catch per unit effort (CPUE) in the fishing ground were computed, based on the above data. The resulted obtained can be summarized as follows: 1. Range of fishing ground can be estimated as $35^{\circ}~40^{\circ}N,$ $178^{\circ}~166^{\circ}W$ in May, $36^{\circ}~41^{\circ}N,$ $178^{\circ}E~166^{\circ}W$ in June, $38^{\circ}~44^{\circ}N,$ $170^{\circ}E~170^{\circ}W$ in July, $39^{\circ}~44^{\circ}N,$ $144^{\circ}~180^{\circ}E$ in August, $39^{\circ}~44^{\circ}N,$ $144^{\circ}~170^{\circ}E$ in September and $40^{\circ}~44^{\circ}N,$ $144^{\circ}~154^{\circ}E$ in October. 2. Fishing ground in May, June and October is similarly distributed along longitude and latitude, but the range of the former is larger than that of the latter in July, August and September. Monthly centeroids of fishing sectors is estimated as #3888 in May, #3884 in June, #4078 in July, #4154 in August, #4146 in September and #4044 in October respectively. 3. Fished temperature and optimum and temperature are estimated as $14.0~18.5^{\circ}C$ and $15.0~16.0^{\circ}C$ in May, $13.5~18.5^{\circ}C$ and $14.5~16.0^{\circ}C$ in June, $14.0~20.0^{\circ}C$ and $14.5^{\circ}C,$ $19.0^{\circ}C$ in July, $16.0~21.5^{\circ}C$ and $18.0~20.0^{\circ}C$ in August, $14.5~22.0^{\circ}C$ and $17.0~18.5^{\circ}C$ in September, $14.0~18.0^{\circ}C$ and $16.0~17.0^{\circ}C$ in October. 4. Monthly mean CPUE which corresponds to the net weight of catch(kg) divided by the sheet number of operated gillnets is calcuted as 3.2, 4.5, 4.3, 5.1, 6.4 and 5.8 kg/sheet respectively. 5. Considering the monitoring program of the squid gill-net fishery in the North Pacific Ocean during 1989~1990, set by the Korean Government, 12 sectors may be restricted out of 21 fishing sectors in May, 7 out of 24 in June, 4 out of 25 in July. They are free from restriction hereafter August.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.297-302
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• 2022

An exothermic oil absorbent sheet with calcium chloride crystals can be fabricated, by dipping a clean polypropylene fabric in calcium carbonate and hydrochloric acid solution and drying it. The exothermic oil absorbent sheet applied to the seawater surface, releases heat by the dissociation of calcium chloride. The dissociation heat liquefies the solidified low-sulfur fuel oil at a low temperature, and converts it to a state at which it can be absorbed. The optimum mole concentrations of calcium carbonate and hydrochloric acid required for the exothermic oil absorbent sheet, are 0.25 M and 0.5 M, respectively. The oil absorption capacity of the exothermic oil absorbent sheet for low sulfur fuel oil depends on the seawater temperature. But, it is highly excellent at 4.5-7.08 g/g at 10℃, the average seawater temperature during the winter in Korea. The exothermic oil absorbent sheet is an excellent alternative in absorbing low-sulfur fuel oil in winter and removing it from seawater.