• Journal of Wind Energy
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• v.13 no.2
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• pp.42-52
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• 2022

In this paper, we propose a time-series generation methodology using a generative adversarial network (GAN) for long-term prediction of wind and sea conditions, which are information necessary for operations and maintenance (O&M) planning and optimal plans for offshore wind farms. It is a "Conditional TimeGAN" that is able to control time-series data with monthly conditions while maintaining a time dependency between time-series. For the generated time-series data, the similarity of the statistical distribution by direction was confirmed through wave and wind rose diagram visualization. It was also found that the statistical distribution and feature correlation between the real data and the generated time-series data was similar through PCA, t-SNE, and heat map visualization algorithms. The proposed time-series generation methodology can be applied to monthly or annual marine weather prediction including probabilistic correlations between various features (wind speed, wind direction, wave height, wave direction, wave period and their time-series characteristics). It is expected that it will be able to provide an optimal plan for the maintenance and optimization of offshore wind farms based on more accurate long-term predictions of sea and wind conditions by using the proposed model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.10 no.1
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• pp.1-18
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• 1974

Some coastal oceanographic investigations in Kwang Yang Bay were carried out bimonthly from April to September (The first half period of the research project) in 1974. The behaviour of the waters, distributions of water temperature and salinity and diffusion characteristic by dye release experiments in the bay are studied for the problems of practical importance in connection with water pollution. Velocities and directions of tidal currents at five fixed stations were observed. And dye diffusion experiment was also carried out on the sea. According to the results from this study, the salinity of the water is lower, ranging from about $28\;\textperthousand\;to\;32\textperthousand$, on all over the surface in the bay with the cause that the fresh water flows in from the Sumjin river. Diffusivities in this sea by means of Rhodamine B diffusion elliperiment were $785.6\;{\times}\;10^2\;\textrm{m}^2/sec$ in major axis, $15.6\;{\times}\;10^2 \;\textrm{m}^2/sec$/sec in minor axis in the direction on patch after 30 minutes from the dye release.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.77-85
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• 2002

In the southern sea of Korea and the areas of Tsushima warm currents the relationship between the distributions of eggs and larvae of anchovy (Engraulis japonica) and oceanic conditions was examined on July and August 1997, The south Korean coastal waters, the water temperature of below $20\~23^{\circ}$ and the salinity of above 33.0 (PSU), the mixed waters between the south Korean coastal waters and the Tsushima warm currents, $21\~25^{\circ}$ and $32.0\~32.5$ and the Tsushima warm currents, above $26^{\circ}$ and below 31.5 were distributed at the surface layer. The Tsushima warm currents were distributed at the northeast of Jeju Is. and off the southern sea of Korea. As an appearance of warm streamer, the mixed waters were intruded into the coastal areas of Komun Is.$\~$Sori Is. and Sori Is.$\~$Yokji Is.. Approximate paths of surface water by the drift card experiments were similar with the intrusions of the warm water identified from the water temperature and salinity distributions. The distributions of chlorophyll concentration were consistent with the distributions of water temperature and salinity, Anchovy eggs and larvae were mostly distributed at Komun Is., Yokji Is, and the southwest of Koie Is. where chlorophyll concentrations were high and cyclonic circulations by the warm water intrusions (warm streamers) were formed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.2
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• pp.153-165
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• 1995

