• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.156-158
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• 2007

The radiance observed from the ocean depends on the illumination and viewing geometry along with the water properties, and this variation is called the bidirectional effect which is important to be considered in ocean color remote sensing. In the present study, as a preliminary step, the spectral-angular radiances in coastal water were investigated with experiments for a range of viewing geometric conditions $(0-70^{\circ})$. Over a phytoplankton-dominated water surface the upward radiance for visible and near-infrared wavelengths (example, SeaWiFS and GOCI) increased at nadir and decreased toward the near-horizon, becoming dependent of viewing angles (with higher radiance at nadir view angle and lower radiance at near-horizon viewing angle). This variations were better expressed by the Q-factor, which relates upwelling radiance to the upwelling irradiance (i.e., $Q=E_u/L_u$, also dependent on Sun's position). The Q-factor for this case was more non-uniform with the considered wavelengths and was dependent on viewing geometric conditions. These experimental results confirm the previous similar findings in other coastal waters.

• 상하수도학회지
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• 제18권6호
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• pp.785-793
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• 2004

Coagulation has been investigated for pretreatment of low-pressure membrane systems such as microfiltration and ultrafiltration. Coagulation pretreatment can reduce foulants (particles and organic matter) prior to membrane filtration. However, when in-line coagulation or submerged type of filtration is used, flocculent aggregates could act as a foulant depending on concentrations and specific properties of floc. A natural water and three synthetic waters were used to investigate effects of coagulation pretreatment and presence of flocculent aggregates on membrane fouling. Coagulation pretreatment shows that foul ants were effectively removed during coagulation and the formed cake layer on the membrane surface had less resistances compared to raw natural water. In addition, little difference in membrane fouling was found by flocculent aggregates from the natural water. Interestingly, however, the results by three synthetic waters indicated that flocculent aggregates could have adverse effects on membrane fouling in a specific condition.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.115-119
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• 1999

During mechanical pulp production and blcaching wood components, such as extractives, carbohydrates and lignin are dissolved and dispersed into the process waters. These components are called dissolved and colloidal substances(DCS). DCS can accumulate during water circulation and can in turn affect paper machine runnability and also the strength and optical properties of the paper. In this work DCS fraction origination from TMP process were treated with enzymes acting on triglycerides. glucomannans, and lignin and the effect of enzymatic treatments on the water composition as well as sheet properies were evaluated. Lipases were found to modify the chemical structure of the extractives resulting in more hydrophilic fibre surface and subsequent improvement in the sheet strength properties. Mannanase treatment, on the other hand, destabilized pitch. As a result, aggregation of pitch to the fibres was observed which in turn resulted in impaired strength properties. Laccase could effectively polymerize lignans and the reaction products seemed to be sorbed onto the fibres.

• Journal of Species Research
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• 제1권2호
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• pp.156-174
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• 2012

Monchenkocyclops gen. nov. was erected to accommodate M. changi sp. nov. from South Korea (type species), M. mirabdullayevi sp. nov. from Kazakhstan, M. biarticulatus (Monchenko, 1972) comb. nov. from Uzbekistan, and M. biwensis (Ishida, 2005) comb. nov. from Japan. The latter species was originally described from surface-water habitats of the ancient Lake Biwa in the genus Diacyclops Kiefer, 1927, while two Central Asian species were previously collected from groundwater habitats and assigned to the genus Acanthocyclops Kiefer, 1927. Monchenkocyclops changi is also found in subterranean waters, and described here in detail. It is morphologically most similar to its Uzbek congener (not to the Japanese one), which rises some interesting zoogeographical questions about the disjunct distribution of this genus. Range fragmentation is a more plausible explanation for this distribution pattern than range expansion, and we emphasize four lines of evidence that support this hypothesis. Four species of Monchenkocyclops share not only the same segmentation of the swimming legs, but also the exact same armature formula of all swimming legs, in addition to many other morphological characters, such as the caudal rami shape and armature, absence of exopod on the antenna, similar shape of the seminal receptacle, fifth leg, etc. They can be distinguished mostly by the relative length of different armature elements, such as the innermost terminal caudal setae, and inner setae and apical spines on the third endopodal segment of the fourth leg. A dichotomous key to species is provided.

• 한국정보통신학회논문지
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• 제12권12호
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• pp.2265-2270
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• 2008

최근 대두 되고 있는 지구 온난화 및 기후 변화와 관련해서 수온이 해양 생태계에 미치는 영향을 알기 위하여 한반도 주변 해역을 중심으로 $1988{\sim}2000$년까지 NOAA SST자료를 활용하여 어류 회류의 변동성에 대하여 조사하였다. 위성자료를 분석해 본 결과 우리나라는 전반적으로 온난화 경향이 나타나고 있다. 연근해의 수온상승과 비교해 볼 때, 오징어, 멸치, 정어리, 꽁치 등 회유성 어종의 분포해역이 점차 북상하고 있는 것으로 나타났다. 또한 난류성 어종인 오징어와 멸치의 어획량은 증가한 반면, 한류성 어종인 꽁치와 정어리는 감소하는 경향을 보였다. 그러나 어황에 영향을 미치는 요인에는 수온뿐만 아니라 염분 및 오염도 등 여러 가지 요소가 존재하기 때문에 수온상승으로 인해 생기는 어황의 변화라고 단정 짓기는 어렵다. 따라서 금후 기후 변동과 연근해 어황 변화에 대해서도 계속적인 연구가 필요하다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.667-679
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• 2020

