• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.313-319
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• 2007

Long term wave climate of both extreme and operational wave height is essential for planning and designing coastal structures. Since the availability of the field wave data for the waters around Korean peninsula is limited to provide a reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. In this paper, a set of deep water wave data obtained from KORDI(2003) were analyzed for extreme wave heights. These wave data at 67 stations off the Korean coast from 1979 to 1998 were arranged in the 16 directions. The probability distributions considered in this research were the FT-I and Weibull distribution. For each of these distributions, the method proposed by Goda(2004) was applied to estimate the parameters. For judgment of best fitting, MIR criterion proposed by Goda and Gobune(1990) was used. FT-I distribution which best fits to the 886 data, while Weibull(k=0.75) 81 data, Weibull(k=1.00) 105 data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.659-664
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• 2010

This study investigated the distribution of spotted seals, Phoca largha, inhabiting the coast of Baekryongdo. Monitoring of spotted seals in Baekryongdo was conducted between June 2006 and November 2008, using a 5-ton fishing vessel 1hour before low tide. The monthly maximum number of observed seals was 274 in September 2006, 139 in September 2007, and 213 in August 2008. Average observed monthly counts were largest in August and September. Relatively more spotted seals were observed when there were few cloudy days and plenty of sunshine. Bycatch, stranding, and observations of spotted seals have been reported along the coast of the Korean peninsula since 2000, and spotted seals were observed four times in the western coastal region, three times in the southeastern region, and 12 times on the east coast. This suggests that spotted seals inhabiting Baekryongdo migrate to the East Sea via the West and South seas as individuals or in groups.

• Journal of Species Research
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• v.10 no.3
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• pp.276-286
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• 2021

We performed a taxonomic study on Korean Pacificincolidae (Bryozoa: Cheilostomata) with the materials collected from 39 localities(ports, intertidal and subtidal zones) in the coastal seas of South Korea from 1981 to 2020. Korean Mucronella perforata reported by Rho and Seo (1985) turned out to be not Pacificincola perforata, but Primavelans glabricollaris n. sp. based on morphological data. Pacificincola perforata, which was transferred from Mucronella perforata (Okada and Mawatari, 1937), is also added to the Korean fauna. This study is the first to use mitochondrial 16S rRNA gene sequences to study the family Paficincolidae. The NJ analysis also reconfirmed the validity of the genus Primavelans, established on the basis of the early astogeny by De Blauwe in 2006, with the mitochondrial 16S rRNA sequences. The inter-genetic distance among two species belong to the Pacificincolidae was in the range of 13.39±1.83 mm. Primavelans glabricollaris n. sp. is thus distinguished from Pacificincola perforata with both morphological and molecular data. A new species, Primavelans glabricollaris, and a new record, Pacificincola perforata from Korea are herein described in detail and illustrated by scanning electron microscopy.

• Journal of Species Research
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• v.11 no.3
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• pp.180-187
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• 2022

We found three fouling bryozoans from the materials collected from seven localities (ports, yacht marina, intertidal and subtidal zones) in the coastal seas of South Korea from 2003 to 2021. These three species, Thalamoporella californica (Levinsen, 1909), Scruparia ambigua (d'Orbigny, 1841), and Tricellaria inopinata d'Hondt and Occhipinti Ambrogi, 1985, and one genus Scruparia Oken, 1815 are newly added to the Korean bryozoan fauna. Of the three species, Scruparia ambigua and Tricellaria inopinata are cosmopolitan or widespread, and Thalamoporella californica is from the East Pacific Ocean in tropical/temperate water. It seems that some of the previously reported T. occidentalis in Korea have a high probability of being T. inopinata. In this study, some Tricellaria occidentalis reported by Seo (2005) are synonymized into T. inopinata. A total of 77 species of fouling bryozoans has been reported in Korea, with three new bryozoans resulting from this study. Descriptions and illustrations of the three fouling bryozoans using scanning electron microscopy are provided in this study.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.131-139
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• 2014

Infra-gravity waves (IGWs) with a period of 1~3 minutes are a factor that directly influences the motion analysis of moored ships inside a harbor and longshore sediment transport analysis. If significant levels of IGWs from far seas are transferred to a harbor and amplified, they may cause downtime of large ships and induce economic loss. In this study, transfer characteristics of the IGWs intruding from outside to inside Pohang New Harbor were analyzed using statistical analysis and transfer function of wave data measured at both outside and inside the harbor for around 5 years. Transfer characteristic analysis was limited to events where IGWs had wave heights above 0.1 m. The wave height distribution of inside the harbor was similar to that of outside the harbor, while the wave period variance of the former was larger than that of the latter. The parameters of the transfer function was optimally estimated according to each event. The estimated average RMS error of the wave height inside the harbor was around 0.013 m. The estimated parameters had a strong correlation with the linear combination information of IGW wave height, period, and direction (R = 0.95). The transfer function suggested in this study can quickly and easily estimate information on IGWs inside the harbor using IGW information predicted beforehand, and is expected to reduce damage due to unexpected restrictions on harbor usage.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.5
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• pp.482-490
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• 2008

