• 한국해양공학회지
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• 제38권3호
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• pp.103-114
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• 2024

Remote sensing wave observation data are crucial when analyzing ocean waves, the main external force of coastal disasters. Nevertheless, it has limitations in accuracy when used in low-wind environments. Therefore, this study collected the raw data from MIROS Wave and Current Radar (MWR) and wave radar at the Ieodo Ocean Research Station (IORS) and applied the optimal filter by combining filters provided by MIROS software. The data were validated by a comparison with South Jeju ocean buoy data. The results showed it maintained accuracy for significant wave height, but errors were observed in significant wave periods and extreme waves. Hence, this study used an artificial neural network (ANN) to improve these errors. The ANN was generalized by separating the data into training and test datasets through stratified sampling, and the optimal model structure was derived by adjusting the hyperparameters. The application of ANN effectively improved the accuracy in significant wave periods and high wave conditions. Consequently, this study reproduced past wave data by enhancing the reliability of the MWR, contributing to understanding wave generation and propagation in storm conditions, and improving the accuracy of wave prediction. On the other hand, errors persisted under high wave conditions because of wave shadow effects, necessitating more data collection and future research.

• 한국대기환경학회지
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• 제24권5호
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• pp.501-511
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• 2008

The Objective of this study is to examine the characteristic of fine aerosol $(PM_{2.5})$ obtained at Ieodo Ocean Research Station, which lies between the eastern part of China and the south western part of Korea. The average mass concentration of $PM_{2.5}$ was $21.5{\pm}17.0{\mu}g/m^3$ during June $2004{\sim}June 2006$. The concentration was the highest in winter $(34.8{\mu}g/m^3)$ and lowest in summer $(16.5{\mu}g/m^3)$. Water soluble ions were measured for samples collected from December 2004 to September 2005. Among them, $SO_4^{2-}\;and\;NH_4^+$ were the most abundant species and accounted for 32.2% and 14.2% of the $PM_{2.5}$ mass, respectively. The mass fraction of $SO_4^{2-}$ was higher in winter (42%) than in spring (26%). Nitrate concentrations were much lower than those of sulfate due mainly to evaporation during sampling period. The cluster analysis of backward airmass trajectories showed that the high mass loadings $(26.9{\mu}g/m^3\;on\;average)$ were associated with air originating inland China. Also, the seasonal variation of $PM_{2.5}$ mass was well correlated with the frequency of westerly winds passing through the western part of China. During the ABC-EAREX2005 (March 2005), $PM_{2.5}$ mass and major ionic concentrations were higher at Ieodo, compared with $PM_{2.5}$ measurements at Gosan while they were similar in variation pattern. These results suggested that $PM_{2.5}$ mass and its ionic composition of Ieodo Ocean Research Station were greatly influenced by continental outflows from China.

• 한국해양환경ㆍ에너지학회지
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• 제9권4호
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• pp.225-234
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• 2006

이어도 종합해양과학기지에 설치된 해양환경모니터링시스템을 이용하여 얻은 수온과 염분 자료를 이용하여 이어도 기지주변의 해수 특성과 양자강에서 유출되는 저염분수의 특징, 태풍에 의한 해수 성질 변화를 파악하였다. 수온은 정확도가 매우 높은 반면, 염분자료의 정확도와 안정도는 비교적 낮았다. 여름철 표층에서 강하게 나타나는 수온과 염분의 일변화는 태양일사량의 변화 이외에도 조석에 의한 수층의 수직운동에 의해서 발생하였다. 계절변화는 수온자료에서만 발견되었다. 염분의 가장 큰 변화 원인은 양자강에서 유입되는 담수로 약 $3{\sim}4$일 사이에 최대 8 psu 정도의 변화를 일으킨다. 2003년 8월과 2004년 8월 제주도 남서부 해역에서 저염분수가 발견되기 약 10일 전에 이어도 기지에서도 저염분수가 관측되었으나, 2005년 7월에는 이어도 기지에서만 저염분수가 관측되었다. 즉, 이어도 기지를 통과한 저염분수가 반드시 제주도 근해까지 확장하지는 않는다. 2003년 9월과 2004년 8월에 강력한 태풍이 이어도 기지 근처를 지나갔는데, 태풍에 의한 영향은 약 $3{\sim}4$일 간 지속되었다.

