• Environmental and Resource Economics Review
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• v.31 no.3
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• pp.343-365
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• 2022

This paper tries to identify the effect of reducing PM2.5 concentration of the First Seasonal Management Policy implemented by Korean government by using statistical method. In particular, this paper tests the hypothesis that this policy effect may differ by region (west-coast, south-coast, and east-coast). To this end, this paper analyzed only pure policy effects by removing temporal abnormalities such as COVID-19, warm winter temperature during the policy implementation period (December 2019 to March 2020) by using the difference-in-difference method (DID). As a result of the analysis, this policy had the effect of reducing PM2.5, but the effect is not homogenous by region. In particular, PM2.5 reducing effect is the largest in west-coast region and south-coast region folllows, but its effect is not statistically significant in the east-cost region. In conclusion, this paper drew implications that the current Seasonal mamangement policy which is implemented regardless of the regional difference needs to be changed.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.607-614
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• 2019

It has been an issue among researchers that the tsunamis that occurred on the west coast of Japan in 1983 and 1993 damaged the coastal cities on the east coast of Korea. In order to predict and reduce the damage to the Korean Peninsula effectively, it is necessary to install offshore tsunami observation instruments as part of the system for the early detection of tsunamis. The purpose of this study is to recommend the optimal deployment of tsunami observation instruments in terms of the higher probability of tsunami detection with the minimum equipment and the maximum evacuation and warning time according to the current situation in Korea. In order to propose the optimal location of the tsunami observation equipment, this study will analyze the tsunami propagation phenomena on the east sea by considering the potential tsunami scenario on the west coast of Japan through numerical modeling using the COrnell Multi-grid COupled Tsunami (COMCOT) model. Based on the results of the numerical model, this study suggested the optimal deployment of Korea's offshore tsunami observation instruments on the northeast side of Ulleung Island.

• Journal of Navigation and Port Research
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• v.35 no.9
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• pp.755-763
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• 2011

Recently, extreme tsunami waves generated by submarine earthquake have caused tremendous damages to the coastal cities and ports. Strong seiche oscillations and runups are observed in specific sea areas around the world. Although no frequent impacts to the coast of Korean peninsula, there exist some important events in the east of Korea in the past. This study focuses on two historical events and recalculate with different fault and rupture mechanism for prediction considering the recent trend of submarine earthquake. The present study of the 1983 Akita tsunamis demonstrates the multi-scale resonance along continental coasts. Together with the Nankai tsunami for inland sea, we have confirmed the inland sea resonance surrounded by islands in defining the impact along the coast. Coherence and wavelet analyses for deducing a predominant period and time frequency are useful in reasoning the inundation. The resonance modes, which are largely independent of the tsunami source, allow identification of at-risk communities and infrastructure for mitigation of tsunami hazards. Furthermore, understanding of the resonance and the predicted runups for the site of power plant and industrial complex in the east coast of Korea would allow better preparation for the future disasters.

• Journal of The Geomorphological Association of Korea
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• v.27 no.1
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• pp.21-31
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• 2020

Planting pine trees on the coastal dunes has been carried out along the East coast as well as West coast of South Korea. Although the artificial forestation has been regarded as a good policy that help to protect the coastal area from natural disasters, but its real effect to the landscapes is still unknown. In this study, we have installed a monitoring site with an automated weather station to study requirements for dune formation and its environmental changes in Osan beach, Yangyang-Gun, Gangwon Province. We analyzed the meteorological data collected from 2010 to 2019 and vegetational changes in the study area. As a result, the wind speed is decreased by around 30% and the pine-covered area is increased by around 300m² after planting Japanese Black Pine in 2015. At present, it seems that the eolian transport of sand particle is minimal, because the dominant winds are the westerly winds which is not landward but seaward, and because the surface roughness length is about 0.5m which is similar to that in the deciduous forest.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.299-304
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• 1983

A tongue-like warm water which is a part of the Tsushima Warm Current appears whole year around in the east entrance of the Jeju Strait. Because of this warm water, the current direction flowing into the Jeju Strait from its west area seems to be changed in the Jeju Strait. Therefore the intermediate and bottom water of the Jeju Strait may greatly influence the formation of the coastal water in the South Coast of Korea. Since this tongue-like warm water is stronger in winter than in summer in its formation, Tsushima Warm Current comes closer to the South Coast of Korea in winter and its north boundary frequently approaches close to the coast of Geomun Island and Sori Island.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.645-655
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• 2022

