마산시 해일방어 시설물 구축을 위한 설계 해일고 산정

강시환(Kang See Whan),전기천(Jun Ki Cheon),한성대(Han Sung Dae) 한국해양환경·에너지학회 2004 한국해양환경·에너지학회 학술대회논문집 Vol.2004 No.-

Typhoon 0314(Maemi) caused a severe storm surge on the southern coast of Korea, especially in Masan- Jinhae Bay. The tide gage in Masan Port recorded the maximum surge height of ~ 2.3m which is a record of the extreme surge height for the last 100 years since the opening of Masan port. In order to obtain the maximum surge height for the design of storm-surge defence structures on the Masan Coast, the storm surge caused by typhoon "Maemi" was hindcasted using a fine-scaled regional model. The hindcasted surge heights were compared with the observations. The result shows that they are in a good agreement with the observed storm-surge heights.

한반도 주변 해역에서의 MetOp-B와 Jason-2 인공위성 해상풍 검증

손동휘(Donghwi Son),전기천(Kicheon Jun),심재설(Jae-Seol Shim),권재일(Jae-il Kown),유제선(Jeseon Yoo) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.4

In the last few decades, many studies on estimation of sea surface winds using satellites have been increasingly carried out with advancement of remote sensing technology. In prior to the use of satellite data for physical analysis, validation and calibration of the satellite raw data should be conducted. Most of the previous validation studies have mainly focused on the offshore data which were collected 50km or more away from the coastline. This is to remove the effect of land interference from the radar signal data. In this study, a method of validating wind speed data based on wind direction is proposed to improve the validation, in particular, for the satellite data collected in coastal area, intending to enhance the utilization of the satellite data which is adjacent to the land. MetOp-B and Jason-2 data were considered as satellite dataset. For the validation of the satellite data, the in-situ measurements from Korea Meteorological Administration(KMA) and Korea Hydrographic and Oceanographic Agency(KHOA) were used. Reduced Major Axis(RMA) regression method was applied as regression analysis between the satellite wind data and in-situ measurements. As a general results, when wind speeds with wind directions from the offshore were compared between the satellite and in-situ buoy data, the correlations were higher and the root mean square errors were lower compared to the wind blows from the land.

장기 파랑관측자료 분석 및 천해파 수치실험에 의한 강릉 해역의 천해설계파

정원무(Jeong, Weon Mu),전기천(Jun, Ki Cheon),김건우(Kim, Gunwoo),오상호(Oh, Sang-Ho),류경호(Ryu, Kyong-Ho) 한국해안해양공학회 2012 한국해안해양공학회 논문집 Vol.24 No.5

본 연구에서는 강릉 해수욕장 전면에서 20년간 관측된 파랑자료의 극치분석을 통하여 재현빈도 10, 20, 30 및 50년의 천해설계파를 도출하였다. 이들을 수산청(1988) 및 한국해양연구원(2005)에 제시된 강릉 해역에 대한 재현빈도별 심해파 조건을 경계조건으로 천해파 모델인 SWAN을 사용하여 관측지점에서의 파고를 구한 값과 비교하였다. 그 결과 이러한 기존의 심해파 조건들로 계산한 강릉 해역의 천해파고는 관측치에 비해 상당히 작게 제시되었으며 그 차이는 재현빈도의 증가에 따라 커지는 것을 확인하였다. 한국해양연구원은 이전보다 상세한 격자와 WAM 모델을 사용하여 2004년 1월부터 2008년 8월까지의 역추산 자료를 생성하였으며, 이를 천해역의 관측 자료와 비교한 결과 1979~2003년의 자료에 비해 동계 폭풍파의 재현성이 크게 향상되었음을 확인하였다. 앞으로 2004년 이전에 대해서도 상세 격자와 WAM 모델을 사용한 역추산 자료의 생성 및 이를 사용한 심해파의 보완 작업이 필요한 것으로 사료된다. In this study, shallow-water design waves are calculated for the return period of 10, 20, 30, and 50 years, based on the extreme value analysis of the wave measurement data at Gangneung beach. These values are compared with the results of SWAN simulation with the boundary condition of the deep-water design waves of the corresponding return periods at the Gangneung sea area provided by the Fisheries Agency (FA, 1988) and Korea Ocean Research & Development Institute (KORDI, 2005). It is found that the shallow-water wave heights at Gangneung beach calculated by the deep-water design waves were significantly less than the observation data. As the return period becomes higher, the significant wave heights obtained by the extreme value analysis becomes higher than those computed by SWAN with the deep-water design waves of the corresponding return periods. KORDI computed the hindcast wave data from January 2004 to August 2008 by WAM with a finer-grid mesh system than those of previous studies. Comparisons of the wave hindcast results with the wave observation show that the reproducibility of the winter-season storm wave was considerably improved compared to the hindcast data from 1979 to 2003. Hereafter, it is necessary to carry out hindcast wave data for the years before 2004 using WAM with the finer-grid mesh system and to supplement the deep-water design wave.

