• Atmosphere
• /
• v.32 no.3
• /
• pp.207-221
• /
• 2022

In Jeju, on January 23, 2016, a cold surge accompanied by heavy snowfall with the most significant amount of 12 cm was the highest record in 32 years. During this period, the temperature of 850 hPa in January was the lowest in 2016. Notably, in 2016, the average surface temperature of January on the Polar cap was the highest since 1991, and 500 hPa geopotential height also showed the highest value. With this condition, the polar vortex in the northern hemisphere meandered and expanded into the subtropics regionally, covering the Korean Peninsula with very high potential vorticity up to 7 Potential Vorticity Unit. As a result, the strong cold advection, mostly driven by a northerly wind, around the Korean Peninsula occurred at over 2𝜎. Previous studies have not addressed this extreme synoptic condition linked to polar vortex expansion due to the unprecedented Arctic warming. We suggest that the occurrence of a strong Ural blocking event after the abrupt warming of the Barents/Karas seas is a major cause of unusually strong cold advection. With a specified mesoscale model simulation with SST (Sea Surface Temperature), we also show that the warmer SST condition near the Korean Peninsula contributed to the heavy snowfall event on Jeju Island.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.19 no.5
• /
• pp.492-501
• /
• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.

• Journal of KIBIM
• /
• v.13 no.2
• /
• pp.1-15
• /
• 2023

Since the 1960s, the Korean Peninsula, which consists of 77.4 of the country's land and mountains, has seen a surge in demand for buildings due to population concentration due to urbanization and industrialization. Since then, the development of slopes has been inevitable due to the concentration and expansion of the city's population. When building a building on a slope, it is important to set the height of the surface. In this case, the means of regulating buildings in construction-related laws, such as the building closure ratio, floor area ratio, number of floors and total floor area of buildings, have an overall effect on buildings through the height of the surface. In the Korean Building Act, the setting of the height of the ground affects the calculation of the building height limit standard and the calculation of the underground floor, and it takes a long time to calculate. Therefore, the time required for attempts to change various design plans of buildings increases. The purpose of this study is to speed up the time required to calculate the weighted average of the surface when constructing buildings on slopes. In addition, the existing calculation process allows various design attempts compared to the same time given.

• Ocean Systems Engineering
• /
• v.3 no.3
• /
• pp.181-201
• /
• 2013

The main objective of this work is to investigate the sloshing behavior in a baffled and unbaffled three dimensional annular-sectored water pool (i.e., tank) which is located at dome region of the primary containment. Initially two case studies were performed for validation. In these case studies, the theoretical and experimental results were compared with numerical results and good agreement was found. After the validation of present numerical procedure, an annular-sectored water pool has been taken for numerical investigation. One sector is taken for analysis from the eight sectored water pool. The free surface is captured by Volume of Fluid (VOF) technique and the fluid portion is solved by finite volume method while the structure portions are solved by finite element approach. Baffled and un-baffled cases were compared to show the reduction in wave height under excitation. The complex mechanical interaction between the fluid and pool wall deformation is simulated using a partitioned strong fluid-structure coupling.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.4
• /
• pp.595-602
• /
• 2009

In this study, a two-dimensional storm surges/tide prediction model called the Storm surges/Tide Operational Model (STORM) was applied as the operational forecast model of the Korea Meteorological Administration (KMA). The operational model results were verified for two years (2006-2007) using observed results from tidal stations. Comparisons of modeled and observed storm surges show that larger differences at the western coast of Korea than at the southern and eastern coasts. The averaged root mean square error between the modeled and observed storm surges height are 0.16 m and 0.10 m in 2006 and 2007, respectively.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2015.11a
• /
• pp.278-279
• /
• 2015

최근 해수욕장, 저지대 침식, 해안시설물 노후화 등과 같이 해안지역 구성 및 지형적 요인에 따라 국지적으로 발생하는 피해와 태풍 및 이상너울 등의 대규모 기상현상에 의해 해안재난이 발생가능성이 높아지고 실제 발생하는 실정이다. 본 논문에서는 재난대응을 위한 과학적 재난정보 수집 및 분석을 통해 의사결정에 활용하고 효과적으로 예방 대응하고자 유관기관에서 다양하게 구축된 시스템의 재난관련 자료를 수집하였으며, 태풍 내습시 신속한 대응을 위해 폭풍해일 시뮬레이션을 통해 범람파고를 추정하였다. 기존 상황판단을 위한 정보수집단계에 추가적으로 관측자료 및 시뮬레이션을 통한 정량적 피해추정정보를 신속하게 제공함으로서 재난상황판단을 가능할 수 있도록 방안을 마련하였다.

