• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.227-234
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• 2004

Recently huge typhoons had attacked to the coastal waters in Korea and caused disastrous casualties in those area. There are some discussions on correction to the design parameters for the coastal structures. Wave transformation computations with the extreme waves are of value in planning and constructing engineering works, especially in coastal regions. Prediction of typhoon surge elevations is based primarily on the use of a numerical model in this study, since it is difficult to study these events in real time or with use of physical models. Wave prediction with a two dimensional numerical model for a site with complicated coastal lines and structures at the period of typhoon 'Maemi' is discussed. In order to input parameters for the extreme wave conditions, we analyzed the observed and predicted typhoon data. Finally we applied the model discussed above to the storm surge and extreme wave problem at Busan Harbor, the southeast coast of Korea. Effects of water level variation and transformation of the extreme waves in relation with the flooding in coastal waters interested are analyzed. We then mack an attempt to presen a basic hazard map for the corresponding site.

• Spatial Information Research
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• v.17 no.3
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• pp.341-350
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• 2009

As the power and scale of typhoons are growing due to global warming and socioeconomic damages induced by super-typhoons are increasing, it is important to estimate inundation damages and to prepare proper adaptation plans against an attack of the super-typhoon. In this paper, we estimated the inundation damages of urban area around Haeundae beach induced by super-typhoons which follow the route of Typhoon Maemi with the conditions of Typhoon Vera (Ise Bay in Japan, 1959), Typhoon Durian (Philippine, 2006) and Hurricane Katrina (New Oleans in U.S.A, 2005). The coastal area around the Haeundae beach (Busan and Gyeongnam province) is expectedly damaged by severe storm surges. In this study we calculated the rise of sea level height after harmonizing the different datum levels of land and ocean and estimated the inundation depth, inundation area and the amount of building damages by using airborne LiDAR data and GIS spatial analysis techniques more accurately and quantitatively. As many researchers are predicting that super-typhoon of overwhelming power will occur around the Korean peninsula in the near future, the results of this study are expected to contribute to producing coastal inundation map and evacuation planning.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.5
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• pp.253-264
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• 2019

Storm surges caused by a typhoon occur during the summer season, when the sea-level is higher than the annual average due to steric effect. In this study, we analyzed the sea-level pressure and tidal data collected in 1 h intervals at Incheon, Kunsan, Mokpo, Seogwipo stations on the Yellow Sea coast to analyze the summer season storm surge and wave overtopping. According to our analyses, the summer mean sea-level rise on the west and south coasts is approximately 20 cm and 15 to 20 cm higher than the annual mean sea-level rise. Changes in sea-level rise are closely related to changes in seasonal sea-level pressure, within the range of 1.58 to 1.73 cm/hPa. These correlated mechanisms generates a phase difference of one month or more. The 18.6 year long period tidal constituents indicate that in 2090, the amplitude of the $M_2$ basin peaks on the southwest coast. Therefore, there is a need to analyze the target year for global warming and sea-level rise in 2090. Wave overtopping was simulated considering annual mean sea-level rise, summer sea level rise, the combined effect of nodal factor variation, and 100-year frequency storm surge. As a result, flooding by wave overtopping occurs in the area of Suyong Bay, Busan. In 2090, overtopping discharges are more than doubled than those in Marine City by the recent typhoon Chaba. Adequate coastal design is needed to prepare for flood vulnerability.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.13-24
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• 2019

The concept of shape similarity has been applied to verify the accuracy of the SIND model, the real-time prediction model for disaster risk. However, the CRITIC method, one of the most widely used in geometric methodology, is definitely limited to apply to complex shape such as hazard map for coastal disaster. Therefore, we suggested the modified CRITIC method of which we added the shape factors such as RCCI and TF to consider complicated shapes. The matching pairs were manually divided into exact-matching pairs and mis-matching pairs to evaluate the applicability of the new method for shape similarity into hazard maps for storm surges. And the shape similarity of each matching pair was calculated by changing the weights of each shape factor and criteria. Newly proposed methodology and the calculated weights were applied to the objects of the existent hazard map and the results from SIND model. About 90% of exact-matching pairs had the shape similarity of 0.5 or higher, and about 70% of mis-matching pairs were it below 0.5. As future works, if we would calibrate narrowly and adjust carefully multi-objects corresponding to one object, it would be expected that the shape similarity of the exact-matching pairs will increase overall while it of the mis-matching pairs will decrease.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.506-513
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• 2020

