• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.137-140
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• 2006

황해와 동중국해의 해황 변동에 관한 연구는 현장관측을 중심으로 체계적으로 많이 수행되어 왔지만, 인공위성자료를 이용한 황해와 동중국해의 해황 변동 연구는 미비한 실정이다. 이것은 인공위성자료를 통해 얻을 수 있는 관측항목이 표층수온자료에 국한되어 있었기 때문이다. 그러나 SeaWiFS 해색위성과 같은 인공위성자료들을 이용하여 부유물 농도, 엽록소 농도 등이 원활하게 생산되고 있으며 최근 연구결과에 의해 염분과 유향성분 등도 추정 및 추출이 가능케 되었으므로 이들 인공위성자료를 이용한 황해와 동 중국해의 해황 변동에 관한 연구를 수행하게 되었다. 특히 2004 년도는 계절변동에 있어서 이상기후의 해라고 점철되고 있다. 2004년 봄철의 폭설과 일시적인 고온현상, 여름철에는 10 년만의 무더위, 겨울철에는 36년만에 가장 포근한 날씨가 지속되었다. 이러한 이상기후의 발생은 해양과 대기의 상호작용에 의해서 기인했을 것이라고 생각되어 한반도 주변 해역에서 황해와 동중국해의 해황변동이 연안 해역의 해황변동과 어떠한 연관성이 존재하고, 이러한 요인들은 2004년도에 발생한 이상기후와 어떤 상관관계를 갖는지 연구하기 위한 기초연구를 진행하였다. 2003년 12월 - 2004년 2월과 2004년 12월 - 2005년 2월에 동일한 시기에 관측된 NOAA 표층수온 분포 영상 자료들을 황해와 동중국해 해역을 중심으로 월별로 비교해보면 2003년 12월 2004년 1월에 관측된 표층수온 분포값보다 2004녀 12월 - 2005년 1월에 관측된 표층수온 분포값이 상대적으로 높은 분포 특성을 나타내고 있었다. 이와 같은 현상은 국립수산과학원의 2004년 10월과 12월의 정선관측자료에서도 나타나고 있었다. 그러나 이와는 반대로 2004년 2월에 관측된 표층수온 분포값보다 2005년 2월에 관측된 표층수온 분포값이 상대적으로 낮은 분포 특성을 나타내고 있었다. 따라서 인공위성자료를 이용한 황해의 2004년 해황 분석 결과는 이상수온 상승의 원인이 쿠로시오 해류의 변동과 관련성이 높다고 판단되며 이에 대한 지속적인 연구가 현재 진행중에 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.216-216
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• 2017

제주지역의 하천은 일정강우 이상 발생 시 하천 표층이 포화된 후 갑작스러운 유출이 발생되며, 강우에 의해 점진적으로 하천유량이 증가하는 내륙지역 하천과는 다른 유출특성을 보인다. 그러나 제주지역 하천특성에 관한 연구는 최근부터 진행되어 현재까지도 내륙지역의 하천계획의 방법을 적용되고 있다. 이 연구에서는 제주도 한천유역을 대상으로 국내에서 적용되는 설계홍수량 산정방법을 적용하여 문제점을 도출하고, 지형 및 지역특성을 분석하여 설계홍수량 산정 시 매개변수의 적용방안을 개선하였다. 홍수량 검증을 위해 보유하고 있는 현장관측 자료 중 가장 큰 첨두유량이 발생한 3개의 사상을 선정하여 비교하였다. 기존 홍수량 산정방법을 이용하여 한천유역의 유출량을 산정한 결과 78.7 ~ 317.8 cms, 14.3 ~ 37.5%의 오차율로 관측자료 대비 큰 오차를 범하는 것으로 검토되었다. 한천유역의 상류지역은 45%로 매우 급한 경사형태를 보이고, CN산정 시 경사보정을 통해 홍수량을 산정한 결과 기존의 유출특성 대비 1.47 ~ 6.45% 개선되었다. 관측자료 기반 강우-유출의 최적화 기법을 통해 산정된 도달시간을 적용하여 홍수량을 산정한 결과 4.39 ~ 16.67% 개선되었으며, 한천유역을 소유역으로 구분하여 홍수량을 산정한 결과 9.92 ~32.96% 개선된 결과가 도출되었다. 이러한 결과는 지역별 함양특성과 급한 경사 특성, 토지이용에 따른 유역특성이 적용되고, 지역별 초기손실이 반영되어 홍수유출곡선이 실제 관측자료와 유사하게 나타나는 것으로 기존방법의 경우 전체 유역에 평균값이 일괄적으로 적용되기 때문에 실제관측자료와 큰 오차를 나타내는 것으로 분석되었다.

