• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.451-457
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• 2011

Large scale fishing ground can be made by upwelling flow. Recently the fishing ground development projects, using artificial upwelling by large structure under the sea, are in progress in Japan and Korea. In this study upwelling flow is simulated with FLOW-3D model. Using the movement of marker in FLOW-3D, the method for simulating upwelling of nutrients was experimented. The results show that FLOW-3D model can evaluate upwelling effect before starting real project.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.419-423
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• 2015

The flowing caused by artificial upwelling structure occurs ascending water flowing and vortex of rear side. In this moment, plentiful nutrient in the bottom water moves to the surface of the water and makes those plankton and fishing ecology promoted so that the fishing productivity can be enhanced. In this study, the changes of the upwelling flowing is included in consideration of the conditions of stratification by using CFD. In the conclusion, the closer upwelling effect is from the artificial upwelling structure, the better effectiveness comes out. Regardless of the conditions of stratification, only the upwelling feature from the bottom to the surface was shown up. But considering the conditions of stratification, the repeated flowing feature between upwelling and downwelling was verified.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.132-133
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• 2003

배타적 경제수역 및 UN 해양법 발효 등 조업 가능한 어장의 급속한 축소와 더불어 자국의 연안역 개발에 대한 중요성이 크게 부각되고 있다. 이에 따라 인위적인 수산자원 조성방법을 통하여 연안의 생산성을 향상시키고자 하는 노력의 일환으로 최근에는 해저면에 인공 구조물을 설치하여 국지적인 인공용승을 발생시키려는 연구가 시도되고 있다. (중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.21-27
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• 2008

Triangular structure is used as basic shape of artificial structures for generating the upwelling current in order to make rich fishing ground at sea. Artificial upwelling current could bring the deep sea water containing a lot of nutrients from the bottom up to the surface. The purpose of this study is to examine the flow characteristics around underwater triangular structure with various stratification parameter. An experimental study was carried out for the triangular structure model in the circulating water channel to investigate flow characteristics by flow visualization method. A velocity fields around the underwater structure were measured by particle image velocimetry(PIV). The experimental results showed that the upwelling effect at the back and upper region of the structure could be best when the water depth was 2 times of the structure height and the stratification parameter was approximately 3.0. These quantitative data will be useful to determine the functional efficiency cf artificial upwelling structures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.309-314
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• 2013

Temporal and spatial variations and species composition of ichthyoplanktons were investigated by Bongo net in a sea area with the construction of artificial upwelling structure at 13, June, 21 September, and 23 September in 2012. A total of fish eggs was 4,849 ind./$1,000m^3$, and fish larvaes was 641 ind./$1,000m^3$ in the study area. The common fish eggs was Engraulis japonicus which was composed of 57.5%, and unidentified I, II, III and IV were occurred with decreased number of individuals order. For fish larvaes, Pictiblennius yatabei, Repomucenus sp.A, sp.B and Scomber japonicus were dominated, however, other species were Engraulis japonicus, Konosirus puntatus, and unidentified I, II. Temporal variations of fish eggs and larvae were remarkable differed. Higher numbers of fish eggs and larvaes were July 2012, whereas those were lower at August 2012. Spatial variations of those were also significantly differed with higher numbers were at station 2 and 3 during study periods. The total number of fish eggs and larvae was about 4 fold against numbers of those in the compared area far from study area. These results indicated that higher numbers of fish eggs and larvaes were due to influx much more nutrients and food organisms with artificial upwelling.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.347-353
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• 2017

In this study, numerical experiments were conducted to identify distribution of rising flow and flux in the East Sea of Korea, where the coastal upwelling occurs. Temperature and salinity data from CTD observations and NIFS during summer 2013 were applied to the model. Numerical experiments were carried out with different wind speed (3, 6 m/s and 9 m/s) and direction (southerly and southwesterly), which represent the most frequent in summer conditions. As a result of calculation, upwelling flow rate was found to be highest in Pohang between five coasts(Hupo, Youngduk, Pohang, Ulsan and Busan). Comparing with southerly wind conditions, the rising flow rate is about 1.5 times greater when southwesterly wind was applied. Horizontal diffusion of the upwelling area is expected to have a speed of 17~22 km/day when a 9 m/s southwesterly wind is applied. If this wind continues over one week, a cold pool will be generated by upwelling that may reach to the Ulleung area.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.133-137
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• 2005

