• Journal of the Korean earth science society
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• v.23 no.4
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• pp.349-356
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• 2002

In an effort to properly assess the validity of spaceborne radar altimeter measurements, we made a direct comparison of two different sea surface heights (SSH) acquired by both Topex/Poseidon (T/P) satellite and in-situ tide-gauges (T/G). This comparative analysis was conducted using the data sets collected from three locations along the eastern coast of Korea which include: Ulleungdo, Pohang, and Sokcho. In the course of the analysis of satellite altimeter, information of SSH was extracted from the T/P MGDR data sets through the application of both atmospheric and geophysical corrections. To compare the T/P data sets in parallel basis, the T/G data sets were averaged using the measured values within the peripheral radius of 55km. When compared among different locations, the compatibility between the two methods was much more significant in an offshore location (Ulleungdo) than the two onshore locations (Pohang, Sokcho). If the low-pass filtered results were compared among the sites, the offshore site exhibited the best correlations between the two methods (correlation coefficient of 0.91) than those of the onshore sites. These large differences in the strength of correlations among different locations are due to the deformation of M2, S2, and K1 tidal components used in the tidal model. In case of the offshore location, the compatibility of the two different methods were improved systematically by the low-pass filtering with an increase of the filtering duration such as up to 200 days.

• Journal of the Korean association of regional geographers
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• v.4 no.2
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• pp.151-164
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• 1998

I analyzed the correlation between El-Nino phenomenon and our country's temperature and precipitation laying the stress on the anomaly, and the result of this analysis is as follows: (1) The extraction of the occurrences of El-Nino at the place of sea surface around Nino.3 which was known as the sea area under observation for El-Nino reveals that there are 9 years (1969, 1970, 1973, 1977, 1987, 1992, 1995, 1998) when the temperature anomaly in January is more than 1.0 during the period of research years ($1969{\sim}1998$). (2) The tendency of change of sea surface temperature around Nino.3 and that of our country are about the same, but the anomaly of Pusan and Inchon was much greater than that of Jangki in the East Coast. (3) The anomaly of sea surface temperature around Nino.3 and that of the ground temperature showed the similar changing tendency, the temperature of our country has something to do with that of sea surface as the correlation of ground temperature with the temperature of sea surface showed 0.31. Anomaly warm winter has something to do with El-Nino because the temperature of our country was high when El-Nino phenomenon appeared. (4) As for the precipitation, we can see that it has generally increased after 1989 when the phenomenon of warm climate was intense than before that year. But as we study the change of anomaly, the precipitation has less correlation in comparison with the ground temperature. The precipitation in 1973, 1983 and 1987 which were El-Nino years was correlated with El-Nino. While the change of sea surface temperature has showed a tendency of plus(+)increase since 1990, the precipitation has showed a tendency of minus (-)decrease. Therefore it seems that the temperature of sea surface has little correlation with the amount of rainfall.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.128-132
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• 2010

울릉분지 북동쪽 독도 주변 해역은 해수면 위의 작은 섬들과 해저에 큰 화산체로 구성된 독도와 해수면 아래 큰 규모의 해산 두 개(심흥택해산, 이사부해산)가 위치하고 있으며 그 중 해수면위로는 독도만 솟아 있다. 정밀해저면영상기(MS-1000)를 이용하여 큰 규모의 조사선으로 접근이 어려웠던 동도-서도 주변 연안에 대한 정밀해저면영상 조사를 2010년 1월에 소형조사선을 이용하여 수행하였다. 부두 동쪽 해안은 동도와 근접하고 있어 큰 규모의 돌출 암반이 많이 분포하고 있으며 부두 북쪽으로는 모래층의 연흔구조가 많이 나타나며 소규모의 암반 및 자갈들이 많이 분포하는 것으로 판단된다. 동도와 서도사이의 해저면영상을 분석해보면 동도 선착장부근으로는 모래퇴적물의 연흔구조가 많이 나타나고 동도와 서도 중앙부로 가면서 모래보다는 작은 자갈들이 많이 분포하며 서도쪽으로 가면서는 모래 및 자갈퇴적물이 암반구조로 이루어져있는 것으로 판단된다. 정밀해저면영상기(MS-1000)는 고정밀한 해저면영상을 획득할 수 있으며 불규칙한 지형으로 기존 장비가 접근하없어지며기 어려운 해저지형에도 사용하기 적합한 것으로 판단된다. 향후 항구 및 해안구조물 등과 같은 고정밀해저면영상이 필요한 분야에 활용성이 높을 것으로 생각되고 또한 유지/보수가 필요한 수중 군시설 및 부두시설에 대한 정밀조사를 통하여 효율적 관리 정보제공할 수 있을 것으로 판단된다.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.613-623
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• 2019

