• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.14-22
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• 2017

The frequency and scale of natural disasters due to the abnormal climate phenomena caused by global warming have being increasing all over the world. Various natural disasters, such as typhoons, earthquakes, floods, heavy rain, drought, sweltering heat, wind waves, tsunamis and so on, can cause damage to human life. Especially, the damage caused by natural disasters such as the Earthquake of Japan, hurricane Katrina in the United States, typhoon Maemi and so on, have been enormous. At this stage, it is difficult to estimate the scale of damage due to (future) natural disasters and cope with them. However, if we could predict the scale of damage at the disaster response level, the damage could be reduced by responding to them promptly. In the present study, therefore, among the many types of natural disaster, we developed a function to estimate the damage due to wind waves caused by sea winds and waves. We collected the damage records from the Disaster Report ('91~'14) published by the Ministry of Public Safety and Security about wind waves and typhoons in the western coastal zone and, in order to reflect the inflation rate, we converted the amount of damage each year into the equivalent amount in 2014. Finally, the meteorological data, such as the wave height, wind speed, tide level, wave direction, wave period and so on, were collected from the KMA (Korea Meteorological Administration) and KHOA (Korea Hydrographic and Oceanographic Agency)'s web sites, for the periods when wind wave and typhoon damage occurred. After that, the function used to estimate the wind wave damage was developed by reflecting the regional characteristics for the 9 areas of the western coastal zone.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.236-248
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• 2019

We investigated occurrence and molecular phylogeny of the toxic epiphytic dinoflagellate Ostreopsis at seven sampling sites in the coastal waters off Jeju Island of Korea in April, 2017. During the sampling period, surface water temperature ranged from 15.7 to $18.3^{\circ}C$ and salinity was relatively constant, ranging from 33.4 to 34.9. Of a total of 13 macroalgal species collected from all sampling sites, Ostreopsis cells were observed from 8 macroalgal species and the highest cell abundance ($157.5cells\;g^{-1}$) was recorded on the red alga Grateloupia filicina at St. 6. LSU rDNA D8/D10 sequences of all Korean Ostreopsis strains isolated from the 4 sampling sites were 100% identical. Molecular phylogentic analyses (BI and ML) inferred from LSU rDNA alignment showed that the Korean Ostreopsis strains placed into the previously described the Ostreopsis sp. 1 clade, which contained strains isolated from the temperate coastal waters of Japan. The Korean Ostreopsis sp. 1 strain grew in a wide range of temperature ($10-30^{\circ}C$) and salinity (25-30), with its maximum growth rate of $0.49d^{-1}$ at $25^{\circ}C$ and salinity of 30, indicating that they can be tolerated in temperate areas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.3
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• pp.129-137
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• 1989

Sand fish, Arctoscopus japonicus (Steindachner) is distributed in the coastal waters of East Sea of Korea, Japan, and Alaska. On December 1, 1987, matured adult of sand fish were collected from the shore of Ok-kye, Myongju-gun, Kangwon-do, Korea. The authors carried out artificial insemination on boat. The fertilized eggs were incubated and the larvae were reared in laborato교. The eggs of this species were demersal and adhesive, and their diameter were varied within $3.1\~3.4$mm (mean 3.3 mm, n= 10). They have a number of small oil globules. The spawned eggs in nature were formed the egg mass which were measured ca. 4 m in dia-meter. The hatching took place in 65 days after fertilization at the water temperature of $8.7\~12.3^{\circ}C$. The newly hatched larvae were $8.5\~10.2$ mm in total length with 11 (abdominal) +40 (caudal) = 51 myomeres. 24 days after hatching, the larva attained 19.4 mm in total length, at this time the larvae absorbed the yolk completely, and become postlarvae. 32 days after hatching, the larva attained 23.4 mm in total length, and become juvenile. 56 days after hatching, the juvenile reached 29.9 mm in total length and had adult form. 5 spines of preopercle bone were formed at 24.4 mm in total length. At ca. 15 mm in total length, the form of the pectoral fin was transformed into the adult form.

