• Title/Summary/Keyword: 역풍류

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A Simple Theoretical Model for the Upwind Flow in the Southern Yellow Sea (황해남부의 역풍류에 대한 단순 이론 모델)

  • 박용향
    • 한국해양학회지
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    • v.21 no.4
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    • pp.203-210
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    • 1986
  • A linear parallel transport model is formulated and applied to an idealized Yellow Sea, With this simple analytical model, the hither-to suspected upwind flow phenomena in the southern Yellow Sea can be reasonably explained. In deep waters where the local depth exceeds a critical depth (Hc=53m in the present model sea), pressure gradient force dominates over wind stress and contributes to an upwind flow. The estimated upwind flow velocity increases with wind speed and a maximum upwind flow occurs along the axis of the Yellow Sea embayment. For the typical south wind of 5-10 knots in summer, the upwind (southward) flow velocity along the axis of the Yellow Sea is estimated to be 1-5cm s$\^$-1/. While, for the typical north wind of 10-15 knots in winter, the upwind (northward) flow velocity is 5-12cm s$\^$-1/. These velocity ranges can be served as rough estimates for the intrusion velocity of the Yellow Sea Bottom Cold Water in summer and the Yellow Sea Warm Current in winter, respectively.

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Effect of Shantung Peninsula on the Development of Mean Upwind Flow in the Yellow Sea (황해의 역풍류 형성에 미치는 산동반도의 영향)

  • Seung, Young-Ho
    • 한국해양학회지
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    • v.30 no.6
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    • pp.537-542
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    • 1995
  • Effect of Shantung Peninsula on the development of mean upwind flow in the Yellow Sea in winter is analysed using a simple model. The results indicate that the disturbances generated by the Shantung Peninsula have a scale much larger than the basin scale whereas disturbances, if any, generated similarly on the other side of the trough has much smaller scale. The effect of Shantung Peninsula thus dominates over the whole basin and deflects westward the otherwise northward upwind flow.

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Seasonal Variations of Water Mass Distributions and Their Causes in the Yellow Sea, the East China Sea and the Adjacent Seas of Cheju Island (황해, 동지나해와 제주도 주변해역에서의 해수분포의 계절변화와 그 원인)

  • PANG Ig-Chan;RHO Hong-Kil;KIM Tae-Hee
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.2
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    • pp.151-163
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    • 1992
  • Seasonal variations of water mass distributions in the Yellow Sea, the East China Sea, and the adjecent seas of Cehju Island, are investigated. A common seasonal variation over these whole areas is shown. Warm and saline waters are extended northwestward into the Yellow Sea in winter and retreated back southeastward to the East China Sea in summer. Barotropic numerical model results suggest that monsoon winds could drive such seasonal variations. Upwind flows play an important role in the processes. In the numerical model results, upwind flows are shifted to China. It is due to energy dissipations by complicated coast lines and shallow bottom topographies in the northern part of the Yellow Sea. The shifted routes of upwind flows agrees well with that of the southward extensions of the Yellow sea Bottom Cold Waters in summer.

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Application of a Convolution Method for the Fast Prediction of Wind-Induced Surface Current in the Yellow Sea and the East China Sea (표층해류 신속예측을 위한 회선적분법의 적용)

  • 강관수;정경태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.7 no.3
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    • pp.265-276
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    • 1995
  • In this Paper, the Performance of the convolution method has been investigated as an effort to develop a simple system of predicting wind-driven surface current on a real time basis. In this approach wind stress is assumed to be spatially uniform and the effect of atmospheric pressure is neglected. The discrete convolution weights are determined in advance at each point using a linear three-dimensional Galerkin model with linear shape functions(Galerkin-FEM model). Four directions of wind stress(e.g. NE, SW, NW, SE) with unit magnitude are imposed in the model calculation for the construction of data base for convolution weights. Given the time history of wind stress, it is then possible to predict with-driven currents promptly using the convolution product of finite length. An unsteady wind stress of arbitrary form can be approximated by a series of wind pulses with magnitude of 6 hour averaged value. A total of 12 pulses are involved in the convolution product To examine the accuracy of the convolution method a series of numerical experiments has been carried out in the idealized basin representing the scale of the Yellow Sea and the East China Sea. The wind stress imposed varies sinusoidally in time. It was found that the predicted surface currents and elevation fields were in good agreement with the results computed by the direct integration of the Galerkin model. A model with grid 1/8$^{\circ}$ in latitude, l/6$^{\circ}$ in longitude was established which covers the entire region of the Yellow Sea and the East China Sea. The numerical prediction in terms of the convolution product has been carried out with particular attention on the formation of upwind flow in the middle of the Yellow Sea by northerly wind.

