• Title/Summary/Keyword: Korea hydrographic and oceanographic administration

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Characteristics of the Differences between Significant Wave Height at Ieodo Ocean Research Station and Satellite Altimeter-measured Data over a Decade (2004~2016) (이어도 해양과학기지 관측 파고와 인공위성 관측 유의파고 차이의 특성 연구 (2004~2016))

  • WOO, HYE-JIN;PARK, KYUNG-AE;BYUN, DO-SEONG;LEE, JOOYOUNG;LEE, EUNIL
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.23 no.1
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    • pp.1-19
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    • 2018
  • In order to compare significant wave height (SWH) data from multi-satellites (GFO, Jason-1, Envisat, Jason-2, Cryosat-2, SARAL) and SWH measurements from Ieodo Ocean Research Station (IORS), we constructed a 12 year matchup database between satellite and IORS measurements from December 2004 to May 2016. The satellite SWH showed a root mean square error (RMSE) of about 0.34 m and a positive bias of 0.17 m with respect to the IORS wave height. The satellite data and IORS wave height data did not show any specific seasonal variations or interannual variability, which confirmed the consistency of satellite data. The effect of the wind field on the difference of the SWH data between satellite and IORS was investigated. As a result, a similar result was observed in which a positive biases of about 0.17 m occurred on all satellites. In order to understand the effects of topography and the influence of the construction structures of IORS on the SWH differences, we investigated the directional dependency of differences of wave height, however, no statistically significant characteristics of the differences were revealed. As a result of analyzing the characteristics of the error as a function of the distance between the satellite and the IORS, the biases are almost constant about 0.14 m regardless of the distance. By contrast, the amplitude of the SWH differences, the maximum value minus the minimum value at a given distance range, was found to increase linearly as the distance was increased. On the other hand, as a result of the accuracy evaluation of the satellite SWH from the Donghae marine meteorological buoy of Korea Meteorological Administration, the satellite SWH presented a relatively small RMSE of about 0.27 m and no specific characteristics of bias such as the validation results at IORS. In this paper, we propose a conversion formula to correct the significant wave data of IORS with the satellite SWH data. In addition, this study emphasizes that the reliability of data should be prioritized to be extensively utilized and presents specific methods and strategies in order to upgrade the IORS as an international world-wide marine observation site.

Korean Ocean Forecasting System: Present and Future (한국의 해양예측, 오늘과 내일)

  • Kim, Young Ho;Choi, Byoung-Ju;Lee, Jun-Soo;Byun, Do-Seong;Kang, Kiryong;Kim, Young-Gyu;Cho, Yang-Ki
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.18 no.2
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    • pp.89-103
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    • 2013
  • National demands for the ocean forecasting system have been increased to support economic activity and national safety including search and rescue, maritime defense, fisheries, port management, leisure activities and marine transportation. Further, the ocean forecasting has been regarded as one of the key components to improve the weather and climate forecasting. Due to the national demands as well as improvement of the technology, the ocean forecasting systems have been established among advanced countries since late 1990. Global Ocean Data Assimilation Experiment (GODAE) significantly contributed to the achievement and world-wide spreading of ocean forecasting systems. Four stages of GODAE were summarized. Goal, vision, development history and research on ocean forecasting system of the advanced countries such as USA, France, UK, Italy, Norway, Australia, Japan, China, who operationally use the systems, were examined and compared. Strategies of the successfully established ocean forecasting systems can be summarized as follows: First, concentration of the national ability is required to establish successful operational ocean forecasting system. Second, newly developed technologies were shared with other countries and they achieved mutual and cooperative development through the international program. Third, each participating organization has devoted to its own task according to its role. In Korean society, demands on the ocean forecasting system have been also extended. Present status on development of the ocean forecasting system and long-term plan of KMA (Korea Meteorological Administration), KHOA (Korea Hydrographic and Oceanographic Administration), NFRDI (National Fisheries Research & Development Institute), ADD (Agency for Defense Development) were surveyed. From the history of the pre-established systems in other countries, the cooperation among the relevant Korean organizations is essential to establish the accurate and successful ocean forecasting system, and they can form a consortium. Through the cooperation, we can (1) set up high-quality ocean forecasting models and systems, (2) efficiently invest and distribute financial resources without duplicate investment, (3) overcome lack of manpower for the development. At present stage, it is strongly requested to concentrate national resources on developing a large-scale operational Korea Ocean Forecasting System which can produce open boundary and initial conditions for local ocean and climate forecasting models. Once the system is established, each organization can modify the system for its own specialized purpose. In addition, we can contribute to the international ocean prediction community.

