감조하천에서 조석 전파 및 조석비대칭

강주환,조홍연,Kang, Ju Whan,Cho, Hong-Yeon 한국수자원학회 2021 한국수자원학회논문집 Vol.54 No.6

In order to examine the characteristics of tidal wave from the estuary to upsteam of tidal river, tidal asymmetry was identified based on analysis of the harmonic constants of M2 and M4 tidal constituents in the domestic western coastal regions. As shallow water tide is greatly developed in the estuary, flood dominance in Han River and Keum River, and ebb dominance in Youngsan River are developed. These tidal asymmetries can be reconfirmed by analyzing the tidal current data. Unlike having reciprocating tidal current patterns in Keum and Youngsan estuaries, rotaing tidal current pattern is shown in the Han River estuary due to the complex topography and waterways around Ganghwa Island area. However, when residual current is removed, flood dominance is shown in consistency with the tide data. The tidal asymmetry in the estuary tends to intensify with the growth in shallow water tide as the tidal wave propagates to upstream of tidal river. Energy dissipation, in shallow Han River and Keum River classified as SD estuaries, is very large regarding bottom friction characteristics. On the other hand, the deep Youngsan River, classified as a WD estuary, shows less energy dissipation.

음해법을 이용한 천수방정식의 수치해석

강주환,박상현,이길성,Kang, Ju Whan,Park, Sang Hyun,Lee, Kil Seong 대한토목학회 1993 대한토목학회논문집 Vol.13 No.3

Recently, ADI scheme has been a most common tool for solving shallow water equation numerically. But ADI models of tidal flow is likely to cause so called ADI effect in such a region of the Yellow Sea which shows complex topography and has submarine canyons especially. To overcome this, a finite difference algorithm is developed which adopts fully implicit method and preconditioned conjugate gradient squared method. Applying the algorithm including simulation of intertidal zone to Sae-Man-Keum. velocity fields and flooding/drying phenomena are simulated well in spite of complex topography.

서·남해안 조석-해일 비선형성 발생양상

강주환,김양선,윤영관,심재설,Kang, Ju Whan,Kim, Yang-Seon,Yoon, Young-Kwan,Shim, Jae-Seol 한국해안·해양공학회 2014 한국해안해양공학회 논문집 Vol.26 No.6

Hourly tide-gauge data at 10 tide stations along the West/South coasts were analysed statistically for tidesurge interaction. Interactions were found at all stations except Busan, prominently at the western tip of the South coast near Mokpo and Wando. A well-known interaction pattern which occurs at flood tide was found rarely at domestic coasts, while another pattern of the tide-modulated surge which occurs at low tide was detected frequently. In addition, a new interaction pattern which occurs at ebb tide is discovered. This pattern is found at Mokpo where the ebb dominance is prominent. Finally, the skew surge could be considered as a tool coping with such interactions.

조석-해일 특성을 반영한 극치해면고 산정

강주환(Ju Whan Kang),김양선(Yang-Seon Kim) 한국해안해양공학회 2018 한국해안해양공학회 논문집 Vol.30 No.3

경험모의기법을 통해 국내 서남해안의 조석과 해일특성을 고찰하였다. 그 결과 인천, 군산, 목포, 완도 등은 조석지배해역이고 여수, 통영, 부산 등은 해일지배해역으로 구분되었다. 조석지배해역에서는 태풍해일이 발생하지 않아도 50년 이하의 빈도를 갖는 극치해면고가 형성될 수 있는 반면 해일지배해역에서는 10년 빈도에서만 태풍해일 없이 극치해면고가 형성될 수 있는 양상을 보이고 있다. 각 해역에서 빈도별로 평균적인 상황으로 어느 정도의 조위에 어느 정도의 해일이 겹쳐 극치해면고가 형성되는지 고찰한 결과 이 역시 해역별로 구분되는 특성을 보이고 있다. 이와 함께 설계조위 산정을 위한 세 가지 방법을 비교고찰한 결과 약최고고조위방법은 과다설계의 우려가 매우 큰 비현실적인 결과를 보이고 있으며, 확률분포함수방법은 대형태풍이 소조기나 저조시 발생할 경우 해당자료가 결과에 반영되지 않거나 매우 축소된 결과가 도출될 우려가 있다는 단점이 있다. 이러한 단점들을 해결함과 동시에 서해안과 같이 조석이 지배적인 해역에 적합한 방법으로 경험모의기법의 적용성을 확인하였다. Tide-surge characteristics of the West/South domestic coasts were analyzed with a tool of EST (empirical simulation technique). As a result, stations of Incheon, Gunsan, Mokpo and Busan are categorized as tide-dominant coasts, while Yeosu, Tongyoung and Busan are as surge-dominant coasts. In the tide-dominant coasts, extreme sea level of less than 50-yr frequency is formed without typhoon-surge, while only 10-yr extreme sea level is formed in the surge-dominant coasts. As the results of casual condition of extreme sea level formation considering the relative degree of surge on tide, the regional characteristics were detected also. Three methods for estimating the design tide level were compared. The AHHW method shows an unrealistic outcomes of the concern of over estimate design. Furthermore, the probability distribution function method has been concerned as causing missing data if a huge typhoon occurs in a neap tide or a low tide. To cope with these drawbacks, the applicability of the EST method is proved to be suitable especially in tide-dominant coasts.

