• 한국측량학회지
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• 제36권5호
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• pp.343-353
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• 2018

Ocean tides in Antarctica are not well constrained mostly due to the lack of tidal observations. Especially, tides underneath and around ice shelves are uncertain. InSAR (Interferometric Synthetic Aperture Radar) data has been used to observe ice shelf movements primarily caused by ocean tides. Here, we demonstrate that it is possible to estimate tidal constituents underneath the Sulzberger ice shelf, West Antarctica, solely using ERS-1/2 tandem mission DInSAR (differential InSAR) observations. In addition, the tidal constituents can be estimated in a high-resolution (~200 m) grid which is beyond any tidal model resolution. We assume that InSAR observed ocean tidal heights can be derived after correcting the InSAR data for the effect of atmospheric loading using the inverse barometric effect, solid earth tides, and ocean tide loading. The ERS (European Remote Sensing) tandem orbit configuration of a 1-day separation between SAR data takes diminishes the sensitivity to major tidal constituents including $K_1$ and $S_2$. Here, the dominant tidal constituent $O_1$ is estimated using 8 differential interferograms underneath the Sulzberger ice shelf. The resulting tidal constituent is compared with a contemporary regional tide model (CATS2008a) and a global tide model (TPXO7.1). The InSAR estimated tidal amplitude agrees well with both models with RMS (root-mean-square) differences of < 2.2 cm and the phase estimate corroborating both tide models to within $8^{\circ}$. We conclude that fine spatial scale (~200 m) Antarctic ice shelf ocean tide determination is feasible for dominant constituents using C-band ERS-1/2 tandem mission InSAR.

• International Journal of Contents
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• 제18권1호
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• pp.76-84
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• 2022

Tidal power generation plays a critical role in reducing greenhouse gas emissions. It uses a tidal force generated by gravitational force between the moon, the earth, and the sun. The change of seawater height generates the tide-generating force, and the magnitude of the change is the tide level. The tide level change has the same period as the tide-generating force twice a day, every 29.5 days, every year, and every 18.6 years. Sihwa Lake Tidal Power Station is Korea's first tidal power plant that began commercial power generation in August 2011 and has been accumulating a large volume of data on electricity production, power generation sales, sluice displacement, and tide levels. The purpose of this paper was to analyze the impact of the inefficiency factors affecting production and the tidal level change on tidal power generation and their characteristics using Sihwa Lake Tidal Power's operational performance data. Throughout this paper we show that tidal power generating operation is accurately predicting the trends of magnitude of tidal force to be periodical for each day. determining the drop to initiate the water turbine generator factoring the constraints on the operation of Sihwa Lake, and reflecting the water discharge through the floodgate and water turbine during the standby mode in the power generation plan to be in the optimal condition until the initiation of the next power generation can maximize power generation.

• 한국지구과학회지
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• 제27권1호
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• pp.6-14
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• 2006

본 연구에서는 중학교 과학 영재아들이 가지고 있는 조석에 관한 정신모형을 탐색하기 위하여 두 가지 상황에서의 개념 유형을 분류하고, 각 유형들을 구성하는 국면들을 분석하였다. 조석 현상에 관해 두 가지 상황으로 구성된 과제 수행을 실시한 후 그 응답 결과를 분석한 결과, 상당수의 학생들이 상황에 따라 서로 다른 개념 유형을 나타내었다. 상황에 따른 개념 유형들을 구성하고 있는 국면을 분석한 결과, 내용-특정적 국면에서는 큰 차이가 없었으나 전략적 국면에서는 많은 차이를 나타내었다. 두 가지 상황에서 나타나는 개념 유형들과 이들 유형을 구성하는 국면들을 조합하여 학생들의 조석에 관한 정신모형을 분석한 결과 다음과 같은 4가지 모형으로 나눌 수 있었다: (1) Tide model (2) Force model (3) Phase model (4) Hybrid model. Tide model은 과학적으로 옳은 모형이며, Force model과 Phase model은 옳지 않은 모형으로, 상황에 따른 개념유형은 서로 일치하나 조석현상을 각각 달과 태양의 합력과 달의 위상(모양)의 관계로만 이해하고 있는 경우이다. Hybrid model 혼합 모형으로 상황에 따라 나타나는 개념 유형이 서로 부합되지 않는 모형이다. 중학교 과학 영재아들은 조석 현상에 대해 가장 많이 가지고 있는 모형은 Tide model(45.0%) 이었으며, 그 다음으로는 Hybrid model(30.0%), Force model(12.5%), Phase model(7.5%) 순으로 나타났다.

