Probabilistic Assessment of Wave Overtopping of Nampo Dike in the West Coast of Korea     

郄禄文  崔秉昊  谢世楞 《中国海洋工程》2008,22(3):409-420

The Nampo dike, which is located at the west coast of Korea, was destroyed by wave overtopping during the storms on 30 August and 17 September in 1959. In this paper, is performed the probabilistic assessment of wave overtopping of Nampo dike by use of Owen model, Van der Meer ＆ Janssen model and Hedges ＆ Reis model for wave overtopping of seawall. Based on the available tidal and wave data for storm surges in 1989, the risk assessment of wave overtopping of the Nampo dike has been carried out by both Level Ⅱ and Level Ⅲ reliability methods. The calculated resuhs show the general agreement of failure probability between the two methods. By utilizing the rehabilitated cross section of Nampo dike, the failure probability of wave overtopping for the Nampo dike after rehabilitation will be rapidly reduced to that of initial design at crest level of 9.0 m with the improved slope from 1 ： 2 to 1 ： 4 at seaside. Since the sea level may only rise 1.0 m in the next few decades, the failure probability of Nampo dike will be still in the safe range.  相似文献   

Petrogenesis and Solidification Depth of the Jurassic Daebo and Cretaceous Bulguksa Granitic Rocks in South Korea     

Etsuo UCHIDA  Seon‐Gyu CHOI  Daisuke BABA  Yusuke WAKISAKA 《Resource Geology》2012,62(3):281-295

We investigated the Jurassic Daebo and Cretaceous Bulguksa granitic rocks in South Korea. The former are distributed mainly in the Gyeonggi and Yeongnam massifs and the latter are present in the Gyeongsan basin and Ogcheon belt. The Daebo granitic rocks generally are of ilmenite series and I to S type. These rocks are associated with Au–Ag hydrothermal deposits, whereas the Bulguksa granitic rocks are of magnetite series and I type, and are associated with Pb–Zn, Cu and Mo–W hydrothermal deposits, as well as Au–Ag hydrothermal deposits. The Daebo granitic rocks show adakitic signatures in their chemical compositions. They are considered to have been derived from partial melting of the thick lower continental crust. Conversely, the Bulguksa granitic rocks in the Gyeongsan basin are non‐adakitic and are considered to have been derived from partial melting of a mantle wedge. Magmas of the Daebo granitic rocks formed at relatively shallow levels, but solidified at deep levels compared with those of the Bulguksa granitic rocks. The Bulguksa granitic rocks in the central to western Ogcheon belt are considered to have been formed by fractionation of magmas derived from partial melting of continental crust. The total Al contents of biotite and hornblende in the granitic rocks increased, with the Bulguksa granitic rocks in the Gyeongsan basin < the Bulguksa granitic rocks in the Ogcheon belt and Gyeonggi and Yeongnam massifs and the Daebo granitic rocks in the Ogcheon belt < the Daebo granitic rocks in the Gyeonggi and Yeongnam massifs. This order corresponds to an increase in solidification depth.  相似文献   

根据重力数据研究黄海周边断裂带在海区的延伸   总被引：43，自引：10，他引：43       下载免费PDF全文

郝天珧  Suh Mancheol  王谦身  CHOI Suckwon  江为为  宋海斌  阎晓蔚  刘建华  姚长利 《地球物理学报》2002,45(3):385-397

根据黄海及周边地区的布格重力资料,通过解析延拓、目标场提取、任意水平方向导数计算、离散小波变换等处理,得到各种有关断裂的信息.经过与地质资料综合分析,选择123°E经线为典型剖面,以地震资料建立初始模型,对该剖面进行重力正反演迭代拟合,最终得到各模块的密度参数及分布,并在此基础上分析了研究区主要断裂的地质地球物理特征,给出了研究区的断裂带、块体结合带分布图.重点对朝鲜半岛西缘断裂带和五莲-青岛-荣城断裂带进行了讨论,提出五莲-青岛-荣城断裂带并未进入朝鲜半岛与临津江断裂带相连.认为朝鲜半岛西缘断裂带西侧属于扬子块体的部分曾受北向应力作用向北发生了平移.由五莲-青岛-荣城断裂带和南黄海北部断裂带、朝鲜半岛西缘断裂带及济州岛南缘断裂带共同组成的断裂带应该是中朝与扬子块体之间的结合带.  相似文献   

