• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.128-134
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• 2018

With the increase in frequency of typhoons and heavy rains following the climate change, the scale of damage from the calamities in the mountainous areas has been growing larger and larger, which is different from the past. For the case of Korea where 64% of land is consisted of the mountainous areas, establishment of the check dams has been drastically increased after 2000 in order to reduce the damages from the debris flow. However, due to the lack of data on scale, location and kind of check dams established for reducing the damages in debris flow, the measures to prevent damages based on experience and subjective basis have to be relied on. Under this study, the high-precision DEM data was structured by using the terrestrial LiDAR in the Jecheon area where the debris flow damage occurred in July 2009. And, from the numerical models of the debris flow, Kanako-2D that is available to reflect the erosion and deposition action was applied to install the erosion control facilities (water channel, check dam) and analyzed the effect of reducing the debris flow shown in the downstream.After installing the erosion control facilities, most of debris flow moves along the water channel to reduce the area to expand the debris flow, and after installing the check dam, the flow depth and flux of the debris flow were reduced along with the erosion. However, as a result of analyzing the diffusion area, flow depth, erosion and deposition volume of the debris flow generated from the deposition part after modifying the location of the check dams with the damages occurring on private residences and agricultural land located on the upstream area, the highest reduction effect was shown when the check dam is installed in the maximal discharge points.

• Ocean and Polar Research
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• v.34 no.2
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• pp.197-199
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• 2012

According to the IPCC climate change scenario (A1B scenario), the surface seawater temperature of the South Sea of Korea by 2100 may be $2-3.5^{\circ}C$ higher than at present, and seawater pH may decrease from 8.1 to 7.8, due to the increase in atmospheric $CO_2$, which is predicted to increase in concentration from 380 to 750 ppm. These changes may not only intensify the strength of typhoons/storm surges but also affect the function and structure the marine ecosystem. In order to assess the impact of climate change on the marine ecosystem in Korean waters, the project named the 'Assessment of the impact of climate change on marine ecosystem in the South Sea of Korea' has been supported by the Ministry of Land, Transport and Maritime Affairs, from 2008. The goal of this project is to enhance our ability to adapt and prepare for the future environmental changes through the reliable predictions based on the knowledge obtained from projects like this. In this respect, this project is being conducted to investigate the effects of climate/marine environment changes (ocean warming and acidification), and to predict future changes of the structure and function of the ecosystem in the South Sea of Korea. This special issue contains 6 research articles, which are the highlights of the studies carried out through this project.

• Ocean and Polar Research
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• v.31 no.4
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• pp.369-377
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• 2009

Performance of the Korea Ocean Research and Development Institute (KORDI) operational storm surge prediction system for the Korean coast is presented here. Results for storm surge hindcasts and forecasts calculations were analyzed. The KORDI storm surge system consists of two important components. The first component is atmospheric models, based on US Army Corps of Engineers (CE) wind model and the Weather Research and Forecasting (WRF) model, and the second components is the KORDI-storm surge model (KORDI-S). The atmospheric inputs are calculated by the CE wind model for typhoon period and by the WRF model for non-typhoon period. The KORDI-S calculates the storm surges using the atmospheric inputs and has 3-step nesting grids with the smallest horizontal resolution of ${\sim}$300 m. The system runs twice daily for a 72-hour storm surge prediction. It successfully reproduced storm surge signals around the Korean Peninsula for a selection of four major typhoons, which recorded the maximum storm surge heights ranging from 104 to 212 cm. The operational capability of this system was tested for forecasts of Typhoon Nari in 2007 and a low-pressure event on August 27, 2009. This system responded correctly to the given typhoon information for Typhoon Nari. In particular, for the low-pressure event the system warned of storm surge occurrence approximately 68 hours ahead.

• Ocean and Polar Research
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• v.36 no.2
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• pp.165-177
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• 2014

In an effort to investigate the structure and variability of the coastal current in the East Sea, a moored ADCP observation was conducted off Uljin from late May to mid-October 2006. Owing to the transition of season from summer to autumn, the features of the current and wind can be divided into two parts. Until mid-August (Part-I), a southward flow is dominant at all depths with a mean alongshore velocity of 4.2~8.9 cm/s but northward winds are not strong enough to reverse the near-surface current. During Part-II, a strong northward current occurs frequently in the upper layer but winds are predominantly southward including two typhoons that have deep-reaching influence. Profile of mean velocity has three layers with a northward velocity embedded at 12~28 m depth. The near-surface current of Part-II significantly coheres with winds at 4-8 day periods with a phase lag of about 12 hours. The modal structure of the current obtained by EOF analysis is: (1) Mode-1, having 83.6% of total variance, represents the current in the same direction at all depths corresponding to the southward North Korean Cold Current (NKCC). (2) Mode-2 (11.7%) reveals a two-layer structure that can be explained by the northward East Korean Warm Current (EKWC) in the upper layer and NKCC in the lower. (3) Mode-3 (2.6%) has three layers, in which the EKWC is reversed near the surface by opposing winds. This mode is particularly similar to the mean velocity profile of Part-II.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.498-504
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• 2013