The fluctuations of catches in set nets around Kyeongbuk Province, the eastern coast of Korea, were analyzed and investigated by on the values of CPUE(Catch Per Unit Effort per hauling), and composition of dominant species caught from 1985 to 1989. Annual CPUE values were fluctuated every year, but their trends were decreased year by year, When the values were evaluated by species, the trends of annual catches were shown decreasing in file fish(Auteridae), mackerel(Scomber japonicus), tuna(Thunnus Thynnus), rock fish(Sebastes schlegelid) and yellowtail(Seriola quinqueradiata), increasing in sardine(Sardinops melanosticta), jack mackerel(Trachurus japonicus), and herring(Clupea pallasi), and similar in squid(Todarodes pacificus) and cuttle fish(Sepiidae). The main fishing season evaluated by monthly CPUE was estimated from August to November with a little difference by regions : from August to November at Chukpyon and Kanggu, from September to November at Chuksan and Kampo, and August to December in Hupo. When the DPUE values were analyzed by species, the main fishing seasons were quite different by species. Mackerel, jack mackerel, tuna, yellowtail, and rock fish were caught mainly from September to October, file fish and squid from November to January, sardine from April to May, herring in May, and cuttle fish in April. Annual catches were shown highest level in file fish and revealed higher by sardine, jack mackerel, mackerel, squid, tuna, and yellowtail in order. But the highest catches among each species were different with seasons, and that from January to July was sardine, from November to December file fish. The main migrating seasons of file fish, mackerel, squid, tuna, and cuttle fish at Chukpyon were a little earlier than at other regions. Though the migrating seasons of jack mackerel and tuna were almost same in every regions, that of sardine were shown 3 month's difference according to regions. In the year when the warm currents were stronger than those of the normal year and their isotherms were formed from the north to south along the eastern coastal line, the annual fish catches in set net were show higher levels.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.147-148
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• 2003

동해안의 강릉 연안에 자생하는 토종 다시마인 개다시마는 산업적으로 개발의 여지가 매우 크다. 그러나 천연 자원량에 의존하고 있는 가공산업은 해황에 따라 원료 공급이 좌우되는 불안정성을 가지고 있어서 이 식물의 산업적 생산량을 확보하기 위한 방안으로 대량양식의 필요성이 대두되고 있다. 본 연구는 동해안 토종 다시마인 개다시마의 종묘생산기술 개발을 위해서 항온배양기와 실내수조배양을 실시하고 바다 가이식 양성에 의한 환경적응성 실험을 수행하였다. 연구 방법은 2001년 10월에 강릉연안 수심 20m에서 분포하는 개다시마 군락의 모조로부터 유주자액을 받아 온도 5, 10, 15, 20, $25^{\circ}C$, 조도 40, 80, 120 $\mu$mol m$^{-2}$ s$^{-1}$의 조건에서 6주간 정치배양하였다. 유주자의 발아 및 아포체 생장 실험 이후 바다 가이식 및 양성실험은 2002년 1~2월까지 1개월간 실시하였다. 유주자의 발아 및 아포체 형성은 1$0^{\circ}C$, 120$\mu$mo1 m$^{-2}$ s$^{-1}$에서 배양 2주만에 가장 먼저 아포체의 발아가 관찰되었으며, 이후 15$^{\circ}C$와 5$^{\circ}C$에서 순차적으로 아포체의 발아가 이루어졌다. 2$0^{\circ}C$는 80, 120$\mu$mol m$^{-2}$ s$^{-1}$에서 소수의 아포체만이 관찰되었으며, $25^{\circ}C$에서는 아포체가 형성되지 않았다. 아포체는 1$0^{\circ}C$에서 가장 좋은 생장을 보였고, 15$^{\circ}C$와 1$0^{\circ}C$에서는 비슷한 생장을 나타냈으며, 2$0^{\circ}C$에서는 80$\mu$mol m$^{-2}$ s$^{-1}$에서만 아포체의 형성이 관찰되어 가장 낮은 생장을 보였다. 동일 온도에서는 조도에 따른 생장의 차이가 많이 났는데, 40$\mu$mol m$^{-2}$ s$^{-1}$에서 가장 좋은 생장을 나타냈다. 80과 120$\mu$mol m$^{-2}$ s$^{-1}$에서는 120$\mu$mol m$^{-2}$ s$^{-1}$이 약간 좋은 생장을 보였지만 큰 차이는 나지 않았다. 생장이 가장 좋은 조건은 1$0^{\circ}C$, 40$\mu$mol m$^{-2}$ s$^{-1}$으로 엽장 1.28mm까지 생장했다. 전체적으로 수심이 깊은 곳에 서식하는 특성상 저수온과 저조도에서 좋은 생장 경향을 보였다. 실내배양을 통해 얻은 엽장 약 1~2mm의 종묘를 2002년 1월말에 삼척 호산에 위치한 바다 양성장에서 종묘들과 함께 2주간 수심별로 가이식(수온 12$^{\circ}C$)을 실시한 결과, 수심 1m에서 좋게 나타나 엽장이 약 5mm정도 생장하였다. 수심 0m에서는 강한 조도에 의해 엽상체가 사그라드는 기형이 나타났으며, 수심 5m에서는 엽상체의 기형이나 생장의 차이는 없었지만, 색택이 약간 바랜 것을 볼 수 있었다. 종합적으로 볼 때 종묘의 관리나 생장에는 수심 1~2m가 양호할 것으로 생각된다. 바다 가이식을 통해 엽장 5mm의 종묘로 생장시킨 후 바로 본양성장에 씨줄감기를 하여 양성을 실시하였다 양성 1개월 후 엽상체는 약 2~3cm, 최대 4~5cm까지 생장하였다. 이를 통해 강릉연안 토종 다시마인 개다시마에 대한 종묘 생산과 대량 양성의 가능성을 확인하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.39-46
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• 2010