Comparative simulation study of effects of eddy-topography interaction in the East/Japan Sea deep circulation     

CHOI Youngjin 《海洋学报(英文版)》2015,34(7):1-18

In this study the structure and seasonal variations of deep mean circulation in the East/Japan Sea (EJS) were numerically simulated using a mid-resolution ocean general circulation model with two diffe...  相似文献   

Effects of Wind Fences on the Wind Environment around Jang Bogo Antarctic Research Station     

Jang-Woon WANG  Jae-Jin KIM  Wonsik CHOI  Da-Som MUN  Jung-Eun KANG  Hataek KWON  Jin-Soo KIM  Kyung-Soo HAN 《大气科学进展》2017,34(12):1404-1414

This study investigated the flow characteristics altered by Jang Bogo Antarctic Research Station using computational fluid dynamics(CFD) modeling. The topography and buildings around Jang Bogo Station were constructed with computeraided-design data in the CFD model domain. We simulated 16 cases with different inflow directions, and compared the flow characteristics with and without Jang Bogo Station for each inflow direction. The wind data recorded by the site's automatic weather station(AWS) were used for comparison. Wind rose analysis showed that the wind speed and direction after the construction of Jang Bogo Station were quite different from those before construction. We also investigated how virtual wind fences would modify the flow patterns, changing the distance of the fence from the station as well as the porosity of the fence. For westerly inflows, when the AWS was downwind of Jang Bogo Station, the decrease in wind speed was maximized(-81% for west-northwesterly). The wind speed reduction was also greater as the distance of the fence was closer to Jang Bogo Station. With the same distance, the fence with medium porosity(25%–33%) maximized the wind speed reduction.These results suggest that the location and material of the wind fence should be selected carefully, or AWS data should be interpreted cautiously, for particular prevailing wind directions.  相似文献   

Possibility of Solid Hydrometeor Growth Zone Identification Using Radar Spectrum Width     

Sung-Ho SUH  Eun-Ho CHOI  Hong-Il KIM  Woonseon JUNG 《大气科学进展》2023,40(2):317-332

In this study, the correlation between simulated and measured radar velocity spectrum width(σ_v) is investigated. The results show that the dendrites growth zones(DGZs) and needles growth zones(NGZs) mostly contain dendrites(DN) and needles(NE), respectively.Clear σ_v zones(1.1 < σ_v(m s^–1) < 1.3 and 0.3 < σ_v(m s^–1) < 0.7 for the DGZ and NGZ, respectively) could be identified in the case studies(27 and 28 February 2016) n...  相似文献   

Effect of the Bottom Topography on Tsunami Propagation in the East （Japan） Sea     

CHOI Byung-Ho  ;PELINOVSKY Efim  ;JEON Chul-Kyoo  ;KIM Kyeong-Ok 《中国海洋工程》2008,22(2):277-290

A study of tsunami events in the East （Japan） Sea using continuous Galerkin finite element model, aiming at reproducing tsunami waves generated by underwater earthquakes in 1983 and 1993 respectively has been performed focusing on the geographic extent of a topographic feature in the East （Japan） Sea. Numerical models can be the proper tools to study the combined effects of realistic topography. Subsequently, using the FEM based two-dimensional model we have simulated the smoothed and flattened topographic effects by removal of Yamato Rise and seamounts for the cases of tthe 1983 Central region earthquake tsunami and the 1993 southwestern Hokkaido earthquake tsunami. The results have shown that there will be higher tsunamis along the eastern coasts of Korea in general except some areas, like Sokcho with removal of topographic highs, thus providing complicated bottom topography of the East （Japan） Sea as effective tsunami energy scattering.  相似文献   

Debris flow impact on flexible barrier: effects of debrisbarrier stiffness and flow aspect ratio     

SONG Dong-ri  ZHOU Gordon G.D.  CHOI Clarence Edward  ZHENG Yun 《山地科学学报》2019,(7)