• Animal Systematics, Evolution and Diversity
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• 제35권4호
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• pp.200-203
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• 2019

A new marine sponges, Mycale (Carmia) ieoensis n. sp., of the family Mycalidae was collected SCUBA diving in June 2017 from Ieodo Ocean Research Station, Korea. M. (C.) ieoensis n. sp. is encrusting to irregular massive type, yellow in life. This new species is similar to M. nullarosette Hoshino, 1981 in color and growth form but it differs in spicule size and sigma shape. Spicule size of M. (C.) ieoensis n. sp. smaller than that M. nullarosette. Also, M. (C.) ieoensis n. sp. has two size toxa, but M. nullarosette is not. The new species are compared to other Mycale species from the Korean region, and similar species from elsewhere.

• 한국해안해양공학회지
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• 제18권1호
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• pp.53-62
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• 2006

이어도해양과학기지에 설치된 구조물 모니터링용 가속도계, 변형률계, 경사도계에서 계측한 동적신호를 분석하였다. 가속도 신호의 분석에서는 구조적 거동에 중요한 의미를 갖는 고유진동수를 도출할 수 있었으며 수치해석에서 얻은 고유진동수와 비교하였다. 변형률신호와 경사도신호도 함께 분석하여 동적응답의 현황도 파악하였다. 서로 다른 시점의 다양한 파고가 동특성에 미치는 영향도 분석하였다. 본 연구에서 축적한 이어도해양과학기지의 동특성은 추후 지속적인 모니터링을 통해 얻게 될 동특성과의 비교를 통해 구조물의 건전성과 노후도 및 손상정도를 파악하는데 이용될 수 있을 것이다.

• 한국대기환경학회지
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• 제29권6호
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• pp.701-712
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• 2013

The purpose of this study is to determine concentrations and compositions of $PM_{2.5}$ and their characteristic variations at Ieodo Ocean Research Station in the East China Sea and to examine the influence of air pollutants transported from Asia continents. $O_3$ and meteorological parameters were measured since June 2003 and $PM_{2.5}$ filter samples were collected from June 2004 to June 2008. In total, 244 samples were analyzed for water soluble ions and carbonaceous compounds. The mean mass concentration of $PM_{2.5}$ and $O_3$ were $21.8{\pm}14.9{\mu}g/m^3$ and $51.6{\pm}16.1$ ppb, respectively. The average concentrations (mass fractions) of sulfate and ammonium were $6.26{\mu}g/m^3$ (28.74%) and $1.59{\mu}g/m^3$ (7.31%), respectively. Nitrate was considered to be lost through evaporation due to long stay at the station. The mean concentrations of EC and OC were $1.01{\mu}g/m^3$ and $2.34{\mu}g/m^3$, respectively, from June 2006 to June 2008. The average OC/EC ratio was 2.31. The organic matter converted from OC by multiplying 2.1 and elemental carbon constituted 22.60% and 4.66% of $PM_{2.5}$ mass, respectively.

• Ocean and Polar Research
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• 제26권2호
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• pp.145-154
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• 2004

Surface energy and $CO_2$ fluxes have been measured over an ocean at Ieodo Ocean Research Station of KORDI since May 2003. Eddy covariance technique, which is a direct flux measurement, is used to quantitatively understand the interaction between the ocean surface and the atmospheric boundary layer. Although fluxes were continuously measured during the period from May 2003 to February 2004, the quality control of these data yielded <20% of data retrieval. The atmospheric stability did not show any distinct dirunal patterns and remained near-neutral to stable from May to June but mostly unstable during fall and winter in 2003. Sensible heat flux showed a good correlation with the difference between the sea water temperature and the air temperature. The maximum fluxes of sensible heat and latent heat were $120Wm^{-2}$ and $350Wm^{-2}$ respectively, with an averaged Bowen ratio of 0.2. The ocean around the tower absorbed $CO_2$ from the atmosphere and the uptake rates showed seasonal variations. Based our preliminary results, the daytime $CO_2$ flux was steady with an average of $-0.1 mgCO_2m^{-2}s^{-1}$ in summer and increased in winter. The nighttime $CO_2$ uptake was greater and fluctuating, reaching up to $-0.1 mgCO_2m^{-2}s^{-1}$ but these data require further examination due to weak turbulent mixing at nighttime. The magnitude of $CO_2$ flux was positively correlated with the half hourly changes in horizontal mean wind speed. Due to the paucity of quality data, further data collection is needed for more detailed analyses and interpretation.