동북아시아 해상에서의 태풍중심기압과 최대풍속의 경험적 관계식

강시환(See-Whan Kang),전기천(Ki-Cheon Jun),방경훈(Gyeong-Hun Bang),박광순(Kwang-Soon Park) 한국기상학회 2002 Asia-Pacific Journal of Atmospheric Sciences Vol.38 No.5

해상교통을 위한 국지정밀 해상풍 예측

박광순(Kwang-Soon Park),전기천(Ki-Cheon Jun),권재일(Jae-Il Kwon),허기영(Ki-Young Heo) 한국항해항만학회 2009 한국항해항만학회 학술대회논문집 Vol.2009 No.공동학술

지구온난화에 따른 해수면 상승과 태풍 강도의 증가는 연안역에 밀집한 주거 및 산업공간을 위협하는 요소로 최근 그 연구가 활발하게 진행되어 오고 있다. 본 연구에서는 안전한 해상교통 및 폭풍해일과 파랑예측을 위해서 반드시 필요한 해상풍에 대한 연구이다. 해상풍은 연안역에서의 자연재해를 유발하는 여러 요소 중에서 중요한 연구과제이나, 현재 기상수치모델에 의한 해상풍 및 해면기압은 시.공간적으로 불충분하다. 따라서, 중규모 기상 모형인 Weather Research and Forecasting (WRF)을 사용하여 우리나라 주변해역을 모두 포함하며, 약 9km 격자로 매일 두 번씩 72시간을 예보하는 해상풍을 산출하는 시스템을 구축하였다. 이어도 해양과학기지와 황해중부부이에서 실측한 해상풍과 검증한 결과 상당히 유의할 만한 결과를 얻었으며, 자료동화를 이용하여 향후에는 보다 정확한 해상풍을 산출할 계획이다. Sea level rise and increase of the typhoon/hurricane intensity due to global warmíηg have threaten coastal areas for residential and industrial and have been widely studied. In this study we showed our recent efforts on sea wind which is one of critical factors for safe maritime traffic and prediction for storm surges and waves. Currently, most of numerical weather models in korea do not have sufficient spatial and temporal resolutions, therefore we set up a find grid (about 9km) sea wind prediction system that predicts every 12 hours for three day using Weather Research and Forecasting (WRF). This system covers adjacent seas around korean peninsula Comparisons of two observed data, Ieodo Ocean Research station (IORS) and Yellow Sea Buoy (YSB), showed reasonable agreements and by data assimilation we will improve better accurate sea winds in near future.

황해.동중국해의 겨울철 취송 순환에 대하여: Part I. 조류에 의한 저면 마찰력의 영향

이종찬,김창식,정경태,전기천,Lee, Jong-Chan,Kim, Chang-Shik,Jung, Kyung-Tae,Jun, Ki-Cheon 한국해양과학기술원 2003 Ocean and Polar Research Vol.25 No.suppl3

The effect of bottom friction on the steady wind-driven circulation in the Yellow Sea and the East China Sea (YSECS) has been studied using a two-dimensional numerical model with and without tidal forcing. Upwind flow experiment in YSECS has also been carried out with a schematic time variation in the wind field. The surface water setup and circulation pattern due to steady wind forcing are found to be very sensitive to the bottom friction. When the effects of tidal currents are neglected, the overall current velocities are overestimated and eddies of various sizes appear, upwind flow is formed within the deep trough of the Yellow Sea, forming a part of the topographic gyre on the side of Korea. When tidal forcing is taken into account, the wind-induced surface elevations are smoothed out due to the strong tide-induced bottom friction, which is aligned almost normal to the wind stresses; weak upwind flow is farmed in the deep trough of the Yellow Sea, west and south of Jeju. Calculation with wind forcing only through a parameterized linear bottom friction produces almost same results from the calculation with $M_2$ tidal forcing and wind forcing using a quadratic bottom friction, supporting Hunter (1975)'s linearization of bottom friction which includes the effect of tidal current, can be applied to the simulation of wind-driven circulation in YSECS. The results show that steady wind forcing is not a dominant factor to the winter-time upwind flow in YSECS. Upwind flow experiment which considers the relaxation of pressure gradient (Huesh et al. 1986) shows that 1) a downwind flow is dominant over the whole YSECS when the northerly wind reaches a maximum speed; 2) a trend of upwind flow near the trough is found during relaxation when the wind abates; 3) a northward flow dominates over the YSECS after the wind stops. The results also show that the upwind flow in the trough of Yellow Sea is forced by a wind-induced longitudinal surface elevation gradient.