Conventionally, flexible barriers are rated based on their ability to resist a free-falling boulder with a particular input energy. However, there is still no well-accepted approach for evaluating performance of flexible barrier under debris flow impact. In this study, a large-nonlinear finite-element model was used to back-analyze centrifuge tests to discern the effects of impact material type, barrier stiffness, and flow aspect ratio(flow height to flow length) on the reaction force between the impacting medium and flexible barrier. Results show that, in contrast to flexible barriers for resisting rockfall, the normal impact force induced by the highly frictional and viscous debris is insensitive to barrier stiffness. This is because the elongated distributions of kinetic energy are mainly dissipated by the internal and boundary shearing, and only a small portion is forwarded to the barrier. Furthermore, a new stiffness number is proposed to characterize the equivalent stiffness between a debris flow or a boulder, and a flexible barrier. Under the circumstance of an extremely elongated debris flow event, i.e., low aspect ratio, the load on a barrier is dominated by the static component and thus not sensitive to the barrier stiffness.  相似文献   

Physiological differences in the growth and maturation of Eisenia bicyclis and Ecklonia cava gametophytes in Korea     

Han Gil CHOI  Da Vine JEON  Seo Kyoung PARK  GAO Xu 《海洋湖沼学报（英文）》2019,(2):657-664

The objective of this study was to examine the eff ects of temperature and light intensity on growth of female gametophytes of Eisenia bicyclis and Ecklonia cava and responses of these female gametophytes to Fe addition and daylength. Female gametophytes of each species were cultured at four temperatures (10, 15, 20, and 25°C) and under a combination of four light intensities (10, 20, 40, and 80 μmol photons/(m^2 ·s)) with two temperatures (15 and 20°C for E i . bicyclis;20 and 25°C for E c . cava ) to clarify their optimal growth conditions. Growth and maturation of female gametophytes of these two species under a combination of five Fe-EDTA concentrations (0, 1, 2, 4, and 8 μmol/L) and three daylengths (10, 12, and 14 h) were also examined. The growth of E i . bicyclis gametophyte was maximal at approximately 15–20°C, 20 μmol photons/(m^2 ·s), Fe-EDTA concentration of 8 μmol/L and daylengths of 12–14 h. While E c . c ava gametophytes showed optimal growth at approximately 20–25°C, 20 μmol photons/(m^2 ·s), Fe- EDTA concentration of 8 μmol/L and daylength of 14 h. Maturation of gametophytes was enhanced at Fe-EDTA concentration of 4 μmol/L for E i . bicyclis and at 2 μmol/L for E c . c ava . In conclusion, optimal growth temperatures and Fe-EDTA concentrations for maturation of E i . bicyclis and E c . c ava gametophytes were diff erent. Higher optimal growth temperature for E c . c ava gametophytes may contribute to its wider geographical distribution compared to E i . bicyclis which has restricted habitats in Korea. This suggests that addition of Fe ion could be used to recover beds of these two species in barren grounds of Korea.  相似文献   

Characteristics and Nonlinear Growth of the Singular Vector Related to a Heavy Rainfall Case over the Korean Peninsula     

Yonghan CHOI  Joowan KIM  Dong-Kyou LEE 《大气科学进展》2012,29(1):10-28

In this study,singular vectors related to a heavy rainfall case over the Korean Peninsula were calculated using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) adjoint modeling system.Tangent linear and adjoint models include moist physical processes,and a moist basic state and a moist total energy norm were used for the singular-vector calculations.The characteristics and nonlinear growth of the first singular vector were analyzed,focusing on the relationship between the basic state and the singular vector.The horizontal distribution of the initial singular vector was closely related to the baroclinicity index and the moisture availability of the basic state.The temperature-component energy at a lower level was dominant at the initial time,and the kinetic energy at upper levels became dominant at the final time in the energy profile of the singular vector.The nonlinear growth of the singular vector appropriately reflects the temporal variations in the basic state.The moisture-component energy at lower levels was dominant at earlier times,indicating continuous moisture transport in the basic state.There were a large amount of precipitation and corresponding latent heat release after that period because the continuous moisture transport created favorable conditions for both convective and nonconvective precipitation.The vertical propagation of the singular-vector energy was caused by precipitation and the corresponding latent heating in the basic state.  相似文献