• Ocean and Polar Research
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• 제30권1호
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• pp.47-58
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• 2008

Several validation studies have been made for QuikSCAT(QSCAT) wind data around the world, mainly in the offshore. However, until now, there were no validation studies for QSCAT wind with resolution of 12.5 km ('QSCAT 12.5 km wind') in the vicinity of Korean Peninsula. To validate 'QSCAT 12.5 km wind' and to investigate its characteristics around Korean Peninsula, the wind data from Ieodo Ocean Research Station, KMA buoys, and KORDI Realtime Observation Stations have been compared. Validation results showed that 'QSCAT 12.5 km wind' RMSE of wind direction and speed were $25.85^{\circ}$ and 1.83 m/s, respectively, at Ieodo Station. The mean wind speed correlation coefficient of KMA buoys and KORDI Realtime Observation Station were 0.78 and 0.61, and the mean wind speed RMSE were 2.2 m/s and 3.2 m/s, respectively. This seems to be mainly because of the distance between QSCAT and in-situ observation stations. The RMSE of wind direction were bigger than $40^{\circ}$ at all in-situ observation stations located near the shore, within 20 km from coastlines. Geophysical features where in-situ observation stations are located seem to affect wind validation scores.

• 한국해안해양공학회지
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• 제19권5호
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• pp.476-483
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• 2007

이어도에 건설된 다목적 해양과학기지에서는 주위 대류 및 해류의 데이터 수집을 통해 기상, 어장예보 등의 기초 자료를 제공하는 것을 한 가지 목적으로 한다. 그런데 이어도 기지 구조물에 의한 해수 유동의 변화는 과학기지의 관측 데이터에 영향을 주어 정확한 자료 수집을 어렵게 하므로, 이어도 기지 구조물이 주위 유동에 미치는 영향을 분석하고 유동 정보 관측을 평가/보정하는 방법에 대한 연구가 필요하다. 본 연구에서는 이를 위한 기초연구로, 해류와 구조물 사이의 상호 작용을 모사 할 수 있는 알고리즘을 연구, 적용방법을 논의한다. 그 결과, 3차원 전산유체역학을 이용한 수치해석을 통해 이어도 기지 구조물 및 수중암초가 주위 유동에 미치는 영향을 연구하고 정확한 데이터 측정방법을 제안한다.

• 한국지구과학회지
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• 제41권4호
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• pp.323-343
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• 2020

Observation data measured at Ieodo Ocean Research Station (IORS) have been utilized in oceanographic and atmospheric studies since 2003. Sea level data observed at the IORS have not been paid attention as compared with many other variables such as aerosol, radiation, turbulent flux, wind, wave, fog, temperature, and salinity. Total sea level rises at the IORS (5.6 mm yr^-1) from both satellite and tide-gauge observations were higher than those in the northeast Asian marginal seas (5.4 mm yr^-1) and the world (4.6 mm yr^-1) from satellite observation from 2009 to 2018. The rates of thermosteric, halosteric, and steric sea level rises were 2.7-4.8, -0.7-2.6, 2.3-7.4 mm yr^-1 from four different calculating methods using observations. The rising rate of the steric sea level was higher than that of the total sea level in the case with additional data quality control. Calculating the non-steric sea level was not found to yield meaningful results, despite the ability to calculate non-steric sea level by simply subtracting the steric sea level from total sea level. This uncertainty did not arise from the data analysis but from a lack of good data, even though tide, temperature, and salinity data were quality controlled two times by Korea Hydrographic and Oceanography Agency. The status of the IORS data suggests that the maintenance management of observation systems, equipment, and data quality control should be improved to facilitate data use from the IORS.