To investigated the variation of marine environments due to set up of artificial structure, we carried out field observations. High temperature and salinity waters were distributed clearly in the southeastern part of study area during summer season. The variation of current structure was also occurred around study area where artificial structure set up. In 2005 after set up of artificial structure, the nutrient concentration increased greater than that in 2002 before set up artificial structures. To illustrate the characteristics of marine environment due to set up of artificial structure, quantitative analyses on the effect of artificial structure are important.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.2
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• pp.100-106
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• 2017

Artificial upwelling structure has been set up in sea mount. Bottom water can upwelling euphotic zone. Plentiful nutrient included in bottom water could not only enhance primary production but also expect food chain reaction and gathering fish. This study explain flowing features subject to porosity changes according to the material and shape of artificial upwelling structure. As a result, the upward flux is getting decreased while the porosity is increasing. And it figured out when the upward flux was decreased, the downward flux was also decreased. Futhermore, it was confirmed that the best efficiency of upwelling flux was shown up when the porosity was 10% according to the volume of artificial upwelling structure in case of 20% of porosity, it also has a good efficiency in comparison with impermeable artificial upwelling structure. Therefore, to build the artificial upwelling structure, It is encouraged to design it less than 20% of porosity for the best performance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.2
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• pp.73-77
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• 2003

This study focuses on illustrating the effect of a hill on current filed at a channel, and the topographic effects of the hill were studied with various numerical experiments. The model experiments showed that stratification as well as bottom topography had influence on current fields around the hill. Due to stratification effect, Karman vortex formed behind the hill by bottom topography made effects on water movement only in the deep layer. The vortex reduced density field around the hill which resulted in the stratification in the water column, and which also resulted in the movement of isopycnic surface to deep layer both in front and back of the hill. The water in the back of the hill moved upward along ispycnic surface afterward. From these effects, velocity pattern in vertical direction around the hill showed opposite direction, downwrad in front of the hill and upward in the back. However, the upward flows did not seem to have any significant influence on the water conditions in the surface layer, even though strong upward flows were found on both side of the hill.

• 한국해양학회지
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• v.21 no.1
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• pp.13-24
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• 1986

The daily net primary production by phytoplankton in the southeastern sea of Korea in October 1985 ranged from 0.7 to 2.7 gCm$\^$-2/ d$\^$-1/ and averaged to be 1.3 gCm$\^$-2/ d$\^$-1/. Surface total chlorophyll ranged from 0.97 to 3.59mg chlm$\^$-3/. Primary production by nano-phytoplankton(〈20$\mu\textrm{m}$) ranged from 43 to 97% in the surface layer. Optimum light intensity(Iopt)was around 300 to 700${\mu}$Es$\^$-1/m$\^$-1/. Surface primary production from 9:00 to 15:00 h was evidently inhibited by strong light intensity beyond the Iopt. Phytoplankton near the base of euphotic zone(30-40m) showed extremely low Iopt suggesting adaptation to a low light environment. Since Iopt represents the history of light experience of phytoplankton at a given depth, the extent of variation in I of phytoplankton at different depth seems to be related to the in tensity of turbulence mixing in the surface mixed layer. From the present study, ammonium excretion by macrozooplankton (〉350$\mu\textrm{m}$) contributes from 3 to 19% of daily total nitrogen requirement by phytoplandton in this area. Calculation of upward flux of nitrate to the surface mixed layer from the lower layer, based on the simple diffusion model, approximates 3% of nitrogen requirement by phytoplankton. However, large portion of nitrogen requirement by phytoplankton remains unexplained in this area. In upwelling area near the coast, adjective flux might be the major source for the nitrogen requirement by phytoplankton. This study suggests that the major nitrogen source for the phytoplankton growth might come from the pelagic regeneration by nano-and micro-sized heterotrophic plandkon. Enhancement of primary production during the passage of the warm Tsushima Current is discussed in relation with nutrient dynamics and hydrlgraphic processes in this area.