Sounding data is the essential source for the safety of ships navigation system, and fundamental to the reasonable usage and maintenance of the ocean as well. As IT tech, positioning equipment such as GPS and INS, echo sounder are developed, recently, the precise submarine topography database bas been built by Multi-Beam Echo Sounder. However, MBES data includes some inevitable error caused by several factor, and some data have errors where the terrain is wobble. The error, which causes the $moir\acute{e}$ pattern error is the main factor hindering the accuracy of MBES data results, and therefore it is necessary to figure out the main cause of the error for the improvement of the accuracy by removing error data. On this research, the main cause of the error data is studied by analyzing motion sensor value of data including the $moir\acute{e}$ pattern error. Thus, as the result of examination, it turns out that the $moir\acute{e}$ pattern error is related to the standard deviation of Roll, and error data values are results of the non-correspondence between Swath data and Roll values caused by the drastic change of Roll values. Accordingly, the error data is removed by comparing between the gradient of Swath data and Roll values. Finally, as the result of removing error data, it is expected to be able to estimate the quality of MBES using the standard deviation of Motion sensor's Roll value, and calculate the additive error factor, which minimize non-corresponding data, and also this research must be contributed to improve the accuracy of sounding for small vessels with lots of motion in the bad circumstance for navigation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.327-333
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• 2013

In order to see the stratification phenomenon in the coastal area induced by oceanographic conditions of the open sea, we analyzed the CTD (Conductivity-Temperature-Depth) data taken from the oceanographic survey on February 16~28, 2013. The stratification in Jukbyun coast was stronger than those of Sokcho and Gampo coast. Jukbyun line (104 line in the Serial Oceanographic Observation of National Fisheries Research and Development Institute) showed the anticyclonic eddy in the vertical distribution of temperature. The isotherm of $10^{\circ}C$ was concaved to the depth of 200 m in the middle station (station no. 9) of the line 104. It showed above $4^{\circ}C$ in positive temperature anomaly in the depth of 100~200 m in the middle station (station no. 9) of the line 104. This positive temperature anomaly was stretched to the coastal area with shallower depth. It is suggested that the stratification in Jukbyun coast was resulted from the onshoring of the Ulleung warm eddy. The movement of warm eddy may be act as a block to migration of cold water fishes like cod.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.263-274
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• 2020