• Journal of the Korean earth science society
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• v.27 no.1
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• pp.95-117
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• 2006

From the Tertiary Yeonil Group distributed in Songra and Cheongha areas, the northern part of the Pohang Basin, nine archaeomonad species belonging to two genera, and other three types of chryophycean cysts considered as stomatocysts, five endoskeletal dinoflagellate species belonging to three genera and eighteen ebridian species belonging to eleven genera were identified. Based on above siliceous microfossil assemblages, the Yeonil Group is corresponded to Middle Miocene age. The group is correlated with the Calvert Formation (Maryland in USA) and the Hojuji Formation (in Central Japan) by its archaeomonad cysts. And, the group is correlated with the intervals of Actiniscus elongatus to Middle Hermesinella conata zones in Southwest Pacific region and of Spongebria miocenica to Middle Hermesineila schulzii zones in $V{\o}ring$ Plateau, Norwegian Sea, based on the ebridian assemblages of the group. From the chrysophycean cyst including archaeomonad, endoskeletal dinoflagellate and ebridian assemblages in the Yeonil Group of the study area, it is inferred that cold water masses dominated during the deposition oi the group with occasional warm water. The upper part of the group might be somewhat colder than the lower one of the group in depositional condition. In addition, minute chrysopycean cysts considered as stomatocysts suggest the influence of fresh or brackish water during the deposition of the group.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.135-143
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• 2014

This study classified abnormal sea surface temperature changes of the central pacific region according to three evolution patterns. Focusing on typhoons that affect the Korean Peninsula, the research analyzed typhoon's occurrence spot and track, change in the central pressure characteristics, and the characteristics of change in typhoon precipitation and the number of occurrences of heavy rainfall in the Nakdong River Basin. As a result of analysis, in case of prolonged-decaying years and symmetric-decaying years, typhoon-related summer rainfall and heavy rainy days appeared to be higher than long-term average. But in case of abrupt-decaying years, the pattern of general decrease appeared. This is because typhoon's occurrence spot is located comparatively near the Korean peninsula, typhoon's central pressure is high, and typhoon's route generally moves to Japan. As the outcome, this study is expected to reduce flood damage through analyzing the characteristics of typhoon's activity according to CP El Ni$\tilde{n}$o evolution patterns and the characteristics of local typhoon rainfall. In addition, it is expected to provide useful information for establishing adaptation and mitigation to climate change.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.151-159
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• 1993

Greeling, Hexagrammos otakii Jordan et Starks is commonly found at the coastal waters of Korea and Japan. The authors carried out the artificial insemination in the laboratory on Dec, 17, 1987, and reared the hatched larvae in an aquarium. The eggs were demersal and adhesive, and their diameters were 2.00~2.15mm. Color of yolk was light yellow in the early stage, and then turned to orange before hatching. The yolk had numerous tiny oil globules. Hatching began about 477hours after insemination under water temperature of $10.0{\sim}14.5^{\circ}C$. The newly hatched larvae were elongate in shape and 7.48~8.25mm in total length(TL) with 49~50 myomeres. The larvae absorbed the yolk material and oil globules completely in 5days after hatching and became postlarvae. In 17days after hatching, mean total length of the larvae was 9.85mm, and the caudal notochord flex at $45^{\circ}$. In 23days, total length reached 10.54mm. The part of the fin-fold of the future dorsal and anal fins became high. Spawning season of the Greenling is known to be from November to January in the southern coast of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.617-623
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• 2001

To predict the seasonal variation of dissolved oxygen (DO) in Hakata bay, Japan, possible 20 time-series of different hourly-solar-radiation intensities were generated based on stochastically changing solar radiation intensity, and a numerical simulation on dissolved oxygen (DO) was carried out for each time series by using the Sediment-Water Ecological Model (SWEM). The model, consisting of two sub-models with hydrodynamic and biological models, simulates the circulation process of nutrient between water column and sediment, such as nutrient regeneration from sediments as well as ecological structures on the growth of phytoplankton and zooplankton, The results of the model calibration followed the seasonal variation of observed water quality well, and generated cumulative-frequency-distribution (CFD) curves of daily solar radiation agreed well with observed ones, The simulation results indicated that the exchange of sea water would have a great influence on the DO concentration, and that the concentration could change more than 1 mg/L in a day. This prediction method seems to be an effective way to examine a solution to minimize fishery damage when DO is depleted.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.181-191
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• 2016