Over the past decades, daily sea surface temperature (SST) composite data have been produced using periodically and extensively observed satellite SST data, and have been used for a variety of purposes, including climate change monitoring and oceanic and atmospheric forecasting. In this study, we evaluated the accuracy and analyzed the error characteristic of the SST composite data in the sea around the Korean Peninsula for optimal utilization in the regional seas. We evaluated the four types of multi-satellite SST composite data including OSTIA (Operational Sea Surface Temperature and Sea Ice Analysis), OISST (Optimum Interpolation Sea Surface Temperature), CMC (Canadian Meteorological Centre) SST, and MURSST (Multi-scale Ultra-high Resolution Sea Surface Temperature) collected from January 2016 to December 2016 by using in-situ temperature data measured from the Ieodo Ocean Research Station (IORS). Each SST composite data showed biases of the minimum of 0.12℃ (OISST) and the maximum of 0.55℃ (MURSST) and root mean square errors (RMSE) of the minimum of 0.77℃ (CMC SST) and the maximum of 0.96℃ (MURSST) for the in-situ temperature measurements from the IORS. Inter-comparison between the SST composite fields exhibited biases of -0.38-0.38℃ and RMSE of 0.55-0.82℃. The OSTIA and CMC SST data showed the smallest error while the OISST and MURSST data showed the most obvious error. The results of comparing time series by extracting the SST data at the closest point to the IORS showed that there was an apparent seasonal variation not only in the in-situ temperature from the IORS but also in all the SST composite data. In spring, however, SST composite data tended to be overestimated compared to the in-situ temperature observed from the IORS.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.268-268
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• 2019

이상기후 등 전 지구적 기후 변화로 인하여 해수면 상승과 태풍에 의한 해일고 증가로 인하여 해안지역의 침수 재해 발생빈도가 증가되고 있다. 우리나라도 지난 2002년 발생한 태풍 '루사' 와 2003년 발생한 태풍 '매미' 뿐만 아니라 2016년 태풍 '차바'로 인해 부산 및 울산 등 남부 해안지역 침수되는 등 막대한 재산과 인명피해 발생 빈도가 증가하고 있는 실정이다. 따라서 본 연구에서는 해수면 상승 또는 해일로 인하여 해안도시가 침수되는 현상을 모의하기 위하여 천수방정식을 지배방정식으로 하고 유한체적법과 well-balanced 기법이 적용된 2차원 수치모형을 개발하여 침수 모의 결과에 대한 적절성을 검토하였다. 또한 개발된 모형을 이용하여 해수침수 저감을 위한 월파 방지벽의 설치효과를 수문학적/경제학적으로 분석하여 최적의 대안을 제안하고자 하였다. 모의결과의 검증을 위해서 2003년 발생한 태풍 '매미'로 인하여 침수가 발생한 창원시의 침수흔적과 모의결과를 비교검토하였다. 또한 해수면 상승에 대한 방어적 기법으로 월파방지벽을 선정하고 다양한 월파방지벽의 높이에 따른 시공적 침수규모에 대한 분석과 함께 피해액과 시공비를 고려한 경제성 분석을 통하여 최적의 월파방지벽 규모와 그 효과를 분석하였다. 본 연구결과는 지점별 침수규모 및 최대 침수심 발생시간을 제공함으로써 침수에 따른 중장기적 구조적 대응방안 수립은 물론 초단기적 예상 해수면 상승에 따른 대피경로의 효율적 운용 등 비구조적 수재해 대응 기법을 제시하는 기초자료 제공에 활용할 수 있을 것으로 기대된다.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.467-479
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• 2023

Satellite altimeters have continuously observed sea surface height (SSH) in the global ocean for the past 30 years, providing clear evidence of the rise in global mean sea level based on observational data. Accurate altimeter-observed SSH is essential to study the spatial and temporal variability of SSH in regional seas. In this study, we used measurements from the Ieodo Ocean Research Station (IORS) and validate SSHs observed by satellite altimeters (Envisat, Jason-1, Jason-2, SARAL, Jason-3, and Sentinel-3A/B). Bias and root mean square error of SSH for each satellite ranged from 1.58 to 4.69 cm and 6.33 to 9.67 cm, respectively. As the matchup distance between satellite ground tracks and the IORS increased, the error of satellite SSHs significantly amplified. In order to validate the correction of the tide and atmospheric effect of the satellite data, the tide was estimated using harmonic analysis, and inverse barometer effect was calculated using atmospheric pressure data at the IORS. To achieve accurate tidal corrections for satellite SSH data in the seas around the Korean Peninsula, it was confirmed that improving the accuracy of tide data used in satellites is necessary.