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Reproduction of Ocean Circulation around Korean Peninsula by using a Mesoscale Ocean Circulation Model (중규모 해양모형을 이용한 한반도 주변 해역 해양순환 재현)

  • Lee, Hae-Jin;Ahn, Joong-Bae
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.3
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    • pp.186-194
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    • 2000
  • In this study, the oceanic responses to given atmospheric boundary conditions are investigated using a mesoscale ocean circulation model. The numerical experiments are divided into two parts: One is, so called, spin-up experiment and the other is reproduction experiment. The spin-up experiment simulates climatic state of ocean by integrating the ocean model with upper boundary conditions of the monthly mean atmospheric climate data. In the reproduction experiment, for the reproduction of major oceanic changes around Korean Peninsula during the period of 1980-1998 (19 years), the model has been integrated under the boundary condition of the 19year monthly mean atmosphere data. The spined-up state of ocean generated from the spin-up experiment is assigned to the initial boundary condition of the reproduction experiment. In the spin-up experiment, the model properly simulates the major features of circulation structure around Korean Peninsula; such as separation of East Korean Warm Current (EKWC), formation of the polar front, cold water band associated with the small scale eddies in the East Sea, the formation of front along west coast, and the seasonal variation of circulation pattern caused by changing upwind current in the West Sea. In the reproduction experiment, the model has shown the interannual sea surface temperature variations and a warming trend of about 0.5$^{\circ}$C during the period around Korean Peninsula, as in the case of the observation. Therefore, it is concluded that the model is capable of simulating not only the mean states but also the variabilities of ocean under the given atmosphere boundary conditions.

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Coastally Trapped Waves over a Double Shelf Topography(III) : Forced Waves and Circulations Driven by Winds in the Yellow Sea (양향성 대륙붕의 대륙붕파 (III): 강제파와 황해에서의 바람에 의한 해수순환)

  • PANG Ig-Chan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.6
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    • pp.457-473
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    • 1992
  • The first order wave equation over a double shelf has wind stresses on both coastal boundaries and wind stress curl forcing across the shelf. In the Yellow Sea, the effect of wind stress curl can be neglected as a forcing of shelf waves. The decay distance of Kelvin waves is much greater than that of continental shelf waves so that Kelvin waves are transmitted nearly intact through the northern embayment. The numerical method of characteristics has been modified to accomodate wave propagation of opposite directions. Using a little more realistic coastline, the wave model hindcast has been improved for current velocity, but hardly for sea level. It means that Kelvin waves, which mainly determine sea levels, are affected little by the change of bottom slope. For a better hindcast of sea level, input energy of Kelvin waves transmitted from the East China Sea is needed. The basic structure of downwind flows along the coasts and upwind flows along the trough supports the seasonal circulations driven by monsoon winds in the Yellow Sea.

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Water Masses and Frontal Structures in Winter in the Northern East China Sea (동중국해 북부해역의 겨울철 수계와 전선구조)

  • 손영태;이상호;이재철;김정창
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.8 no.3
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    • pp.327-339
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    • 2003
  • During the winter in February 1998, January and April 1999, interdisciplinary research was conducted in a large area including the South Sea of Korea and northern East China Sea to examine distribution and structure. Water masses identified from the observed data are Warm Water originated from Tsushima Warm Current, Yellow Sea Cold Water (Northern or Central Cold Water) and Korean Southern Sea Cold Water. In the southern Yellow Sea, Warm Water originated from Tsushima Warm Current, flowing into the Cheju Strait after turning around the western Cheju Island, makes a front of '┍' shape, which is bounded by the Yellow Sea Central Cold Water in the southern part of Daeheuksan Island and by the Yellow Sea Northern Cold Water in the eastern part of the Yangtze Bank. This front changes its corner shape and position with strength of the warm water extension toward northwestern Yellow Sea. The position and structure of the fronts off the southwestern tip of the Korean peninsular and near the Yangtze Bank varies with observation period. In the front in the South Sea of Korea, cold coastal water which if formed independently due to local cooling, ,sinks along the sloping bottom. We explained the processes of variations in the distribution and structure of these winter fronts in terms of up-wind and down-wind flow by the seasonal monsoon, heat budget through the sea surface and density difference across the fronts.

On the Wintertime Wind-driven Circulation in the Yellow Sea and the East China Sea : Part I. Effect of Tide-induced Bottom Friction (황해.동중국해의 겨울철 취송 순환에 대하여: Part I. 조류에 의한 저면 마찰력의 영향)

  • Lee, Jong-Chan;Kim, Chang-Shik;Jung, Kyung-Tae;Jun, Ki-Cheon
    • Ocean and Polar Research
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    • v.25 no.spc3
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    • pp.361-371
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    • 2003
  • 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.