We estimate the eruption history and magmatic eruptive volumes of each rock units to evaluate the volcanic eruption scale and volcanic hazard of the Ulleung Island. Especially, Maljandeung Tuff represents about 19~5.6 ka B.P. from $^{14}C$ dating, and Albong Trachyandesite, about 0.005 Ma from K-Ar dating in recent age dating data. These ages reveal evidences of volcanic activities within the last 10,000 years, indicating that the Ulleung Island can classify as an active volcano with possibility of volcanic eruption near future. Accumulated DRE-corrected eruptive volume is calculated at $40.80km^3$, within only the island. The calculated volumes of each units are $3.71km^3$ in Sataegam Tuff, and $0.10km^3$ in Maljandeung Tuff but $12.39km^3$ in accounting the distal and medial part extended into southwestern Japan. Volcanic explosivity indices range 1 to 6, estimating from the volumes of each pyroclastic deposits. The colossal explosivity indices are 5 in Sataegam Tuff, and 6 in Maljandeung Tuff in accounting the distal and medial part. Therefore, it is necessary for appropriate researches regarding possibility of volcanic eruption of the island, and establishment system of the evaluation and preparation for volcanic hazard based on the researches is required.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.49-60
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• 2024

Recently, the frequency and intensity of typhoon-induced wave loading are increasing due to changed marine environments such as climate change. In addition, frequent earthquakes are causing a lot of damage around the world, including in Japan, Chile, Haiti, China, and Indonesia. In Korea, damage from typhoons has also been increasing since the 2000s, and the frequency and intensity of earthquakes are also increasing. Korea is surrounded by sea on three sides, so typhoons can cause a lot of damage to coastal structures, and earthquakes also cause a lot of damage to coastal structures. As such, the frequency and intensity of typhoon-induced wave loading and earthquakes are increasing both domestically and internationally, but there is no research linking typhoons and earthquakes. Therefore, in this study, numerical analysis was performed for a total of four cases by linking typhoon waves and earthquakes to the caisson breakwater. Numerical analysis was performed by applying wave loads in Case 1 and seismic wave in Case 2, seismic wave after wave loads in Case 3, and wave loads after seismic wave in Case 4. As a result of the numerical analysis, it was confirmed that in Case 3 and Case 4, which linked a typhoon and earthquakes, the damage caused by each load increased compared to Case 1 and Case 2 because the load was applied while the existing ground strength was reduced. In addition, it was confirmed that the greatest damage occurred in Case 3, in which seismic wave were applied after the wave loads.

• Journal of the Korean earth science society
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• v.21 no.3
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• pp.258-275
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• 2000

The purpose of this study is to investigate diurnal variations of snowstorm occurred along the East Coast of the Korean Peninsula. The snowstorm which occurred on 5${\sim}$7 January 1997 have been analyzed. The pressure patterns were analyzed through surface and upper-air chart(850hPa). Diurnal variations of four areas, i. e. Youngdong, Mt. Taebaek, Youngseo and Kyungbuk regions were analyzed through wind direction and speed, cloud amounts, surface temperature, dewpoint temperature, relative humidity and sea level pressure. And snowfall amounts over four areas were analyzed through regional distribution, daily and temporal variations. The snowfall which occurred on January 5 was caused by the weak low pressure which is located in Kyusu region of Japan. The snowfall of January 6 occurred due to the Siberian high's expansion and instability. And northeasterly wind is one factor of the snowstorm which occurred in Mt. Taebaek region on 7 January. Heavy snowfall was caused by westerly wind but easterly wind occurred weak snowfall in Youngdong area. The precipitation of Kyungbuk region(eapecially, Pohang) was less than that of Youngdong region because the air mass which was not modified had influence on Kyungbuk region on 6${\sim}$7 January, 1997.