• Title/Summary/Keyword: North Sea

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Investigation of Passing Ships in Inaccessible Areas Using Satellite-based Automatic Identification System (S-AIS) Data

  • Hong, Dan-Bee;Yang, Chan-Su;Kim, Tae-Ho
    • Korean Journal of Remote Sensing
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    • v.34 no.4
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    • pp.579-590
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    • 2018
  • Shipping of North Korea is not yet publicly well documented. Taedong River, the most important sea route of North Korea, is selected as a model study area to show how effectively a remote place can be investigated through the application of satellite-based Automatic Identification System (S-AIS) for understanding shipping and tracks of vessels which passed the lock gate in the Taedong River and visited the nearby ports on its track. S-AIS data of the year 2014 were analyzed on the basis of various time periods, country of registry and category of ships. A total of 325 vessels were observed. The ships under the flags of North Korea, Cambodia and Sierra Leone were found to be dominant in frequencies which accounted for 43.08%, 16.00%, and 8.92%, respectively. Trajectories of the 325 ships in the Yellow Sea were also checked according to the flags. It is concluded that some ships under the flags of Cambodia, Sierra Leone, Mongolia, Panama and Kiribati are regarded as flags of convenience, and ships without flag and ship type codes also comprised a remarkable portion out of the total ships.

Spatiotemporal Fluctuation of Water Temperature in Cheonsu Bay, Yellow Sea (천수만 수온의 시공간적 변동)

  • Choo, Hyo-Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.1
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    • pp.90-100
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    • 2021
  • In the north and northeast of Cheonsu Bay, short-term fluctuations of surface water temperature are large owing to shallow water depth, weak current, and freshwater runoff. However, in the south of the bay, water temperature fluctuations are small owing to the inflow of offshore water by tidal currents. The water temperature in the north of the bay is higher in spring and summer than in the south of the bay, but lower in autumn and winter. During spring season, the fluctuation in the northern surface water temperature is the highest. The temperature fluctuations owing to tides are in phase with the tide in autumn and winter, and in the reverse phase with the tide in spring and summer. The dominant periods of water temperature fluctuations are half a day, daily, 15 days, and 1 month owing to the tide and 7 to 10 days, which are estimated based on atmospheric factors. Half a day and daily water temperature fluctuations are also highly correlated with air temperature and wind fluctuations. The sea area where water temperature fluctuations are highly correlated is divided into the north and south of the bay. The fluctuation phase is faster in the north of the bay than in the south or in the center.

A Study of Korea Sea East Trade Promotion Policy in East-North Asia (동북아지역 수산물 교역에 있어서 한국의 무역 진흥 전략)

  • 장영수;김병호;김기수;박명섭;정형찬;어윤양
    • The Journal of Fisheries Business Administration
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    • v.32 no.1
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    • pp.125-149
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    • 2001
  • The study tries to suggest policy proposals for enhancing competitiveness of our country as the base of fisheries logistics in East-North Asia. The study strongly recommends the adoption of the system of fisheries free trade area(FTA) to achieve the object under the analysis of structure of international fisheries trade in East-North Asian countries.

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A Study on International Cooperation System for Fisheries Resources Conservation & Management in the Northeast Asia (동북아 수역의 수산자원 보존관리 협력체제에 관한 연구)

  • Shim, Ho-Jin
    • The Journal of Fisheries Business Administration
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    • v.40 no.2
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    • pp.71-103
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    • 2009
  • This study is designed to propose the ways of the multilateral cooperation system for effective management of fisheries resources in the various overlapping zones established by bilateral fisheries agreements between Korea, China and Japan in North East Asia as semi-enclosed sea. It is necessary to build multilateral fisheries cooperation between Korea, China and Japan in North East Asia because conservation & management of transboundary fish stocks could not be guaranted effectively by the management of fisheries resources in the area where piled up the current-fishing-pattern zone, as white zone and the various grey zone as middle zone, and the interim measures zone of bilateral fisheries agreements between Korea, China and Japan are piled up. Fisheries management in Korea, China and Japan by the bilateral fisheries agreements in North East Asia is faced with difficulties manage fisheries resources. International relationship on fisheries is maintained by bilateral fisheries agreements based on UNCLOS. However fisheries resources are over-exploited and the recovery of the fisheries resources is very slow because proper conservation and management of transboundary fish stocks which article 63(1) of UNCLOS defines have not prepared yet. Thus close cooperation among the coastal States for a proper conservation and management of transboundary fish stocks is necessary. Since the transboundary fish migrate within the EEZs of two or more coastal States, there is a need to manage the fish stocks in the region between Korea, China and Japan through a multi-lateral mechanism at ccircumference area of the current-fishing-pattern zone as white zone. Coastal States must guarantee sustainable maintenance of transboundary fish stocks through the regional cooperation for a proper conservation & management because one coastal State alone could not guarantee conservation and management of fish stocks. Thus there is a need to build multilateral fisheries cooperation between Korea, China and Japan in North East Asia. There are many successful instances including the Barents' sea for a proper conservation & management of transboundary fish stocks. The Barents' sea is one of the best research object to study the regional cooperation for a conservation & management of transboundary fish stocks in North East Asia. In conclusion, it is necessary to build a multilateral fisheries cooperation system between Korea, China and Japan in North East Asia to conserve and manage transboundary fish stocks effectively. It seems desirable that the range of the area to conserve and manage fish stocks should may be any partial area in the current-fishing-pattern zone and interim measures zone between Korea and China, Jeju middle zone between Korea and Japan, interim measures zone of bilateral fisheries agreements between China and Japan.

