• 한국항만경제학회지
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• 제31권3호
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• pp.121-140
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• 2015

본 연구는 여수시권의 해양관광교통체계 구축 방향을 강구하였다. 우리나라 남해안의 해양관광을 활성화시키기 위해서는 중심에 위치한 여수시의 효율적인 관광교통체계 구축이 필요하기 때문이다. 연구의 진행은 여수시권의 해양관광교통체계의 문제점을 분석하고, 이를 미국의 베이지역(Bay Area)과 비교하여 개선방안을 도출하였다. 연구 과정에서 여수시권의 해양관광 지원 교통체계는 광역교통과 도시교통 및 교통정보 체계 등에서 베이지역에 비해 미흡하게 평가되었다. 이에 따라 본 연구는 광역교통수단과 도시교통수단을 해양관광교통수단과 연계시키는 지원교통체계의 구축방향을 제시하였고, 추가적으로 여수시 인접지역과의 해양관광 공조 지원교통체계 구축방향도 다루었다. 또한 해양관광 지원 통합교통정보 제공방향도 제안하였다. 이 같은 해양관광교통 통합지원체계 구축을 통해서 교통비용과 통행시간의 절감이 가능하게 된다.

• Ocean Science Journal
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• 제40권3호
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• pp.109-117
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• 2005

Daily changes in phytoplankton abundance and species composition were monitored from July to September 2003 (n=47) to understand which factors control the abundance at a station in Jangmok Bay. During the study, the phytoplankton community was mainly composed of small cell diatoms and dinoflagellates, and the dominant genera were Chaetoceros, Nitzschia, Skeletonema and Thalassionema. Phytoplankton abundance varied significantly from $6.40{\times}10^4$ to $1.22{\times}10^7$ cells/l. The initially high level of phytoplankton abundance was dominated by diatoms, but replacement by dinoflagellates started when the NIP ratio decreased to <5.0. On the basis of the N/P and Si/N ratios, the sampling periofd could be divided into two: an inorganic silicate limitation period (ISLP, $14^{th}$ $July-12^{th}$ of August) and an inorganic nitrogen limitation period (INLP, $13^{th}$ of August - the end of the study). Phosphate might not limit the growth of phytoplankton assemblages in the bay during the study period. This study suggests that phytoplankton abundance and species composition might be affected by the concentrations of inorganic nutrients (N and Si), and provides baseline information for further studies on plankton dynamics in Jangmok Bay.

• 한국수산과학회지
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• 제1권1호
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• pp.1-7
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• 1968

Formerly T. Nishimura, T. Oshima and M. Otsuru studied on Anisakis-like larvae in the various marine fishes from the Japan Sea and the Pacific Ocean. In the present observation, many kinds of marine fishes from the Yellow Sea and the southern coast of Korea were. studied, with the samples from the islands: Eocheng-do, Sohuksan-do, Chuja-do and Keomun-do. The authors examined 313 samples from the adjacent waters of Korea and the distribution of the Anisakis-like larvae in the fish body was found to be 9,219 larvae of Anisakis-like larvae found in the mesentery and coelomic cavity of all samples. Of them, 8,112 Anisakis-like larvae were found from 187 samples from the southern coast of Korea, 1,107 Anisakis-like larvae were found in 126 samples from the Yellow sea (Tables 1 & 2). The fish from the southern coast of Korea are much more infected than the fish from. the Yellow Sea. The larger the fish length, the heavier infection of Anisakis-like larvae were observed.

• 한국수산과학회지
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• 제43권3호
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• pp.254-261
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• 2010

The feeding habits of six shark species, Scyliorhinus torazame, Mustelus manazo, Squalus megalops, Isurus oxyrinchus, Alopias pelagicus, and Carcharhinus plumbeus were studied using the stomach contents of 463 specimens collected between January and February 2007 in the southern sea of Korea. They consumed different prey items. S. torazame preyed mainly crustaceans, and M. manazo on crustaceans and fishes. S. megalops, I. oxyrinchus, A. pelagicus, and C. plumbeus consumed predominately fishes. Non-metric multi-dimensional scaling (NMDS) ordination plots emphasized that dietary similarities separated thesix shark species into three trophic groups based on similarities in percentage Index of Relative Importance (%IRI): Group I (crustacean feeders), Group II (fish and crustacean feeders), and Group III (fish feeders).

