• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.14-23
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• 2001

The characteristics of tidal circulation with Hyungsan River discharges in Youngil Bay by the numerical experiments is elucidated. For the simulation of tidal residual currents related to inflow by the river discharges in Youngil Bay located in the southeastern part of Korean Peninsula, the two-dimensional numerical experiment is peformed. The tidal elevation boundary conditions of the 4 main tidal harmonic constituents (M₂, S₂, K₁ and O₁) on the open boundary and river discharges at the river boundary are considered. The computed results obtained from numerical experiment showed good agreements with the field observation ones. The residual currents generally flow toward the inner bay through the western (Dalman-Gap) and central areas of the bay, and then the currents go toward the outer bay along the eastern shore (Changgi-Gap) of the bay with anti-clockwise circulation. Especially, in the numerical experiment without Hyungsan River discharges, these flow patterns are disappeared. Based on the results, it showed that the Hyungsan River discharges play the dominant role in the patterns of tidal residual currents. This flow pattern of tidal residual currents are important mechanism of water quality, material transport in Youngil Bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.431-437
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• 2002

In order to understand the spatiotemporal variation of water quality, an investigation on variation characteristics of water quality was conducted at 13 stations in Yongil bay from 1990 to 1998. The salinity in summer was relatively lower than that in other seasons and it have increased from inner bay to outside of the bay gradually. However, nitrate concentration in summer was relatively higher than that in other seasons, and it was the highest, up to $65.40\%$, among dissolved inorganic nitrogens, Nitrate concentration indicates the possibility of affecting by freshwater discharges to Yongil bay. Correlation analysis showed that salinity had a significantly good correlation with nitrate. This result suggested that inflow of river had an influence on increase of nitrate. The result of Principal Component Analysis (PCA) indicated that nitrate was major factor to influence the water quality in Yongil Bay.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.428-429
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• 2001

어류상에 대한 연구는 연안 어족자원의 정량적 평가와 효율적인 자원관리를 위하여 필요하며. 또한 연안어장에 어획량의 지속적인 확보와 자원량 예측평가를 가하기 위하여 자료를 확보하는데 그 목적이 있다. 우리나라 동해안을 중심으로 지금까지 영일만 연안 정치망 어장에 출현한 어류군집의 종조성 및 양적변동(한 등, 1997), 삼중자망에 채집된 동해 홍해 연안어류의 종조성(황 등, 1997, 영일만 저어류 종조성의 계절 변동(이, 1999) 둥의 연구가 있다. (중략)

• 한국해양학회지
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• v.7 no.2
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• pp.74-85
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• 1972

This paper studied the grain size distribution of bottom sediments of Yeongil Bay which is located at the southeastern part of the Korean Peninsula. Sixty four samples collected with snapper and dredger are analyzed by roe Tap Sieve Shaker and Pipette Method. The moment parameters are calculated with the method of Friedman(1961). Most samples are composed of sand size sediments and a few samples are composed of silt and clay. The Yeongil Bay can be divided into gravel-granule zone, sand zone, and silt-clay zone. The sediments near Yeonam- Dong and Hyongsan river are moderately sorted and others are very poorly sorted according to scheme of Friedman91962). In general, sorting values are ranged from 1.0 to 3.5. The samples near Janggigap and Masin-Dong show negative and others show positive skewness values. Skewness values are ranged from -1 to 2. All samples show the leptokurtic distribution except for the samples near Masin- dong and at the deepest place near Janggigap. Kurtosis values are ranged from -1.5 to 21.9. The samples of gravel-granule zone contain more than 50% and those of silt-clay zone contain less than 50% of CaCO$\_$3/. Four different colors, black, yellow, brown and gray, are shown in the sediments of Yeongil Bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.512-519
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• 1999

Seasonal variation in species composition and abundance of demersal fish in Yongil Bay were determined by analyzing samples collected using an otter trawl from January to October 1991. Of 59 species identified, Repomucenus lunatus, Tridentiger trigonocephalus, Repomucenus heguenini, Ammodytes personatus and Sillago japonica were dominated in abundance. Number of spiecies and biomass were low in winter and high in spring and summer. Species composition did not show spatial variation but showed seasonal variation. Number of spicies, abundance in number of individuals ($630 inds./10^3\;m^2$) and in biomass ($13,131g/10^3\;m^2$), and species diversity (2.00-2.54) of fish in Yongil Bay were higher than those of the coastal waters in the Yellow Sea or in the South Sea of Korea.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.57-65
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• 2004