Assumptions on the Location of Changokbyeong and Saahm Park Soon's Garden Remains (창옥병(蒼玉屛)의 위치 비정(比定) 및 사암(思菴) 박순(朴淳)의 정원유적 연구)

  • Rho, Jae-Hyun;Park, Joo-Sung;Choi, Jong-Hee
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.34 no.4
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    • pp.37-50
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    • 2016
  • Recognizing the problem of fallacy in geographical name of Changokbyeong(蒼玉屛), assumption has been made on the location of Changokbyeong through literature research on antique maps, ancient paintings, and old prose, through field survey on rock inscriptions and landscape characteristics, and through interviews with local people. Furthermore, Baegyeonwa, the Cuckoo Hut, and Iyangjung(二養亭), an annex to the cottage, both of which were managed by Saahm Park Soon(思菴 朴淳), the Subject of Jouissance, were studied in depth with emphasis on the spatial structure as well as special features of the area as a garden. The major findings are as follows: Changokbyeong is a spatial threshold that imparts a sense of unity with Okbyeng seowon(玉屛書院) and indeed Changokbyeong is presumed to have been the frontal river terrace of Okbyeng seowon according to the analysis of antique maps and rock inscriptions. This ancient location and the Ogari Stone Wall, the present day Changokbyeong, are only 460m away so that both areas are considered as falling under the influence of Changokbyeong landscape. The expression "Changokbyeong Geupsangeum(蒼玉屛及散襟)" written in an old prose tells us that the high rock wall with Sangeumdae inscribed on the rock might be the rock wall of Changokbyeong. In addition, while not a single rock inscription has been found on the Ogari Stone Wall, 11 rock inscriptions designed and ordered by Saahm Park Soon, the Subject of Jouissance, are found on every corner of the high rock wall standing in front of Okbyeng seowon, 8 of those 11 being place names and recitative poems(known as Jeyeongsi: 題詠詩) in close formation resembling the handwritings in a little notebook. This provides a strong evidence for assuming the location of Changokbyeong to be the frontal river terrace of Okbyeng seowon. The "Songgyun Jeoljo Suwol Jeongshin(松筠節調 水月精神)" rock inscription on Changokbyeong should be considered as the stamping ground and as the symbolic language of Changokbyeong that bears the high character and nobility of the Subject of Jouissance, Saahm Park Soon. The inscription should also be recognized as the handwritings of Wooahm Song Si-Yeol(尤庵 宋時烈) correcting the misconceptions that persisted until today. Meanwhile, the garden remains of Saahm's Changokbyeong are composed of four sites: Sangeumdae-Sugyeongdae-Cheonghakdae-Baekhakdae from the left. At the back of Sangeumdae, there is the original house, the Baegyeonwa(拜鵑窩), and on the fantastically shaped stone wall at the left of Baekhakdae, there is the annex, the Iyangjung, together creating a landscape composition that overlooks the splendor of the Ogari Stone Wall. The Iyangjung is located on the highest spot to the left of the four sites, and it is believed to have been a little outhouse and library for Saahm which remains to the present day as a place where Saahm's character can be felt. The drinking plates[窪樽] made of rock that are affectionately arranged on the broad flat rock in front of Iyangjung is part of the garden remains that reflects the artistic taste of Saahm regarding the drinking culture at the time.

Lew Seung Kug's Recognition on Relations between Juhng-yaug and History of Korean Thoughts (도원 류승국의 정역(正易)과 한국사상사의 상호 매개적 인식)

  • Yi, Suhngyohng
    • The Journal of Korean Philosophical History
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    • no.50
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    • pp.201-234
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    • 2016
  • This thesis examined interpreting methodology of Do Won Lew Seung Kug(1923~2011) is based on the principle of Juhng-yaug. His lifelong academic aim was searching for the theory that enables global community to co-exist peacefully through humanitarianism that leads to reconciliation and mutual benefits. The research of the history of Korean thoughts provided him with the clue for his theory. According to Do Won, Korean thoughts pursue the Juhng-yaug's value of 'Yin and Yang accordance' rather than the I-Ching's value of 'suppress Yin and elevate Yang'. He furthermore asserts the concept of the middle (中), which harmonizes the two extremes by human beings as main agents, has been consistently observed from the action of divination during the ancient period through Juhng-yaug in the late 19th century. Do Won identifies 'human maturity that integrates the extremely conflicting insistences and values and seeks to be reconciled' as the basic character of Korean thoughts. He explains 'Hongikingan[弘益人間, becoming beneficial to the human world] is the idea that embraces the conflicting values symbolized by heaven and the earth. He also illuminates that Choe Chi Won(崔致遠)'s created Poongliu Do by integrating heterogeneity among Confucianism, Buddhim, and Daoism and it was attainable through the various works of mature human beings. Both Toe Gye' s philosophy of Ingeuk(人極, the Great Ultimate of Person) and the concept of Innaecheon(人乃天, Human Being right is Heaven) of Donghak are excellent examples of Humanitarianism that sublate two extremes. In Korea, the prototype of this thought has penetrated its entire history in the various circumstances of the period. The grand finale is Juhng-yaug of which the pursued values are 'Yin and Yang accordance' and mature humanitarianism revealed by the thoughts of the Person of the Central Ultimate (皇極人,至人) and Central Ultimate (皇極). Therefore, Humanitarianism in Korean thoughts clearly makes its appearance by the time of Juhng-yaug and it functions as a keyword to illuminate the entire history of Korean thoughts in reverse.