• 한국수산과학회지
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• 제39권1호
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• pp.35-41
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• 2006

The feeding habits of Spanish mackerel (Scomberomorus niphonius) were studied based on the examination of stomach contents of 445 specimens collected from January to December 2004, in the Southern Sea of Korea. The size of Spanish mackerel ranged from 26.1 to 105.4 cm in fork length (FL). Spanish mackerel was a piscivorous fish which mainly consumed teleost fishes such as chub mackerel (Scomber japonicus) and anchovy (Engraulis japonicus). Its diet also included small quantities of shrimps, stomatopods, cephalopods, crabs, polychaetes, amphipods, cumaceans and copepods. Smaller individuals (<60 cm FL) consumed small fishes such as Engraulis japonicus and crustaceans. The portion of these prey items decreased with increasing fish size, and this decrease was paralleled with increased consumption of lager fishes such as Scomber japonicus and Cololabis saira. The prey size increased with the increase of fish size.

• Ocean Systems Engineering
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• 제12권3호
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• pp.335-358
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• 2022

Hydrodynamic field alteration around a cylindrical pier using a curved vane is numerically investigated. The curved vane with various angles ranged from 10 to 220 degree is placed at the upstream of the cylindrical pier. Laminar flow is adopted in order to perform the steady-state analysis. It is found that the flow separation leads to the formation of four bubbles depending on the value of the curved vane angle. Two bubbles are located in the region between the rear of the curved vane and the leading surface of the cylindrical pier, while the remaining two bubbles are located at the wake zone behind the cylindrical pier. Numerical analysis is performed to reveal the hydrodynamic field and influence of curved vane on the formation and evolution of the bubbles. It is found that the center and size of the bubble depend mainly on the value of the curved vane angle. It is observed that the flow velocity vector shows clearly the alteration in the flow velocity direction especially at the leading surface and rear surface of the curved vane owing to the occurrence of flow separation and flow dissipation along the circumference of the vane.

• 한국해양학회지:바다
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• 제21권2호
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• pp.49-57
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• 2016

기후변화를 일으키는 외부강제력이 전지구적으로 동일하게 주어지더라도 그에 따른 기후변화와 되먹임 효과는 지역마다 다르게 나타난다. 따라서 기후변화에 나타난 내부변동성 및 다른 잡음 효과로부터 지구온난화 신호를 구별하기 위한 기후변화 탐지는 전구평균뿐만 아니라 지역규모에서도 이뤄져 왔다. 본 논문은 지구온난화로 인해 미래에 전례 없는 기후가 나타나는 시기를 추정하고 그 지역적 차이를 분석함이 목적이며 이를 위해, 기후모형 자료를 이용한 기존 연구와는 달리, 관측 자료를 이용하여 내부변동성을 추정하고 미래 온도변화를 전망하였다. 전례 없는 기후 시기는 미래에 예측된 지표 온도가 과거 관측 기록에 나타난 온도 범위를 벗어나 전례 없이 따뜻한 기후가 이후로도 지속되는 시점으로 정의하였다. 1880년부터 2014년까지 관측된 지표온도 아노말리의 연평균 시계열을 이용하여 온난화 선형추세를 계산하였고, 이 추세로부터 벗어난 최대 변이 값을 내부변동성의 크기로 간주하였다. 관측 자료로 구한 온난화 선형추세와 내부변동성의 크기가 미래에도 유지된다고 전제하고 계산한 결과에 따르면, 육지에서 전례없는 기후는, 아프리카는 서쪽에서, 유라시아는 인도와 아라비아 반도 남부 등 저위도에서, 북아메리카는 캐나다 중서부와 그린란드 등 고위도에서, 남아메리카는 아마존을 포함하는 저위도에서, 남극대륙은 로스해 주변지역에서 향후 200년 이내에 비교적 빨리 나타나며, 우리나라를 포함한 동아시아 일부 지역에서도 200년 이내로 빨리 나타난다. 반면에 북유럽을 포함하는 고위도 유라시아 지역과 미국과 멕시코를 포함하는 북아메리카 중남부에서는 400년 이후에 나타난다. 해양에서는 전례 없는 기후가 인도양, 중위도 북대서양과 남대서양, 남극해 일부 해역과 남극 로스해, 북극해 일부 해역에서 200년 이내로 비교적 빨리 나타나는 반면, 내부변동성이 큰 동적도태평양, 중위도 북태평양 등의 일부 해역에서는 수천 년이 지나야 오는 곳도 있다. 즉, 전례 없는 기후시기는 육지에서는 대륙마다 서로 다른 양상을 보이고 해양에서는 온난화 추세가 큰 고위도 해역을 제외하면 내부변동성의 영향을 많이 받는다. 결론적으로 지구온난화로 인한 전례 없는 기후는 특정 시기에 공통적으로 나타나는 것이 아니라 지역에 따라 시기적으로 상당한 차이가 있다. 따라서 기후변화 대응책을 마련할 때 온난화 추세뿐만 아니라 내부변동성의 크기도 함께 고려할 필요가 있다.