• Journal of Information Management
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• v.43 no.3
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• pp.97-115
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• 2012

This paper derives determining factor for the management of oceanographic data in two ways. 1) The type of oceanographic observation and the raw data which were collected from marine physics, marine chemistry, marine biology, marine geology area were analyzed. 2) The services of the KODC(Korea Oceangraphic Data Center), NFRDI(National Fisheries Research & Development Institute), KHOA(Korea Hydrographic and Oceanographic Administration) were analyzed to derive metadata elements for retrieval. After analyze, the 42 deciding factor were derived in the 9 areas (general, Observer, satellites, observation instruments, observatories, space, information, projects, and observational data, data processing).

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.99-99
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• 2003

우리나라 최초의 실용급 지구관측위성인 아리랑 1호는 지난 2003년 2월 21일부로 목표로 하였던 임무운영기간 3년을 완수하였다. 아리랑 1호의 정상 임무운영에 사용되는 탑재체는 전장광학카메라, 해양관측카메라, 그리고 우주과학 탑재체이며, 2001년 8월 원인을 알 수 없는 과전류 발생으로 임무가 중단된 우주과학 탑재체를 .제외한 나머지 탑재체들은 임무 운영기간동안 정상적으로 운영되었다. 전자광학카메라는 한반도를 비롯한 전 세계를 대상으로 지리정보를 위한 영상자료를 획득하는 것이 목적이었으며, 해양관측카메라는 생물학적 해양지도 및 해양환경 관측을 위한 자료를 획득하는 것이다. 우주과학 탑재체는 고에너지 전하입자에 의한 Single Event Upset현상, 우주방사능 관측, 그리고 전자의 온도 및 밀도 측정이 주요 목표였다. 당초 목표했던 임무운영기간을 초과한 현재(2003년 7월 1일 기준)까지 우주과학 탑재체를 제외한 나머지 탑재체들은 정상적으로 운영되고 있다. 본 논문은 아리랑 1호 발사 후 약 3년 6개월간의 기간동안 수행된 탑재체 운영결과들을 정리하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.458-467
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• 2019

The purpose of this study is the suggestion of optimized parameters in OI (Optimal Interpolation) by experimental study. The observation of applying optimal interpolation is ADCP (Acoustic Doppler Current Profiler) data at the southwestern sea of Korea. FVCOM (Finite Volume Coastal Ocean Model) is used for the barotropic model. OI is to the estimation of the gain matrix by a minimum value between the background error covariance and the observation error covariance using the least square method. The scaling factor and correlation radius are very important parameters for OI. It is used to calculate the weight between observation data and model data in the model domain. The optimized parameters from the experiments were found by the Taylor diagram. Constantly each observation point requires optimizing each parameter for the best assimilation. Also, a high accuracy of numerical model means background error covariance is low and then it can decrease all of the parameters in OI. In conclusion, it is expected to have prepared the foundation for research for the selection of ocean observation points and the construction of ocean prediction systems in the future.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.524-535
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• 2021

Rapid climate change and oceanic warming have increased the variability of oceanic wave heights over the past several decades. In addition, the extreme wave heights, such as the upper 1% (or 5%) wave heights, have increased more than the heights of the normal waves. This is true for waves both in global oceans as well as in local seas. Satellite altimeters have consistently observed significant wave heights (SWHs) since 1991, and sufficient SWH data have been accumulated to investigate 100-year return period SWH values based on statistical approaches. Satellite altimeter data were used to estimate the extreme SWHs at the Ieodo Ocean Research Station (IORS) for the period from 2005 to 2016. Two representative extreme value analysis (EVA) methods, the Initial Distribution Method (IDM) and Peak over Threshold (PoT) analysis, were applied for SWH measurements from satellite altimeter data and compared with the in situ measurements observed at the IORS. The 100-year return period SWH values estimated by IDM and PoT analysis using IORS measurements were 8.17 and 14.11 m, respectively, and those using satellite altimeter data were 9.21 and 16.49 m, respectively. When compared with the maximum value, the IDM method tended to underestimate the extreme SWH. This result suggests that the extreme SWHs could be reasonably estimated by the PoT method better than by the IDM method. The superiority of the PoT method was supported by the results of the in situ measurements at the IORS, which is affected by typhoons with extreme SWH events. It was also confirmed that the stability of the extreme SWH estimated using the PoT method may decline with a decrease in the quantity of the altimeter data used. Furthermore, this study discusses potential limitations in estimating extreme SWHs using satellite altimeter data, and emphasizes the importance of SWH measurements from the IORS as reference data in the East China Sea to verify satellite altimeter data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.198-210
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• 2022