Prediction of Swell-like High Waves Using Observed Data on the East Coast of Korea (관측치를 활용한 동해안 너울성 고파 예측)

  • Lee, Changhoon;Ahn, Suk Jin;Lee, Byeong Wook;Kim, Shin Woong;Kwon, Seok Jae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.26 no.3
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    • pp.149-159
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    • 2014
  • In this study, we develop an algorithm to predict swell-like high waves on the east coast of Korea using the directional wave gauge which was installed near Sokcho. Using the numerical wave model SWAN, we estimate wave data in open sea from the wave data collected by using the directional wave gauge. Then, using the wave ray method and SWAN model with the open-sea wave data as offshore boundary conditions, we predict the swell-like high waves at several major points on the east coast of Korea. We verify the prediction methods with the SWAN and wave ray methods by comparing predicted data against measured one at Wangdolcho. We can improve the prediction of the swell-like high waves in the east sea of Korea using both the real-time wave measurement system and the present prediction algorithm.

Numerical Simulation of Storm Surge and Wave due to Typhoon Kong-Rey of 2018 (2018년 태풍 콩레이에 대한 폭풍해일과 파랑 수치모의)

  • Kwon, Kab Keun;Jho, Myeong Hwan;Yoon, Sung Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.4
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    • pp.252-261
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    • 2020
  • Numerical simulations of the storm surge and waves induced by the Typhoon Kong-Rey incident on the south coast of Korea in 2018 are conducted using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the south-east coast. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the KHOA (Korea Hydrographic and Oceanographic Agency) and the KMA (Korea Meteorological Administration), and the data observed at AWAC stations of the KIOST (Korea Institute of Ocean Science and Technology). Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the JTWC (Joint Typhoon Warning Center) of the United States, and the results are compared and analyzed. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.

The Formation of Hypoxia Sediment and Benthic Foraminiferal Change in Gamak Bay, Southern Coast of Korea (가막만의 빈산소 퇴적층 형성과 저서성 유공충 군집변화 연구)

  • Lee, Yeon-Gyu;Jeong, Da-Un;Kang, So-Ra;Kim, Yong-Wan;Kim, Shin;Jung, Eun-Ho;Lee, Jung-Sick
    • Ocean and Polar Research
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    • v.34 no.1
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    • pp.53-64
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    • 2012
  • In order to understand the relationship between the formation of hypoxia sediment by eutrophication and changes in benthic foraminiferal assemblage, micropaleontological and geochemical analyses were carried out on one sediment box core (K-1) recovered in the northern Gamak Bay, which is one of the aquacultural areas in the South Sea of Korea. In this analysis, the PON content in the sediment rapidly increased, while the C/N ratio and the C/S ratio decreased since 1977. These results indicate that eutrophication commenced in 1977 in the northern Gamak Bay, and consequently, the hypoxia sediment is 20 cm thick. Ammonia beccarii-Buccella frigida assemblage occurs before the formation of hypoxia sediment. Trochammina hadai-Buccella frigida assemblage appeared in the transitional period toward hypoxia and Trochammina hadai assemblage with a low abundance and diversity is observed in the hypoxia sediment. The agglutinated species T. hadai is regarded as a bio-indicator (opportunistic species) of the organic pollution in northern Gamak Bay.

Algorithm of Predicting Swell-like Significant Waves in the East Coast of Korea (동해안 너울성 고파 예측 알고리즘)

  • Ahn, Suk Jin;Lee, Byeong Wook;Kwon, Seok Jae;Lee, Changhoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.6
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    • pp.2329-2341
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    • 2013
  • In this study, we develop an algorithm to predict swell-like significant waves in the east coast of Korea using the directional wave gauge which is installed near Sokcho. Using the numerical wave model SWAN, we estimate wave data in open sea from the wave data observed through the directional wave gauge. Then, using the wave ray method with the open-sea wave data as offshore boundary conditions, we predict the swell-like significant waves at several points in the east coast of Korea. We verify the prediction methods with the SWAN and wave ray methods by comparing numerically predicted data against either target or measured data at the observation site. We can improve the prediction of the swell-like significant waves in the east sea of Korea using both the real-time wave measurement system and the present prediction algorithm.

Numerical Investigation on the Applicability of Wave-Induced Swirl Water Chamber for Wave Power Generation in Coastal Water of Korea (파력발전을 위한 파유기 회전수류 유수실의 국내 연안 적용 가능성에 대한 수치해석적 조사)

  • Choi, Jung-Kyu;Kim, Hyoung-Tae
    • Journal of Ocean Engineering and Technology
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    • v.27 no.6
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    • pp.32-42
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    • 2013
  • In this paper, a wave-induced swirl water chamber (SWC) for breakwater and wave power generation is introduced and its applicability to wave power generation in the coastal waters of Korea is investigated. The SWC type of wave power generation is a way to drive a turbine using the unidirectional swirl flow that is induced in the back of a curtain wall of a breakwater due to incident waves. The typical wave characteristics are obtained by analyzing the annual statistical wave data from KHOA (Korea Hydrographic and Oceanographic Administration). A numerical analysis is carried out on the variations in the SWC entrance height, wave height, and different installation conditions. For the numerical analysis, a commercial code, Fluent based on FVM, is used. As the entrance height decreases, the mass flow rate through the entrance is rarely changed, whereas the magnitude of the flow velocity of the smaller entrance height is greater than the other ones, which is better for the formation of an SWC swirl flow inside and the flow kinetic energy at the entrance. In cases of installation conditions where a wall is place behind and under SWC, it has been shown that the mass flow rate through the entrance is greater than that in the open condition, and sufficient flow kinetic energy is generated in the entrance for wave power generation. However, the swirl flow kinetic energy is relatively small. Thus, in the future, it is necessary to study the swirl flow generation, which is affected by the SWC shape.