For a coastal or harbor structure design, one of the most important environmental factors is the appropriate extreme highest tide level condition. Especially, the information of extreme highest tide level distribution is essential for reliability design. In this paper, 23 set of extreme highest tide level data obtained from National Oceanographic Research Institute(NORI) were analyzed for extreme highest tide levels. The probability distributions considered in this research were Generalized Extreme Value(GEV), Gumbel, and Weibull distribution. For each of these distributions, three parameter estimation methods, i.e. the method of moments, maximum likelihood and probability weighted moments, were applied. Chi-square and Kolmogorov-Smirnov goodness-offit tests were performed, and the assumed distribution was accepted at the confidence level 95%. Gumbel distribution which best fits to the 22 tidal station was selected as the most probable parent distribution, and optimally estimated parameters and extreme highest tide level with various return periods were presented. The extreme values of Incheon, Cheju, Yeosu, Pusan, and Mukho, which estimated by Shim et al.(1992) are lower than that of this result.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.173-184
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• 2016

This study was carried out to understand the characteristic distributions of water temperature and salinity in accordance with seasons atound the Tongyeong and Geoje, based on a cluster analysis. Water temperatures in coastal areas were $1-2^{\circ}C$ higher than those in open seas when in the spring, autumn and winter. In particular, a south-northward isothermal line was established at the bottom layer in the winter of 2014, unlikely to the surface layer. In addition, a south-northward isohaline was also established at the bottom layer in the winter of 2013. Therefore, we recognized that a moving pattern of water masses has also a difference since forming directions of those lines were not equivalent with each other between the surface and bottom layers. In contrast, stratification appeared in the summer with a roughly difference of water temperature of $10^{\circ}C$ and a salinity of 2-10 psu between the layers. A cluster analysis indicated that the southeastern coastal waters have three distinct water masses, even though some complicated situations exist due to the seawater inflow from the outside. However, the result of a cluster analysis turned out quite reasonable because the result of a regression analysis proved that it is appropriate, just except for the timing of a south-northward front formation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.3
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• pp.115-124
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• 1997

We measured the variance of eddy diffusion and associated ‘diffusion coefficients’ in coastal regions of Korea by observing the separation distances among multiple drifters deployed simultaneously at the same initial position. The variance of eddy diffusion was found to be proportional to $t^m$, where t is the time and m is a non-integer scaling exponent between 1.5 and 3.5. The observed scaling exponent of eddy diffusion cannot be reproduced by diffusion models employing constant eddy diffusivity. In this study, we applied fractal theory in simulating exponential increase of variance of eddy diffusion. We employed the fGn(fractional Gaussian noise) as a ‘modified’ random walks corresponding to the oceanic eddy diffusion. The variance of eddy diffusion, which corresponds to the fBm(fractional Brown motion) of our diffusion model, is proportional to $t^{2H}$, where H is Hurst scaling exponent. The temporal increase of the variance. with scaling exponent between 1 and 2, was successfully reproduced by our fractal diffusion model. However, our model cannot reproduce scaling exponent greater than 2. The scaling exponents greater than 2 are associated with the velocity shear of the mean flow.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.3
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• pp.36-41
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• 1986

Uederwater ambient noise was measured at the set net in the Neung-Po Eay. The environment characteristics depend upon oceanographic conditions of sound propagation and its implication on the source of ambient noise. The results of measurement and analysis were as follows: 1. The frequency of the maximum noise level of two passenger. vessels was around 300 Hz. The spectrum level of the fast vessel (the Air-Ferry) was lower than the little slow vessel (the Olympic) between 50-150 Hz in frequences. 2. The spectrum level of the surface in the playground of the set net was lower than the deeper water till 500 Hz, but over that frequency the level was getting lower as the depth was deep. 3. The spectrum level outside the bag of the set net was greater than the inside between 50 and 700 Hz, but over 1,500 Hz the level inside the bag was higher than the outside. 4. The spectrum level of the outside of the breeding tank was higher than the inside in the daytime. However at night opposite phenomenon occurs.

• 한국해양학회지
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• v.25 no.2
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• pp.49-61
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• 1990

The family Corycaeidae in the neighbouring seas of Korea was taxonomically studied based on the zooplankton samples collected in August, 1986. In this study, nine species belonging to two genera and three subgenera of the Corycaeidae were identified and described with illustrations; Corycaeus (Corycaeus) speciosus, G.(C.) crassiusculus, C. (Ditrichocorycaeus) affinis, C.(D.) andrewsi, C.(D.) erythraeus, C.(Onychocorycaeus) pacificus, c.(O.) catus, C.(O.) agilis, and Farranula gibbula. The distribution patterns of these species showed that C.(D.) affinis appeared to be and indicator species of the coastal waters, and C.(C.) speciosus, C.(C.) crassiusculus, c.(O.) catus, C.(D.) andrewsi, and Farranula gibbula appeared to be indicator species of the warm-oceanic waters.