As the LNG carrier operates in ice covered waters, it is key to ensure the overall safety, which is related to the coupling effect of ice-breaking process and internal liquid sloshing. This paper focuses on the sloshing simulation of the ice-breaking LNG carrier, and the numerical method is proposed using Circumferential Crack Method (CCM) and Volume of Vluid (VOF) with two main key factors (velocity νx and force Fx). The ship motion analysis is carried out by CCM when the ship navigates in the ice-covered waters with a constant propulsion power. The velocity νx is gained, which is the initial excitation condition for the calculation of internal sloshing force Fx. Then, the ship motion is modified based on iterative computations under the union action of ice-breaking force and liquid sloshing load. The sloshing simulation under the LNG tank is studied with the modified ship motion. Moreover, an ice-breaking LNG ship with three-leaf type tank is used for case study. The internal LNG sloshing is simulated with three different liquid heights, including free surface shape and sloshing pressure distribution at a given moment, pressure curves at monitoring points on the bulkhead. This present method is effective to solve the sloshing simulation during ice-breaking process, which could be a good reference for the design of the polar ice-breaking LNG carrier.

• ALGAE
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• 제37권4호
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• pp.265-279
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• 2022

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km²) was estimated at 11,227 Gg C y^-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

• 해양환경안전학회지
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• 제15권3호
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• pp.165-171
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• 2009

1999년 10월, 12월의 국립수산과학원 정선관측 자료를 이용하여 수온역전 현상이 성층변동에 미치는 영향을 분석하였다. 10월, 12월 모두 수심 25-75m 사이에서 수온역전현상이 빈번하게 발생하며, 12월에는 표층 부근에도 수온역전현상이 나타났다. 고온, 고염분수인 쓰시마난류의 수평 이류가 10월, 12월에 나타나는 수온역전현상의 주원인으로 작용하며, 12월에는 연안역에서 외양역으로 수송되는 차가운 표층수의 영향이 함께 작용한다. 10월에는 북풍이 지속적으로 불지만 남해연안수가 외해역으로 확장하는 현상이 뚜렷하지 않는 반면, 북서풍계열의 풍속이 강해지고 쓰시마난류의 세력이 약해지는 12월에는 남해연안수가 상층부를 통해 외해역으로 확장하면서 수온역전현상을 나타나게 한다. 10월과 12월 모두 수온역전현상이 발생하는 해역을 따라 성층의 변동폭이 크게 나타난다.

• Ocean and Polar Research
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• 제30권3호
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• pp.351-359
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• 2008

In an effort to develop high-resolution sea surface temperature (SST) proxies for mid-latitude regions, two massive reef-building coral species, Alveopora and Favia, were collected from Jeju and Tsushima Islands, respectively. Their skeletons were subsequently analyzed for annual growth banding, Sr/Ca and Mg/Ca ratios. Hermatypic corals are thinly distributed in the waters of Jeju Island, where Alveopora japonica was the only dominant coral species. A higher diversity of hermatypic corals were observed in the waters of Tsushima Island, where Favia sp. was the most common coral species and even forming an about 6-m-high reef structure. Both Alveopora and Favia showed annual growth layers consisting of couplets of high- and low-density bands. Sr/Ca ratio of both species and Mg/Ca ratio of Alveopora also showed seasonal variation, likely reflecting SST variation. These results suggest the possibility that Alveopora and Favia species can be used as potential SST proxies. However, this study also highlights the potential growth disturbance of middle latitude corals due to high rainfall during monsoon and low SST during winter. This possibility should be taken into account in the investigation of Sr/Ca(Mg/Ca)-SST relationships.

• 한국항해항만학회지
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• 제29권6호
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• pp.583-588
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• 2005

하계 한국 남서연안 해역에는 저온수가 나타나고 안개가 자주 형성되는 것으로 알려져 있다. 본 연구에서는 저온수의 출현시기 및 장소와 이 해역에서 형성되는 안개에 미치는 저온수의 영향에 대해 조사${\cdot}$분석하였다. 그 결과, 저수온역은 초여름 대흑산도 부근해역에서 나타나기 시작하여, 이것은 점차 이동하여 7월 말${\~}$8월 초 진도 남서쪽 해역에 위치하고, 그 후 10월 중순경 이 해역에서 소멸된다. 그리고 이 해역에서는 주로 4${\~}$8월에 안개가 발생하는데, 특히 인근해역에 비해 해면온도가 현저하게 낮은 진도해역에서 안개 발생빈도가 높은 것으로 보아, 이 해역에 나타나는 저온수가 안개의 형성에 상당한 영향을 끼치는 것으로 사료된다.