In the Southeast Sea of Korea, a cold water mass is formed intensively in summer every year, causing frequent abnormal sea conditions. In order to analyze the spatial changes of sea surface temperature distribution in this area, ocean fields buoy data observed at Gori and Jeongja and reanalyzed sea surface temperature(SST) data from GHRSST Level 4 were used from June to September 2018. The buoy data were used to analyze the time-series water temperature changes at two stations, and the GHRSST data were used to calculate the daily SST variance and weighted mean center(WMC) across the study area. When the buoy's water temperature was lowered, the variance of SST in the study area trend to increase, but it did not appear consistently for the entire period. This is because GHRSST is a reanalysis data that does not reflect sensitive changes in water temperature along the coast. As such, there is a limit to grasping the local small-scale water temperature change in the coast or detecting the location and extent of the cold water zone only by the statistical variance representing the SST change in the entire sea area. Therefore, as a result of using WMC to quantitatively determine the spatial location of the cold water mass, when the cold water zone occurred, WMC was located in the northwest sea area from the mean center(MC) of the study area. This means that it is possible to quantitatively identify where and to what extent the distribution of cold surface water temperature appears through SST's WMC location information, and we could see the possibility of WMC's use in detecting the scale of cold water zones and the extent of regional spread in the future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.2
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• pp.44-53
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• 1989

In order to grasp the characteristics of a fishing ground at yeosu bay, the fluctuation in condition of the coast and that in catch by pound nets in the coast were investigated respectively. The results obtained are summarized as follows: 1. The water temperature in spring and summer was higher at the coast side than off shore, but in autumn and winter took the reverse. 2. The salinity was higher in spring and winter than in summer and autumn. A lower salinity zone was found at the Dolsan Do coast and higher ones were made off shore. 3. A eddy current was found at the Dolsan Do coast and a thermocline were made at the depth of 30 to 40 m in summer. But in autumn and winter the water became homogeneous. 4. The annual catch by the pound net was highest in 1984 and then decreased gradually. The monthly catch was highest in June and then decreased gradually. 5. The catches seemed to increase with the sea water temperature and salinity, and great catch was shown in 21$^{\circ}C$ to 27$^{\circ}C$ and 33.80% to 34.00%. 6. The component rate of fishes was 28.4% in spanish mackerel, 17.9% in anchovy, 19.5% in horse mackerel, 21.0% in sardine, 7.2% in hairtail, and 1% in common mackerel. 7. The fishes appeared continuously on way of fishing operation were spanish mackerel, hairtail, Yellow talil, crab, etc. An anchovy and sardine were caught mainly from March to July or August, horese mackerel and common mackerel from May to November. but puffer, swell fish, saury and filefish were caught mainly from April to October. 8. The sum of catch was largest in June, at which the wind direction was NE to SSW, the speed below 3.2m/sec, the atmospheric pressure below 1008mb, and precipitation beyond 154mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.81-89
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• 1982

In order to analyze the formation mechanism for the fishing ground of the Gang-dal-i, the relationship between the fish grounds of the Gang-dal-i and the oceanographic structure of the East China Sea and the Yellow Sea is investigated by using the data of the catches of stow net fishery (Fisheries Research and Development Agency, 1970-1979) and the oceanographic observation data (Japan Meteorological Agency). The main fishing grounds of the Gang-dal-i concentrated in the adjacent seas of Daeheugsan island and Sokotra Rock. In these areas, the fishing conditions are generally stable, because about 70% of the total catch of the Gang-dal-i for the ten years is occupied, CPUE also is relatively great, and the coefficients of variation of the catches are relatively small as 0.9 to 1.4. The main fishing periods are roughly from February to March and June to July, and the years of good catches are from 1974 to 1976. In general, the main fishing grounds are formed in the marginal areas of the Yellow Sea Bottom Cold Water. They are the frontal areas in which the Yellow Sea Bottom Cold Water is intermixed with the Yellow Sea Warm Current. The range of the temperature and the salinity in these regions are from 10 to 13$^{\circ}C$ and 32.5 to 34.4$\textperthousand$, respectively.