Recently, the frequency of typhoons have increased due to the effects of climate change. As a result, in mountain streams, it has caused streamflow increase upstream and frequent water surface elevation downstream. This study analyzed the effects of the heavy rainfalls caused by Typhoon Sanba, which had a direct impact on Korea between September 17 and 18, on the water level variations downstream in mountainous streams. In addition, the drainage basin of Samcheok Oship stream was chosen as the object of this study. This study analyzed the flood level by applying HEC-RAS model. The observed water level measured in 2012 and the water level simulated by HEC-RAS model showed similar results. In addition, the simulation results showed the maximum flood level was 5.32m the mean flow velocity was 2.33m/sec and the maximum channel water depth was 7.51m. The analysis showed that the heavy rainfalls caused by Typhoon Sanba had an impact on the water surface elevation in Oship stream. The final results from this study will give a reasonable and important data to perform the Design of Hydraulic Structure.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.74-79
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• 2017

The Geostationary Ocean Color Imager (GOCI), the world's first ocean color sensor operated in a geostationary orbit, can be utilized to mitigate damages by monitoring marine disasters in real time such as red tides, green algae, sargassum, cold pools, typhoons, and so on. In this paper, we described a methodology and procedure for processing GOCI data in order to maximize its utilization potential. The GOCI data processing procedure is divided into data reception, data processing, and data distribution. The kinds of GOCI data are classified as raw, level 1, and level 2. "Raw" refers to an unstructured data type immediately generated after reception by satellite communications. Level 1 is defined as a radiance data type of two dimensions, generated after radiometric and geometric corrections for raw data. Level 2 indicates an ocean color data type from level-1 data using ocean color algorithms.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.453-458
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• 2010

This paper studies relationship between global warming and trends of typhoon variation by using the meteorological long-term data. The results show that yearly mean typhoon's occurrence numbers decrease and maximum wind speeds strengthen gradually. These results are in accord with most of simulated results. While the normal course of typhoon is increased, the westward course of that is decreased. Typhoon trajectories show that the ratios of normal course 6 : westward course 3 : abnormal course 1 in the last 10 years. Among typhoons which affect to the Korea ones pass through the southern coast of Korea are the most. The numbers of typhoon pass through the western coast of Korea are decreased and those pass through the eastern coast of Korea show increasing trend lately. The notable point in relation to the global warming is that typhoon intensity is strengthened gradually. Watch and counterplan in the viewpoint of prevention to the meteorological disasters are required.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.437-445
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• 2016

Since typhoon is a critical meteorological disaster, some advanced countries have developed typhoon damage prediction models. However, although South Korea is vulnerable to typhoons, there is still shortage of study in typhoon damage prediction model reflecting the vulnerability of domestic building and features of disaster. Moreover, many studies have been only focused on the characteristics and typhoon and regional characteristics without various influencing factors. Therefore, the objective of this study is to analyze typhoon damage by path and develop to prediction model for building damage ratio by using multiple regression analysis. This study classifies the building damages by typhoon paths to identify influencing factors then the correlation analysis is conducted between building damage ratio and their factors. In addition, a multiple regression analysis is applied to develop a typhoon damage prediction model. Four categories; typhoon information, geography, construction environment, and socio-economy, are used as the independent variables. The results of this study will be used as fundamental material for the typhoon damage prediction model development of South Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.210-216
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• 2012

EST has been applied to the East Coast to estimate extreme sea levels. Surge heights induced by 51 typhoons which have occurred last 60 years were calculated by ADCIRC model. The training set which is consist of surge heights by both typhoon and monsoon was constructed. The maximum surge height of the year excluding the one by typhoon is considered to be the surge height by monsoon. High/low tide conditions and spring/neap tide conditions were considered for constructing input vectors of typhoon and monsoon, respectively. The annual tide is also considered in response vectors for each case. The result is in accord with Jeong et al. (2008), which implies validity of the present study.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.91-101
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• 2010

As global warming has caused the number of abnormal changes in climate to increase throughout the world, much damage has occurred recently in Korean Peninsula which results from unexpected heavy rains, landslides, and floods from typhoons. To prevent and cope with these annually repeated natural hazards, the overall improvements are needed, including systematic management of the existing natural hazard information and improvement of hazard information. In this study, multi-purpose hazard information map based on digital image was constructed as an effective way to enhance hazard management considering regional characteristics and hazard response capabilities in the field. Multi-purpose hazard information map with a new concept by fusion of geospatial information and hazard attribute information is able to support quick decision for hazard management making and development of hazard information system.