In order to determine the effect of fresh water inflow from the Heongsan river on the changes of water quality in the Yeongil Bay (Korea), the seasonal changes of water temperature, salinity, chemical oxygen demand (COD), dissolved inorganic nitrogen(DIN) and phosphate phosphorus ($PO_4$-P) concentrations were examined using the data set obtained five fixed points of Yeongil Bay from 1998 to 2000. The distributions and changes of COD and concentrations of total inorganic phosphorous (TIP) and nitrogen (TIN) at three points Heongsan river, were also compared with those of Yeongil Bay. Based on the correlations of DIN and $PO_4$-P, it was found that the inflow of freshwater affected on the water quality of Yeongil Bay. Such a complicacy was confirmed by the prominent differences in n few water quality measures between Site 1(the innermost area) and Site 5 (the mouth of the bay). The negative correlations in $\Delta N/\Delta P $ at sites 1, 2 and 3 of the inner-part of the bay also indicated a large effect of freshwater inflow on the water quality of the bay. The extremely low atomic ratio of an average of 6.4 in $\Delta N/\Delta P $ compared to the Redfild ratio suggested that the DIN was depleted in the overall bay system. In contrast, it was inferred that the excessive PO$_4$-P concentration was due to the inflow of freshwater from the Heongsan river.

• Geophysics and Geophysical Exploration
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• v.24 no.3
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• pp.78-88
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• 2021

Owing to the abnormal weather conditions due to global warming, carbon capture and storage (CCS) technology has attracted global attention as a countermeasure to reduce CO₂ emissions. In the Pohang CCS demonstration project in South Korea, 100 tons of CO₂ were successfully injected into the subsurface CO₂ storage in early 2017. However, after the 2017 Pohang earthquake, the Pohang CCS demonstration project was suspended due to an increase in social concerns about the safety of the CCS project. In this study, to reconfirm the structural suitability of the CO₂ storage site in the Pohang Basin, we employed seismic imaging based on reverse-time migration (RTM) to analyze small-scale ocean-bottom seismic data, which have not been utilized in previous studies. Compared with seismic images using marine streamer data, the continuity of subsurface layers in the RTM image using the ocean-bottom seismic data is improved. Based on the obtained subsurface image, we discuss the structural suitability of the Pohang CO₂ storage site.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.63-70
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• 1999

The optimum sampling area which can be applied to the benthic community study is estimated from large survey data in the Songdo tidal flat and subtidal zone of Youngil Bay, Korea. A total of 250 samples by 0.02 $m^2$ box corer for the benthic fauna in Songdo tidal flat and 50 samples by 0.1 $m^2$ van Veen grab in Youngil Bay were taken from the total sampling area of 5 $m^2$. It was assumed that the sampling area could contain sufficient information on sediment fauna, if cumulative number of species, ecological indices, and similarity index by cluster analysis reflect the similarity level of 75% to those found at total sampling area (5 $m^2$). A total of 56 and 60 species occurred from Songdo tidal flat and Youngil Bay, respectively. The cumulative curve of the species number ($N_{sp}$) as a function of the sampling area (A in $m^2$ ) was fitted as $N_{sp}=37.379A^{0.257}$ ($r^2=0.99$) for intertidal fauna and $N_{sp}=40.895A^{0.257}$ ($r^2=0.98$) for subtidal fauna. Based on these curves and 75% of similarity to the total sampling area (5 $m^2$), the optimum sampling area was proposed as 1.6 $m^2$ for the intertidal and 1.5 $m^2$ for the subtidal fauna. Ecological indices (species diversity, richness, evenness and dominance indices) were again calculated on the basis of species composition in differently simulated sample sizes. Changes in ecological indices with these sample sizes indicated that samplings could be done by collecting fauna from < 0.5 $m^2$-1.5 $m^2$ on the Songdo tidal flat and from < 0.5 $m^2$-1.2 $m^2$ in Youngil Bay. Changes in similarity level of all units of each simulated sample size showed that sampling area of 0.3 $m^2$ (Songdo tidal flat) and 0.6 $m^2$ (Youngil Bay) should be taken to obtain a similarity level of 75%. In conclusion, sampling area which was determined by cumulative number of species, ecological indices and similarity index by cluster analysis could be determined as 1.5 $m^2$ (0.02 $m^2$ box corer, n=75) for Songdo tidal flat and 1.2 $m^2$ (0.1 $m^2$ van Veen grab, n=12) for Youngil Bay. If these sampling areas could be covered in the field survey, population densities of seven dominant species comprising 68% of the total faunal abundance occurring on Songdo tidal flat and six species comprising 90% in Youngil Bay can be estimated at the precision level of P=0.2.

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.121-121
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• 1998

• Proceedings of the Korea Water Resources Association Conference
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• 1995.05a
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• pp.527-532
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• 1995