Due to climate change, there is an increasing risk of complex (hybrid) disasters, comprising rising sea-levels, typhoons, and torrential rains. This study focuses on Marine City, Busan, a new residential city built on a former landfill site in Suyeong Bay, which recently suffered massive flood damage following a combination of typhoons, storm surges, and wave overtopping and run-up. Preparations for similar complex disasters in future will depend on risk impact assessment and prioritization to establish appropriate countermeasures. A framework was first developed for this study, followed by the collection of data on flood prediction and socioeconomic risk factors. Five socioeconomic risk factors were identified: (1) population density, (2) basement accommodation, (3) building density and design, (4) design of sidewalks, and (5) design of roads. For each factor, absolute criteria were determined with which to assess their level of risk, while expert surveys were consulted to weight each factor. The results were classified into four levels and the risk level was calculated according to the sea-level rise predictions for the year 2100 and a 100-year return period for storm surge and rainfall: Attention 43 %, Caution 24 %, Alert 21 %, and Danger 11 %. Finally, each level, indicated by a different color, was depicted on a complex disaster risk map.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.71-82
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• 2012

This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.770-778
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• 2023

Sea surface wind is an important variable for elucidating the atmospheric-ocean interactions and predicting the dangerous weather conditions caused by oceans. Accurate sea surface wind data are required for making correct predictions; however, there are limited observational datasets for oceans. Therefore, this study aimed to obtain long-period high-resolution sea surface wind data. First, the ERA5 reanalysis wind field, which can be used for a long period at a high resolution, was regridded and synthesized using the asymmetric typhoon wind field calculated via the Generalized Asymmetric Holland Model of the numerical model named ADvanced CIRCulation model. The accuracy of the asymmetric typhoon synthesized wind field was evaluated using data obtained from Korea Meteorological Administration and Japan Meteorological Administration. As a result of the evaluation, it was found that the asymmetric typhoon synthetic wind field reproduce observations relatively well, compared with ERA5 reanalysis wind field and symmetric typhoon synthetic wind field calculated by the Holland model. The sea surface wind data produced in this study are expected to be useful for obtaining storm surge data and conducting frequency analysis of storm surges and sea surface winds in the future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.79-90
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• 2009

This paper presents the development of dynamically combined Typhoon generated surge-tide-wave numerical model which is applicable from deep to shallow water. The dynamically coupled model consists of hydrodynamic module and wind wave module. The hydrodynamic module is modified from POM and wind wave module is modified from WAM to be applicable from deep to shallow water. Hydrodynamic module computes tidal currents, sea surface elevations and storm surges and provide these information to wind wave module. Wind wave mudule computes wind waves and provides computed information such as radiation stress, sea surface roughness and shear stress due to winds. The newly developed model was applied to compute the surge, tide and wave fields by typhoon Maemi. Verification of model performance was made by comparison of measured waves and tide data with simulated results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.67-73
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• 2012

Coastal erosion and its impact on human activities as well as the economic damage and environmental conservation of coastal area is one of major concern in the national policies. In this study, we conducted physical investigations to evaluate effects of erosion in the Geojin beach, which is located nearby the Geojin Port, for a detecting of shoreline change and beach cross-sectional area. The results showed that significant coastal erosion of the Geojin beach has occurred by the complex resources of natural factor, such as rising sea level, storm surges, high wave, and man-made construction. Especially, due to the sand supplement from Jasan river, the section which is nearby the estuary of Jasan river is maintained as a stable beach, whereas beach erosion of the other site in GW04 section has been increased indeed. Therefore, we suggest that it is need to continuous monitoring using DGPS and various surveying techniques to prevent beach erosion onto the GW04 section.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.84-93
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• 2016

As a transition region between ocean and land, coastal wetlands are significant ecosystems that maintain water quality, provide natural habitat for a variety of species, and slow down erosion. The energy of coastal waves and storm surges are reduced by vegetation cover, which also helps to maintain wetlands through increased sediment deposition. Wave attenuation by vegetation is a highly dynamic process and its quantification is important for understanding shore protection and modeling coastal hydrodynamics. In this study, laboratory experiments were used to quantify wave attenuation as a function of vegetation type as well as wave conditions. Wave attenuation characteristics were investigated under regular waves for rigid model vegetation. Laboratory hydraulic test and numerical analysis were conducted to investigate regular wave attenuation through emergent vegetation with wave steepness ak and relative water depth kh. The normalized wave attenuation was analyzed to the decay equation of Dalrymple et al.(1984) to determine the vegetation transmission coefficients, damping factor and drag coefficients. It was found that drag coefficient was better correlated to Keulegan-Carpenter number than Reynolds number and that the damping increased as wave steepness increased.