• Journal of Korean Society for Geospatial Information Science
• /
• v.15 no.4
• /
• pp.97-102
• /
• 2007

Recently, coastal damage according to the natural disaster like storm-surge, overflowing of the sea has been massively increased. In case of earth fill at the seaside, there are a lot of weak areas of the natural disaster and it has also high possibility that a large disaster happens. Thus flood expectation map in the reclaimed land using 3D spatial information was produced in this study. The area around Myungji, Kangsugu, Busan which was made with the large scale earth fils at the seaside was designated as a study area. Observation of both costal datum and ground height using the tidal date and field surveying dates was conducted. Terrain model using the GIS program was produced and than 3D building model was produced using 3D MAX. It was shown that there are possibility more than 50% if over 4.5m storm-surge is happening, as a result of calculating the virtual flooded area on the produced cartographic map.

• Journal of the Korean earth science society
• /
• v.25 no.4
• /
• pp.277-288
• /
• 2004

In this study, state of sea surface were analyzed comparatively for cases of low atmospheric pressure, which occurred in the middle area of China and moved eastward to the Korean Peninsula across the Yellow sea during April 9-12, 1999, and typhoons 'NEIL' May 1999 and 'OLGA' July 1999, which moved northward along the west coast of the Korean Peninsula. In cases of low pressure, wind speeds and phases were respectively stronger and faster in the center area than in the surrounding areas. The wave heights seem to a somewhat differing tendency from that of the wind speeds due to the influences of geometry. On the other hand, wave heights were lower under typhoon weather than under low pressures, except the instance of wave height over 5 m on Chilbal when typhoon Olga pass northward from the southern area. Storm surges also showed larger amplitudes under low pressures than under typhoons. The results suggest that wave sand storm surges may be larger for a slow passing synoptic low pressures than for a fast passing local typhoon.

• Atmosphere
• /
• v.25 no.3
• /
• pp.435-447
• /
• 2015

This study explores the synoptic characteristics of cold days over South Korea and their relationship with large-scale climate variability. The cold day, which is different from cold surge, is defined when daily-mean surface air temperature, averaged over 11 KMA stations, is colder than 1-percentile temperature in each year by considering its long-term trend over 1960~2012. Such event is detected by quantile regression and the related synoptic patterns are identified in reanalysis data. Composite geopotential height anomalies at 500 hPa show that cold days are often preceded by positive anomalies in high latitudes and negative anomalies in midlatitudes on the west of Korea. While the formers are quasi-stationary and quasi-barotropic, and often qualified as blocking highs, the latters are associated with transient cyclones. At cold days, the north-south dipole in geopotential height anomalies becomes west-east dipole in the lower troposphere as high-latitude anticyclone expands equatorward to the Northern China and mid-latitude cyclone moves eastward and rapidly develops over the East Sea. The resulting northerlies cause cold days in Korea. By performing composite analyses of large-scale climate indices, it is further found that the occurrence of these cold days are preferable when the Arctic Oscillation is in its negative phase and/or East Asian monsoon circulation and Siberian high are anomalously strong.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.124-124
• /
• 2023

본 연구에서는 태풍의 이동속도(TS), 상륙각도(LA) 및 연안 지형이 최대 해일고(MSH)에 미치는 복합적인 효과를 분석하기 위해, 이상적인 시나리오와 실제 규모의 사상에 대한 수치모의를 수행였으며. 이를 통해 태풍 진행시 연안을 따라 분포하는 최대 해일고의 일반적 특성을 도출하고자 한다. Delft3D-FM의 2차원 모델을 사용하여 수치모의를 진행하였으며, 모델 도메인은 태풍의 상륙 지점을 연안 중심에 위치시켜고 16km에서 1km까지 다중 해상도 격자로 구성하였다. 가상의 태풍은 다양한 TS와 LA 조건에 따라 생성되었고, TS는 기존의 태풍 사상들의 특성을 통계적으로 분석하여 유의한 범위에서 변화하도록 설정하는 반면, LA의 경우 0도에서 180도까지 15도 간격으로 변화시켰다. 또한, 연안형상과 해저 지형도 다양한 형태를 고려하였는데 해저 지형의 경우일정수심 혹은 여러 가지 대륙붕 폭을 지닌 지형, 다중 경사 지형 등이 고려되었다. 연안형상의 경우 형태 비율로 특징 지어지는 개방 연안과 만이 고려되었다. 총 763개의 이상적인 시나리오가 모의되었으며 그 결과 연안을 따라 MSH 분포를 분석하였다. 이상적인 시나리오에서 개발된 효과의 적용성을 검증하기 위해 다양한 TS와 LA 조건에서 역사적인 태풍 매미를 기반으로 현실적인 규모의 시나리오 모의가 실시되었다. 그 결과 빠르게 이동하는 TS가 개방 연안을 따라 분포하는MSH를 증폭시킨다는 사실을 재확인하는 등, 연안지형, 태풍의 특성에 따른 최대 푹풍해이고 변화에 대한 다양한 결과를 얻을 수 있었다.