• 한국해양공학회지
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• 제31권4호
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• pp.315-323
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• 2017

This paper presents an integrated navigation system that combines ultra-short baseline (USBL), Doppler velocity log (DVL), and heading measurements for a deep-sea remotely operated vehicle, Hemire. A navigation model is introduced based on the kinematic relation of the position and velocity. The system states are predicted using the navigation model and corrected with the USBL, DVL, and heading measurements using the Kalman filter. The performance of the navigation system was confirmed through re-navigation simulations with the measured data at the Southern Mariana Arc submarine volcanoes. Based on the characteristics of the measurements, the design process for the parameters of the system modeling error covariance, measurement error covariance, and initial error covariance are presented. This paper reviews the influence of the outliers and blackout of the USBL and DVL measurements, and proposes an outlier rejection algorithm that is robust to USBL blackout. The effectiveness of the method is demonstrated with re-navigation for the data that includes USBL blackouts.

• Ocean and Polar Research
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• 제43권4호
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• pp.307-320
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• 2021

Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

• Ocean and Polar Research
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• 제43권3호
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• pp.127-140
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• 2021

At the estuaries of Bonggang and Miryong streams in the Korean southern coast, the spatiotemporal distribution and habitat environment of a nerite snail, Clithon retropictum (Gastropoda: Neritidae), which has been assigned as a legally protected species of Korea, were explored. Physicochemical environmental factors such as water temperature, salinity, tidal level distribution as well as biotic environments (chlorophyll-a concentration and epilithic microalgae composition) were monitored every month. The relationships between the environmental factors and spatiotemporal distribution of the nerite snail population were analyzed. Water temperature, salinity, and water level varied by season and lunar tidal rhythm. The spatiotemporal distribution of the nerite snail was mostly related to water salinity. Among epilithic algae which were the priority prey of snails, blue-green algae and green algae dominated in summer and autumn, while diatoms predominated during winter and spring. Chlorophyll-a concentration was highly and positively correlated with the population density of the nerite snail. The correlation coefficients were different depending on the taxon (Family) of epilithic algae. The mean population density was 302.2 inds m^-2 and 271.8 inds m^-2 in Bonggang Stream and Miryong Stream, respectively. The egg capsules of the nerite snail in the two habitats were observed from March (in Bonggang Stream) or April (in Miryong Stream) to August, and newly hatched juveniles recruited in the habitats from August were assessed with regard to frequency distributions of shell width. The occurrence of large-sized snails in upper stream reaches of both Bonggang and Miryong indicated the movement of spats from the mouth to the upper reaches during the whole life cycle.