표준태풍 모의를 통한 해일고 빈도해석

강주환(Ju Whan Kang),김양선(Yang-Seon Kim) 한국해안해양공학회 2016 한국해안해양공학회 논문집 Vol.28 No.5

빈도별 최대풍속을 발생시키는 태풍조건을 역추적함으로써 빈도별 표준태풍을 생성할 수 있다(Kang et al., 2016). 본 연구에서는 이렇게 얻어진 표준태풍의 해일모의를 통해 서해안 영광지역의 해일고 빈도해석을 수행하는 방안을 제시하고자 한다. 본 연구에 사용된 모형은 MIKE21모형으로서 태풍 BOLAVEN(1215)에 대한 검증 결과 서해안 여러 지역에서 관측결과와 비교적 잘 일치하는 결과를 얻었다. 서해안 태풍해일특성을 감안하여 경로변경을 설정한 후 빈도별 해일고를 구한 결과는 관측치로부터 산정된 결과와 부합하는 결과를 보이고 있다. 이 방법은 관측자료가 충분치 않은 곳에서 수많은 태풍에 의한 해일모의를 수행하는 기존 방법에 비해 빈도별로 한 개의 태풍만을 대상으로 하므로 매우 효율적인 방법이다. A standard typhoon, which results in extreme wind speeds having various return period, can be reconstructed by combination of typhoon parameter informations(Kang et al., 2016). The aim of this study is to present a kind of surge-frequency analysis method by numerical simulation of a standard typhoon at Yeonggwang. MIKE21 was adopted as a numerical model and was proved to simulate the surge phenomena of the typhoon BOLAVEN(1215) well at several sites of the Western Coast. The simulation results with change of typhoon track which reflects typhoon-surge characteristics of the Western Coast show to have something in common with the observational results. This method is considered to be very efficient method on the point of simulating only one typhoon, while existing methods need to simulate a lot of typhoons.

방조제 건설 전후에 목표해역의 오염물질 확산 메커니즘

강주환(Ju Whan Kang),임병선(Byung Sun Ihm),이점숙(Jeom Sook Lee),김종욱(Jong Wook Kim),임현식(Hyun Sig Lim),김하송(Ha Song Kim) 한국환경생물학회 1998 환경생물 : 환경생물학회지 Vol.16 No.4

The pH, Do, COD, NH_4-N, NO_3-N and T-P of sea water were measured in both sites effluencing sewage and passing through salt marsh, and also the RMA and FIT model were applied to the Mokpo coastal zone to analyze the changes of pollutant dispersion mechanism by constructions of the seawalls. The nitrogen source of sea water in the sites passing through salt marsh increased but COD and T-P decreased. After constructions of the Youngam/Kumho seawalls, tidal velocity was decreased and exchange of sea water was very increased between the north of the Mokpo coastal zone and the 4th seawall region and was very decreased between the south of the Mokpo coastal zone and outer sea water. The results of simulation on diffusion of organic matter indicate that most region of the Mokpo coastal zone will suffer deepened contamination after the constructions.