The southern strait of Jeju is a divergence point of the Tsushima Warm Current (TWC), and it is the starting point of the thermohaline circulation in the waters of the Korean Peninsula, affecting the size and frequency of marine disasters such as typhoons and tsunamis, and has a very important oceanographic impact, such as becoming a source of harmful organisms and radioactively contaminated water. Therefore, for an immediate response to these maritime disasters, real-time ocean observation is required. However, compared to other straits, in the case of southern Jeju, such wide area marine observations are insufficient. Therefore, in this study, surface current field of the southern strait of Jeju was calculated using High-Frequency radar (HF radar). the large surface current field is calculated, and post-processing and data improvement are carried out through APM (Antenna Pattern Measurement) and FOL (First Order Line), and comparative analysis is conducted using actual data. As a result, the correlation shows improvement of 0.4~0.7 and RMSE of about 1~19 cm/s. These high-frequency radar observation results will help solve domestic issues such as response to typhoons, verification of numerical models, utilization of wide area wave data, and ocean search and rescue in the future through the establishment of an open data network.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.1
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• pp.56-67
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• 1999

It is desired to use a domestically manufactured ocean data buoy for the long-term operational ocean monitoring. The ocean data buoy manufacturing technology was introduced through the research cooperation with the Qingkong University of Taiwan. The introduced ocean data buoy system was further expanded and improved for more efficient application for the marine environmental monitoring in Korea. The size of the ocean data buoy is 2.5 m in diameter, which is smaller compared to the NOAA's 3.0 m discus buoy to allow easy land transportation and ocean deployment as well. From the dynamic response test of the buoy carried out numerically, it was shown that the measurement of waves with period greater than 4 seconds is acceptable. The measurement and control system of the data buoy were improved to increase the number of measuring parameters, to reduce power consumption and to enhance better data analysis and management. Each component of the improved data buoy system was described in detail in this paper. Water quality sensors of water temperature, salinity, DO, pH and turbidity were added to the system in addition to the marine meteorological sensors of wind speed and direction, air temperature, humidity, air pressure and wave. Inmarsat satellite communication system is used for the real-time data telemetry from the buoy deployed offshore. A field performance test of the improved and domestically manufactured buoy was carried out for a month at the open sea off Pohang together with DatawelI's Wave-rider buoy to compare the wave data. The results of the test were satisfactory.

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.273-287
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• 2008

Characteristics of skin-bulk sea surface temperature (SST) differences in the Northeast Asia seas were analyzed by utilizing 845 collocated matchup data between NOAA/AVHRR data and oceanic in-situ temperature measurements for selected months from 1994 to 2003. In order to understand diurnal variation of SST within a few meters of the upper ocean, the matchup database were classified into four categories according to day-night and drifter-shipboard measurements. Temperature measurements from daytime drifters showed a good agreement with satellite MCSST (Multi-Channel Sea Surface Temperature) with an RMS error of about $0.56^{\circ}C$. Poor accuracy of SST with an rrns error of $1.12^{\circ}C$ was found in the case of daytime shipboard CTD (Conductivity, Temperature, Depth) measurements. SST differences between MCSST and in-situ measurements are caused by various errors coming from atmospheric moist effect, coastal effect, and others. Most of the remarkable errors were resulted from the diurnal variation of vertical temperature structure within a few meters as well as in-situ oceanic temperatures at different depth, about 20 cm for a satellite-tracked drifting buoy and a few meters for shipboard CTD or moored buoy. This study suggests that satellite-derived SST shows significant errors of about ${\pm}3^{\circ}C$ in some cases and therefore it should be carefully used for one's purpose on the base of in-depth understanding of skin-bulk SST difference and vertical temperature structure in regional sea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.4
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• pp.145-151
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• 2006

The water line moving on the intertidal flat during a flood indicates depth contours between low and high water lines. The water lines extracted from the consecutive images are rectified to get the ground coordinates of each depth contour and integrated to provide three dimensional information of Intertidal flat topography. The tidal flat outside Saemankeum-1 sea dike shows the most obvious changes of tidal flat topography after the construction of sea dikes. This tidal flat topography was observed using digital camera images, and the calculated depths were very similar to in-situ measurement data. Topography changes obtained from two different period data were also examined.