기후변화 시나리오에 따른 최대 가능 태풍강도 추정 및 이에 따른 폭풍해일고 양상 모의

윤종주(Jong-Joo Yoon),전기천(Ki-Cheon Jun),심재설(Jae-Seol Shim),박광순(Kwang-Soon Park) 한국해양환경·에너지학회 2012 한국해양환경·에너지학회지 Vol.15 No.4

준설 부유토사 발생량의 수리해석적 산정

강시환(See-Whan Kang),전기천(Ki-Cheon Jun),박광순(Kwang-Soon Park) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

The hydraulic analysis to obtain resuspension source strength of the dredged sediment was conducted by using the field data measured at Gunsan and Busan-Jinhe port dredging sites. Applying Kuo & Hayes(1991) analytical method, the suspended sediment concentration and ambient flow velocity measured along plume axis were used to obtain the hydraulic parameters of turbidity plume dispersion. The analytical solution was compared with the various field measurements including the data sets of the U.S.Army Corps of Engineer. The results were generally in a good agreement with field data in the SS concentration distributions at the dredging sites. The source strength of suspended sediment for each site was calculated using plume parameters. The result shows that the source strength was increased with the proportion to the in situ-ambient flow velocity, but was less dependent on the particle size of dredged sediment.

준설 탁도플륨거동의 수리학적 특성 해석

강시환(Kang See Whan),전기천(Jun Ki Cheon),강인남(Kang In Nam),한성대(Han Sung Dae) 대한토목학회 2004 대한토목학회논문집 B Vol.24 No.4B

연안 파랑 관측기간과 모수추정 오차 관계분석

조홍연(Cho, Hongyeon),정원무(Jeong, Weon-Mu),전기천(Jun, Ki Cheon) 한국해안해양공학회 2013 한국해안해양공학회 논문집 Vol.25 No.1

본 연구에서는 연안의 파후 자료를 이용하여 파랑 관측기간에 따른 오차범위의 정량적인 분석과 변화양상 분석을 수행하였다. 표본 관측기간은 1개월부터 6년까지 Bootstrap 기법을 이용하여 무작위로 추출하였다. 분석 결과, 전체적으로 관측기간이 1년보다 작은 경우에는 관측기간이 증가할수록 오차범위는 급격한 감소양상을 보이고 있으며, 관측기간이 1년 이상인 경우에는 관측기간의 증가에 따른 오차범위 감소 정도는 매우 완만한 것으로 파악 되었다. 절대적인 추정오차를 기준 파고 1 m 조건에서 10% 정도(±0.1m)로 가정하는 경우, 추정오차를 달성할 수 있는 최소 관측 기간은 거제 홍도 및 속초 지점은 2년 이상 자료로 이 조건을 만족하지만, 안마도 지점은 3년 이상의 관측 자료를 이용해야 이 조건을 만족하는 것으로 파악되었다. 한편 파고 백분위수는 값이 증가할수록 신뢰구간은 급격한 증가 양상을 보이는 반면, 주기 백분위수는 꼬리영역(2.5- & 97.5-백분위수 영역)을 제외하고는 0.5초 이내로 비교적 일정한 정도를 유지하고 있는 것으로 파악되었다. 항만가동률 평가에서 필요한 유의파고의 97.5-백분위수에 대한 정량적인 분석결과, 오차범위는 속초 0.75 m, 거제-홍도 0.5 m, 안마도 1.2 m 정도로 파악되었다. In this study, the quantitative analysis and pattern analysis of the error bounds with respect to recording period were carried out using the wave climate data from coastal areas. Arbitrary recording periods were randomly sampled from one month to six years using the bootstrap method. Based on the analysis, for recording periods less than one year, it was found that the error bounds decreased rapidly as the recording period increased. Meanwhile, the error bounds were found to decrease more slowly for recording periods longer than one year. Assuming the absolute estimate error to be around 10% (±0.1m) for an one meter significant wave height condition, the minimum recording period for reaching the estimate error for Sokcho and Geoje-Hongdo stations satisfied this condition with over two years of data, while Anmado station was found to satisfy this condition when using observational data of over three years. The confidence intervals of the significant wave height clearly show an increasing pattern when the percentile value of the wave height increases. Whereas, the confidence intervals of the mean wave period are nearly constant, at around 0.5 seconds except for the tail regions, i.e., 2.5- and 97.5-percentile values. The error bounds for 97.5-percentile values of the wave height necessary for harbor tranquility analysis were found to be 0.75 m, 0.5 m, and 1.2 m in Sokcho, Geoje-Hongdo, and Anmado, respectively.