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Eddy Kinetic Energy in the East Sea Estimated from Topex/Poseidon Altimeter Measurements

  • Cho Kwangwoo;Cho Kyu-Dae
    • Fisheries and Aquatic Sciences
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    • v.5 no.3
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    • pp.219-228
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    • 2002
  • Based on the five-year (October 1992 through September 1997) Topex/Poseidon altimeter measurements, we describe the statistical characteristics of the eddy variability in the East Sea in terms of sea surface height anomaly, slope variability, and eddy kinetic energy (EKE). The sea surface height anomalies in the East Sea are produced with standard corrections from Topex/Poseidon measurements. In order to eliminate the high frequency noise in the sea surface height anomaly data, the alongtrack height anomaly data was filtered by about 40 km low-pass Lanczos filter based on Strub et al. (1997) and Kelly et a1. (1998). We find that there exists a distinct spatial contrast of high eddy variability in the south and low eddy energy in the north, bordering the Polar Front. In the northwestern area $(north\;of\;39^{\circ}N\;and\;west\;of\;133^{\circ}E)$ from the Polar Front where the eddies frequently appear, the EKE is also considerabel. The high kinetic energy in the southern East Sea reveals a close connection with the paths of the Tsushima Warm Current, suggesting that the high variability in the south is mainly generated by the baroclinic instability process of the Tsushima Warm Current. This finding is supported by other studies (Fu and Zlontnicki, 1989; Stammer, 1997) wh.ch have shown the strong eddy energy coupled in the major current system. The monthly variation of the EKE in both areas of high and low eddy variability shows a strong seasonality of a high eddy kinetic energy from October to February and a relatively low one from March to September. The sequential pattern of wind stress curl shows resemblance with those of monthly and seasonal EKE and the two sequences have a correlation of 0.82 and 0.67, respectively, providing an evidence that wind stress curl can be the possible forcing for the monthly and seasonal variation of the EKE in the East Sea. The seasonality of the EKE also seems to correlate with the seasonality of the Tsushima Warm Current. There also exists the large spatial and interannual variabilities in the EKE.

On the Origin of the Tsushima Current Water

  • Lim, Du Byung
    • 한국해양학회지
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    • v.6 no.2
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    • pp.85-91
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    • 1971
  • The origin of the Tsushima Current water was investigated with a discussion on the western North Pacific Central Water. The Tsushima Current water is formed by the mixing of the Kuroshio surface water and the East China Sea water. The area where the mixing takes place remarkably is found to be the marginal region of the continental shelf of the East China Sea at the depth from 100 to 200 meters.

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Biogeographic Feature of North Korean Ecosystem (북한 자연생태계의 생물지리적 특성)

  • Kong, Woo-Seok
    • Journal of Environmental Impact Assessment
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    • v.11 no.3
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    • pp.157-172
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    • 2002
  • This work aims to collect a biogeographic informations on the biota, alpine ecosystem, nature reserves, forest ecosystem of North Korea, and also to accumulate a basic data on the current situation and problem of the natural ecosystem of North Korea for the preparation of future cooperation and exchange between South and North Koreas. The obtained findings are as follow. First, North Korean biota contains 18,013 species, and consists of 6,710 plant species, including 3,860 species of vascular plants. Secondly, urgent investigation on the biogeographically important arctic-alpine and alpine plants and ecosystem, those are known to be endangered due to environmental change and global warming, is required. Thirdly, the conservations of diverse nature in North Korea are conducted by the introduction of various systems, such as nature preservation region, reserves for plant, animal and sea bird, and natural monuments. Fourthly, out of 9.5 million hectares of forest, one million hectares have already faced forest denudation, thus caused lots of damages for forest ecosystem. Sharp decline of North Korean forest land are due mainly to the expansion of terraced dry-field farming and deforestation. Recovery of denudated forest land should be approached by both South and North Korean sides to solve the problem of shortage of foods and restoration of natural ecosystem of North Korea.

Study of the Tidal Currents in Sea Areas around Gyeong-In Waterway (경인아라뱃길 주변해역의 해수유동에 관한 연구)

  • Baek, Seung Hwa;Shin, Bum-Shick
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.9
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    • pp.5826-5834
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    • 2014
  • This paper examined the changes in flow patterns due to a blockage of tidal currents in the sea areas between Incheon North Port and Yeomha Channel when it would be influenced by the construction of the Incheon North Port Yeongjongdo dredged soil dumping ground and Incheon Bay tidal power plant. The numerical simulation was performed for three cases: before and after constructing the Incheon North Port Yeongjongdo dredged soil dumping ground and after the construction of the sea-dyke on the east side of the Incheon Bay tidal power plant. The simulation results showed that the tidal directions and currents velocity were similar before and after the construction of the Yeongjongdo dredged soil dumping ground. After the construction of the East Sea-dyke of Incheon tide power plant, however, the tidal currents patterns changed significantly due to flow blockage toward Gyeonggi Bay. The main flow was formed in the north-south direction, and the tidal currents velocity increased slightly on the downstream areas (A,B,C) of Hodo, which is the entrance of the Ara Waterway. The tidal currents at the mouth(D) of Yeomha Channel decreased significantly. The tidal currents of the west side of Se-eodo and the east side of the sea-dyke were rotary currents. The results of this study will provide basic data for the environmental impact assessment and the operation of the Gyeongin Ara Waterway.