A Study on Standardization of Marine Geographical Names in Korea (우리나라 해양지명 표준화에 관한 연구 - 해양지명 명명 사례조사를 중심으로 -)

  • Lim, Young-Tae;Choi, Yun-Soo;Yoon, Ha-Su
    • Spatial Information Research
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    • v.19 no.6
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    • pp.55-65
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    • 2011
  • All of area we live in has its own geographic names. Even small size of rock under the water has its own name. They are called "marine geographic names". Marine geographic names can be classified two categories. One is a proper name; the other is an attribute name. Rocks, reefs and banks referred in the introduction, belong to the category of the attribute name. And there are certain standards to name marine geographic things. In this study, we conducted a case research with the aims to figure out how we name and use those three features that we consider dangerous factors for marine navigation. This study also focused on differences between the methods used to classify attributes of marine geographic names in the past and today. In addition, it reviewed and analyzed marine geographic names used by Korea Hydrographic and Oceanographic Administration (KHOA) on its own Nautical charts and conducted a case research on marine geographic names notified by Korean Committee on Marine Geographic Names. Based on research and analysis, this study presents future methods regarding marine geographic names standardization.

A Study on the Decision for External Water Level of a River Considering Sea Level Rise (해수면 상승을 고려한 하천 외수위 결정에 관한 연구)

  • Choo, Tai Ho;Yun, Gwan Seon;Kwon, Yong Been;Ahn, Si Hyung;Kim, Jong Gu
    • The Journal of the Korea Contents Association
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    • v.16 no.4
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    • pp.604-613
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    • 2016
  • The sea level of the Earth is rising approximately 2.0mm per year (global average value) due to thermal expansion of sea water, melting of glaciers and other causes by global warming. However, when it comes to design a river, the standard of design water level is decided by analyzing four largeness tide value and harmonic constant with observed tidal water level. Therefore, it seems the external water level needs to consider an increasing speed of the seawater level which corresponds to a design frequency. In the present study, the hourly observed tidal water level targeting 47 tidal stations operated by Korea Hydrographic and Oceanographic Administration (KHOA) from beginning of observation to 2015 per hour has been collected. The variation of monthly and yearly and increasing ratio have been performed divided 4 seas such as the Southern, East, Western, and Jeju Sea. Also, the external water level existing design for rivers nearby a coast was been reviewed. The current study could be used to figure out the cause of local seawater rise and reflect the external water level as basic data.

Typhoon Researches Using the Ieodo Ocean Research Station: Part I. Importance and Present Status of Typhoon Observation (이어도 종합해양과학기지를 활용한 태풍연구: Part I. 태풍관측의 중요성 및 현황)

  • Moon, Il-Ju;Shim, Jae-Seol;Lee, Dong Young;Lee, Jae Hak;Min, In-Ki;Lim, Kwan Chang
    • Atmosphere
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    • v.20 no.3
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    • pp.247-260
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    • 2010
  • A recent dramatic increase of natural hazards in the Korean peninsular (KP) due to typhoons have raised necessities for the accurate typhoon prediction. Ieodo ocean research station (IORS) has been constructed in June 2003 at the open ocean where typhoons pass frequently, aiming to observe typhoons before the landfall to the KP and hence to improve the prediction skill. This paper investigates the importance of measurements at the IORS in the typhoon research and forecast. Analysis of the best track data in the N. W. Pacific shows that about one typhoon passes over the IORS per year on the average and 54% of the KP-landfall typhoons during 59 years (1950-2008) passed by the IORS within the range of the 150-km radius. The data observed during the event of typhoons reveals that the IORS can provide useful information for the typhoon prediction prior to the landfall (mainland: before 8-10 hrs, Jeju Island: before 4-6 hrs), which may contribute to improving the typhoon prediction skill and conducting the disaster prevention during the landfall. Since 2003, nine typhoons have influenced the IORS by strong winds above 17m/s. Among them, the typhoon Maemi (0314) was the strongest and brought the largest damages in Korea. The various oceanic and atmospheric observation data at the IORS suggest that the Maemi (0314) has kept the strong intensity until the landfall as passing over warm ocean currents, while the Ewiniar (0603) has weakened rapidly as passing over the Yellow Sea Bottom Cold Water (YSBCW), mainly due to the storm's self-induced surface cooling. It is revealed that the IORS is located in the best place for monitering the patterns of the warm currents and the YSBCW which varies in time and space.