Recently rip currents are frequently observed in the summer at the beaches located along the East Sea coast. To understand the generation types of rip currents occurred at the Ease Sea beaches, numerical simulations of rip currents over the topographies of the Sokcho, Naksan, Gyeongpo, Mangsang beaches were performed by using a Boussinesq-type wave and current model, FUNWAVE. The offshore and nearshore topographically-controlled rip currents and the transient rip currents were well reproduced due to the alongshore non-uniformities involving the phase interaction effects. This study looked over the generation types of rip currents to occur at the beaches with complicated field bathymetries.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.65-75
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• 1973

Morphological variations of the Korean Oyster, Crassostrea gigas, were studied on the basis of the oyster samples collected from seven ecologically different areas in May and October of 1972 respectively. The sampling areas were Daecheon and Buan in the west coast, Namseong, Cha-myeon, Imyeong and Chubong in the south coast and Pohang in the east coast. The average sizes of the oysters of the west coast were smaller than those of the south coast as well as those of the east coast. The oysters of the east were largest in size, The oysters from subtidal habitats (Chubong and Pohang) had elongated shells and those from intertidal habitats (Buan, Namseong, Imyeong and Chamyeon) had slanted shells. The samples from subtidal habitats showed size variations depending on cultural methods applied. The oysters from Chubong reared by hanging method had their shells as compared to those from Pohang reared by bottom culture method. The ratio of shell height to shell length showed a great variation froms areas to areas with a significant differences. The fatness (meat weight / shell weight) of all the samples collected in October revealed higher value than those collected in May. The oysters from Chubong showed maximum fatness, and those of Pohang showed minimum fatness. Seasonal variations in fatness was not significant in Chubong. On the other hand, it was relatively significant in the oysters from Pohang, Chamyeon, Imyeong and Buan. Water content of the oyster meat was greater in October than in May. It also showed variations in the sampling areas with higher values in the oyster from Imyeong and Chamyeon than those from Chubong, Pohang and Daecheon.

• 한국해양학회지
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• v.20 no.2
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• pp.22-27
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• 1985

To examine the summertime coastal current along the cast coast of Korea, we carried out hydrographic and current measurements in the coastal area of Chumunjin during July-August, 1982. Hydrographic results showed that isotherms, isohalines and isopycnals had a downward slope toward the coast in a layer of 0∼100m and that there existed relatively large horizontal gradients across shelf of salinity and density, mainly due to heavy precipitation in summer. It was found that there existed a strong southward flow along the coast reaching its maximal speed of about 70cm/sec in the nearshore area and that shear and speed of the observed current were coincident with orders of geostrophic current.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.451-454
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• 2008

Potential tsunamis which may occur near Ryukyu Islands were simulated. Propagation characteristics of the potential tsunamis over the southwestern sea and the influence of tsunamis on the southwestern coast of Korean Peninsula were analyzed. The shallow water area in the east sea of China and the deep water Okinawa Trough play an important role in wave transformation and propagation of the potential tsunamis. The propagation characteristics of the potential tsunamis generated near Ryukyu Islands can be described as in followings : In the first stage after generation, the tsunamis propagate with high speed both northeastward and southwestward along the Okinawa Trough. As a result the waves are elongated and the tsunami height is significantly reduced. The elongated crest of tsunamis spans the whole distance of the Okinawa Trough and lines up toward the edge of the continental shelf of East China Sea. Then, the tsunamis are propagating towards the southeast coast of China. Thus, the influence of tsunamis on the Korean coasts becomes weak.

• Water for future
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• v.7 no.2
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• pp.99-106
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• 1974

The records of wave heights which were observed at Muk ho and Po hang of the East Coast of Korea were analized by several probility functions. The exponential 2 parameter distribution was found as the best fit probability function to the historical distribution of wave heights by the test of goodness of fit. But log-normal 2 parameter and log-extremal type A distributions were also fit to the historical distribution, especially in the Smirnov-Kolmogorov test. Therefore, it can't be always regarded that those two distributions are not fit to the wave heiht's distribution. In the test of goodness of fit, the Chi-Square test gave very sensitive results and Smirnov-Kolmogorov test, which is a distribution free and non-parametric test, gave more inclusive results. At the next stage, the inter-relationship between the mean and the one-third wave heights, the mean and the one-=tenth wave heights, the one-third and the one-tenth wave heights, the one-third and the highest wave heights were obtained and discussed.