서남해안의 해수면 상승

강주환(Kang Ju Whan),문승록(Moon Seung Rok),오남선(Oh Nam Sun) 대한토목학회 2005 대한토목학회논문집 B Vol.25 No.2B

조석/해일 환경변화를 감안한 고극조위 빈도분석

강주환(Kang Ju Whan),문승록(Moon Seung Rok),박선중(Park Seon Jung) 대한토목학회 2006 대한토목학회논문집 B Vol.26 No.1B

지구온난화에 의한 전지구적 해수면 상승과 더불어 하구언/방조제와 같은 해안구조물 건설이후 군산 및 목포해역에서의 고극조위는 지속적인 증가추세를 보이고 있다. 본 연구에서는 선형회귀분석방법을 이용하여 장기적 변화에 의한 고극조위 상승량과 건설에 의한 고극조위 상승량을 정량적으로 분리한 후, 이들 해역에서 발생하고 있는 고극조위 상승원인을 분석하였다. 목포해역을 대상으로 M₂ 분조에 대한 수치실험 결과 하구언과 방조제 건설로 인한 조석확폭현상은 주로 목포구의 TCE 기능의 소멸로 인해 발생한 것으로 확인되었다. 조석확폭은 조간대효과에 따라 극조일수록 더욱 크게 나타나 목포해역의 해일 위험성이 매우 높아진 상태가 되었다. 또한 하구언 및 방조제 건설에 따라 조석환경에 변화가 야기되어 건설시기 전후로 조위자료의 동질성이 결여된 곳에 효율적으로 적용할 수 있는 빈도분석 방법을 적용하여 빈도별 고극조위를 산정하였다. Due to both global warming and constructions of seadike/seawalls, continuously or abruptly rising tendencies of extreme high water levels have been detected at Kunsan and Mokpo harbors. This paper deals firstly with the separation of each effect, namely global warming effect and construction effect, on increases of water level quantitatively by a linear regression method. And then, it can be explained why and how the extreme high water levels had been risen just after constructions at both harbors. A numerical simulation of M₂ tidal constituent at Mokpo coastal zone shows that the tidal amplification by constructions is mainly due to the extinguishment of TCE at Mokpogu. The tidal flat effect makes the amplification more deepen at spring tide or extreme high tide, which results in the increase of inundation risk at Mokpo harbor. A frequency analysis method is applied, which is shown to be effective at such a site of having non-homogeneous tidal data due to constructions as Mokpo harbor.

천해조가 발달된 하구에서의 조석파 전파특성

강주환(Kang Ju Whan),김병옥(Kim Byoung Ok),문승록(Moon Seung Rok) 대한토목학회 2000 대한토목학회 학술발표회 논문집 Vol.2000 No.3

국내 연안의 해일강도 특성

강주환(Kang, Ju-Whan),김양선(Kim, Yang-Seon),조홍연(Cho, Hong-Yeon),심재설(Shim, Jae-Seol) 한국해안해양공학회 2011 한국해안해양공학회 논문집 Vol.23 No.6

20개 검조소 자료 분석을 통해 국내연안에서 해일강도특성을 파악하고자 하였다. 조위편차 자료에 대한 통계분석 결과 해역별로 해일발생 특성이 구분되는 경향을 보였으며 서해안의 조위편차가 남해안 및 동해안에 비해 월등히 큰 것으로 나타났다. 30 cm 이상에 해당하는 해일고에 대해서 해일강도를 분석하였는데 태풍에 의한 해일을 분리한 결과 서해안의 경우 해일 발생이 주로 계절풍에 기인하여 동절기에 크게 나타나고 있는 반면 남해안과 동해안의 경우에는 계절풍의 영향은 미미하고 하절기 태풍에 의한 영향이 지배적인 것으로 나타나고 있다. EOF 분석을 통해 유추된 결과 역시 1차 고유벡터의 경우 서해안 지점에서 두드러진 값을 나타내는 등 일맥상통한 결과를 보이고 있다. Characteristics of nearshore surge intensity were investigated by analyzing the tide data at 20 tidal stations. Statistical analysis of the surge data show that surge heights at the western coast are far greater than those at southern and eastern coasts, implying that each coast has its own classified characteristics. Surge height data greater than 30 cm were chosen and their intensities were calculated, and then, typhoon-induced surges were separated. The results show that while surge intensity at the western coast is conspicuous in winter due to the monsoon, it is conspicuous in summer due to the typhoon at other coasts. EOF analysis show that the 1st eigenvector at the western coast is prominent, which is considered to be consistent with above mentioned results.