• 천문학회지
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• 제47권1호
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• pp.41-41
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• 2014

The equivalent phase lag ${\varepsilon}_{lmpq}$ of Earth tide suggested by Lambeck have been found reasonable. Due to a mistake in his calculation, the author falsely claimed that those are too large. However, the main contents of the article are valid and not affected by this mistake.

• Ocean Science Journal
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• 제40권4호
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• pp.191-200
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• 2005

In this study an analytical tide model of uniform width with three sub-regions is presented. The three-subregions model takes into account step-like variations in depths in the direction of the channel as a way to examine the $M_2$ tide of the East China Sea (ECS) as well as the Yellow Sea (YS). A modified Proudman radiation condition has been applied at the northern open head, while the sea surface elevation is specified at the southern open boundary. It is seen that, due to the presence of an abrupt change in depth, co-amplitude lines of the $M_2$ tide are splitted to the east and west near the end of the ECS shelf region. Variations in depths, bottom friction and the open head boundary conditions all contribute to the determination of formation of amphidromes as well as overall patterns of $M_2$ tidal distribution. It is seen that increasing water depth and bottom friction in the ECS shelf results in the westward shift of the southern amphidrome. There is however no hint at all of the well-known degenerated tidal pattern being formed. It is inferred that a lateral variation of water depth has to be somehow incorporated to represent the tidal patterns in ECS in a realistic manner. Regarding the radiation factor introduced by Fang et al. (1991), use of a value larger than one, possibly with a phase shift, appears to be a proper way of incorporating the reflected waves from the northern Yellow Sea (NYS).

• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2005년도 추계학술발표회 논문집
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• pp.254-262
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• 2005

본 연구에서는 중학교 과학 영재아들이 가지고 있는 조석에 관한 정신모형을 탐색하기 위하여 상황에 따른 개념 유형을 분류하고, 각 유형들을 구성하는 국면들을 분석하였다. 조석 현상에 관해 두 가지 상황으로 구성된 과제 수행을 실시한 후 그 응답 결과를 분석한 결과, 상당수의 학생들이 상황에 따라 서로 다른 개념 유형을 나타내었다. 상황에 따른 개념 유형들을 구성하고 있는 국면을 분석한 결과, 각 유형들은 내용-일반적 국면을 공통적으로 포함하고 있었으나, 내용-특정적 국면과 전략적 국면에서는 많은 차이를 나타내었다. 두 가지 상황에서 나타나는 개념 유형들과 이들 유형을 구성하는 국면들을 조합하여 학생들의 정신모형을 분석한 결과 다음과 같은 4가지 모형으로 나눌 수 있었다: (1) Tide model (2) Force model (3) Phase model (4) Hybrid model. Tide model은 과학적으로 옳은 모형이며, Force model과 Phase model은 옳지 않은 모형이며, Hybrid model은 혼합 모형으로 상황에 따라 나타나는 개념 유형이 서로 부합되지 않는 모형이다. 중학교 과학 영재아들이 조석 현상에 대해 가장 많이 가지고 있는 모형은 Tide model(45.0%)이었으며, 그 다음으로는 Hybrid model(30.0%), Force model(12.5%), Phase model(7.5%) 순으로 나타났다.

• 한국전자통신학회논문지
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• 제11권7호
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• pp.723-728
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• 2016

본 연구에서는 Landsat-7 ETM+, Landsat-8 OLI 영상과 COMS/GOCI 영상을 이용하여 적조 픽셀의 광학적 특성을 분석하였다. 적조 픽셀을 샘플링하기 위해 Landsat-7, 8 True Color 영상을 활용하였으며, 영상에서 적조 픽셀의 좌표를 획득하였다. 획득된 픽셀의 좌표를 참조하여 동일 해역의 GOCI 영상을 통해 해당픽셀의 흡광 및 수출광량 자료를 획득하였다. 적조가 발생하지 않은 경우 412nm와 660nm 파장대에서 주흡광을 보인 것에 비해 적조 픽셀의 경우 660nm에서 주흡광을 보였으며, 412nm에서는 흡광량이 현저히 줄어든 것을 확인하였다. 수출광량의 경우 스펙트럼 형태에서는 큰 차이가 없었으나, 수출광량의 절대값이 적조 픽셀의 경우 낮게 나타났으며, 특히 660nm와 680nm 파장대에서 수출광량 감소가 크게 나타났다.