• The Journal of Engineering Geology
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• v.13 no.1
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• pp.17-27
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• 2003

In this study, a phenomenon of saltwater intrusion was monitored under various conditions regarding recharge and pumping rate using time domain reflectometry for a laboratory scale unconfined aquifer to verify the basic theory behind seawater intrusion and to investigate movement of salt-freshwater interface in accordance with the ratio of pumping and recharge rate. Results showed that a thick mixing zone was formed at the boundary instead of a sharp salt-freshwater interface that was assumed by Ghyben and Herzberg who derived an equation relating the water table depth $(H_f)$ to the depth to the interface $(H_s)$. Therefore our experimental results did not agree with the calculated values obtained from the Ghyben and Herzberg equation. Position of interface which was adopted as 0.5 g/L isochlor moved rapidly as the Pumping rate $(Q_p)$ increased for a given recharge rate $(Q_r)$. In addition, interface movement was found to be about 7 times the ratio of $Q_p/Q_r$ in our experimental condition. This indicates that Pumping rate becomes an important factor controlling the seawater intrusion in coastal aquifer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.4
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• pp.227-234
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• 2007

The present study attempts to provide basic directions to respond to sea-level rise effectively based on the status of sea-level rise and its impact. The impact of the sea-level rise will be one of the most adverse component among climate change due to global warming. The basic approach to deal with sea level rise requires both mitigation and adaptation. Though the emission reduction can reduce a portion of sea level rise, the rising trend cannot be avoided due to the difficulty of the emission reduction and a strong inertia of the ocean. Therefore an effective corresponding direction has to focus on the development of appropriate adaptation strategies. Because sea level rise problem has scientific uncertainty, the corresponding system has to be designed to deal with the processes of information and awareness, planning and design, implementation, and monitoring and evaluation in continuous and long-term process. The future task to correspond effectively to the issue in Korea includes the improvement of scientific information, the development of adaptative measures, the enhancement of people awareness, the consensus of corresponding necessity, and formation of integrated corresponding system.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.235-246
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• 2011

Sea level fluctuations during the Holocene reconstructed by the results of age dating, microfossils researches and sedimentary facies from coastal alluvial plains contain the valuable informations on climatic changes. The sea level during 'maximum phase of transgression' during 6,000~5,000 yr BP was slightly higher than the present by approximately 0.8~1.0 m and the summer temperature conditions seemed to be higher than those of the present by 2~3℃ in the Central Europe when the period of 'Climatic Optimum' might be dominant. The sea level in Korean Peninsula was assumed by 0.8~1.0 m higher at that time compared to the present and climate seemed to be warmer. At 2,000~1,800 yr BP in Korean Peninsula, the sea level reached the higher stand than the present by approximately 1.1~1.3 m and the climatic conditions might be warm similar to the period of 'Climatic Optimum'. Although the temperature in the Central Europe during the period of 'Subboreal' was about 2~3℃ cooler, it is supposed that the sea level in Korean Peninsula was relatively higher than the present. The sea level at 2,300 yr BP might be similar to that of the present, which was the lowest level since the mid-Holocene. From the fact, climatic environment during the cold period might not be reflected exactly in the sea level.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.224-232
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• 2006

This study investigates to detect Sea Surface Temperature (SST) and land cover change after tide embankment construction using Landsat Thematic Mapper (TM) Thermal Infrared (TIR) band data at Shihwa Lake and surrounding area. SST measurement is important for studies of both the structure of the ocean and as the thermal boundary between the ocean and the atmosphere. Since 1970s, the derivation of SST by satellite remote sensing (RS) has been applied to earth surface using Advanced Very High Resolution Radiometer (AVHRR) and Landsat TM. However, AVHRR has restriction in deriving SST in the area whose shoreline is complicated like western coast in South Korea because of coarse spatial resolution. The TIR band of TM images can be used to detect SST change whose shoreline is complicated and narrow like the study site. Thus, multi-temporal TM images were used for SST change detection in this study.