• Journal of the korean society of oceanography
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• 제39권2호
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• pp.119-135
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• 2004

A three-dimensional numerical model using POM (the Princeton Ocean Model) is established in order to understand the dispersion processes of the Yangtze River water in the Yellow and East China Seas. The circulation experiments for the seas are conducted first, and then on the bases of the results the dispersion experiments for the river water are executed. For the experiments, we focus on the tide effects and wind effects on the processes. Four cases of systematic experiments are conducted. They comprise the followings: a reference case with no tide and no wind, of tide only, of wind only, and of both tide and wind. Throughout this study, monthly mean values are used for the Kuroshio Current input in the southern boundary of the model domain, for the transport through the Korea Strait, for the river discharge, for the sea surface wind, and for the heat exchange rate across the air-sea interface. From the experiments, we obtained the following results. The circulation of the seas in winter is dependent on the very strong monsoon wind as several previous studies reported. The wintertime dispersion of the Yangtze River water follows the circulation pattern flowing southward along the east coast of China due to the strong monsoon wind. Some observed salinity distributions support these calculation results. In summertime, generally, low-salinity water from the river tends to spread southward and eastward as a result of energetic vertical mixing processes due to the strong tidal current, and to spread more eastward due to the southerly wind. The tide effect for the circulation and dispersion of the river water near the river mouth is a dominant factor, but the southerly wind is still also a considerable factor. Due to both effects, two major flow directions appear near the river mouth. One of them is a northern branch flow in the northeast area of the river mouth moving eastward mainly due to the weakened southerly wind. The other is a southern branch flow directed toward the southeastern area off the river mouth mostly caused by tide and wind effects. In this case, however, the tide effect is more dominant than the wind effect. The distribution of the low salinity water follows the circulation pattern fairly well.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.312-316
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• 2002

Satellite radar interferometry data shows a strong coherent signal on oyster sea farms where artificial structures installed on the bottom. We obtained 21 highly coherent interferograms from eleven JERS-1 SAR data sets despite of large orbital baseline (~2 km) or large temporal baseline (~l year). The phases observed in sea farms are probably induced by double bouncing on sea surface, and consequently reveal a tide height variation. To restore the absolute sea level changes we counted the number of wrapping by exploiting the intensity of backscattering. Backscattering intensity is closely correlated with the change in water surface height, while interferometry gives the detailed variation within the limit of 2$\pi$ (or 15.3 cm). Comparing the radar measurements with the tide gauge records yielded a correlation coefficient of 0.96 and an ms error of 6.0 cm. The results demostrate that radar interferometry is promising to measure sea level.

• 대기
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• 제27권4호
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• pp.399-409
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• 2017

The impact of land cover changed by tidal flats on local meteorology in Gyeonggi Bay was quantitatively evaluated based on a numerical modeling approach during 18 days (21 June to 9 July 2013). The analysis was carried out using three sets of simulation scenarios and the land cover of tidal flats for each simulation was applied as follows: (1) the herbaceous wetland representing coastal wetlands (i.e., EXP-BASE case), (2) the barren or sparsely vegetated representing low tide (i.e., EXP-LOW case), (3) the water bodies representing high tide (i.e., EXP-HIGH case). The area of tidal flats was calculated as about $552km^2$ (the ratio of 4.7% for analysis domain). During the daytime, the change (e.g. wetlands to water) of land cover flooded by high tide indicated the decrease of temperature (average $3.3^{\circ}C$) and the increase of humidity (average 13%) and wind speed (maximum $2.9m\;s^{-1}$). The changes (e.g. wetlands to barren or sparsely vegetated) of land cover induced by low tide were smaller than those by high tide. On the other hands, the effects of changed land cover at night were not apparent both high tide and low tide. Also, during the high tide, the meteorological change in tidal flats affected the metropolitan area (about 40 km from the tidal flat).