• Title/Summary/Keyword: oceanic model

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A Study of Strategy Development of Marina using ubiquitous sensor network (유비쿼터스 센서네트워크 기반의 스마트 마리나 구축에 관한 연구)

  • Kang, Nam-Seon;Kwon, Youn-Won
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2011.06a
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    • pp.96-97
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    • 2011
  • In these days many korean people have much interested in oceanic sports and oceanic leisure equipment.. However, the current condition for the marine leisure in korea are not advanced even worse than wnderdeveloped countries.. Recently several suggestion for vitalization on the marine leisure industry and preparations of the laws & the regulations for marine leisure.. This paper suggest the new marina model using ubiquitous sensor network to reduce the risk of the policy and the investment in the filed og marine leisure industry.

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Oil Spill Behavior forecasting Model in South-eastern Coastal Area Of Korea (한국 동남해역에서의 유출유 확산예측모델)

  • Ryu Cheong Ro;Kim Jong Kyu;Seol Dong Guan;Kang Dong Uk
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.1 no.2
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    • pp.52-59
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    • 1998
  • Many concerns are placed on preservation of coastal environment from the spilled oil contaminant in the coastal area. And the use of computer simulation model to combat with oil spill has come to play mote important role in forecasting the oil spill trajectory so as to protect coastal area and minimize the damage from oil contaminants. The main concerns of this study is how the movements of spilled oil are affected by currents including tidal, oceanic, and wind-driven currents. Especially, in the present paper, the oil spill trajectory can be predicted by a real-time system that allows prediction of circulation and wind field. The harmonic methods are adopted to simulate the tidal currents as well as it can be possible to achieve the wind-field data and oceanic current data from the established database. System performance is illustrated by the simulation of oil spill in the south-eastern coastal area of Korea. Simulation results are compared with the observed one.

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Fractals in the Spreading of Drifters: Observation and Simulation (표류부표 분산의 프랙탈 성질: 관측 및 시뮬레이션)

  • KANG, YONG Q.;LEE, MOONJIN
    • 한국해양학회지
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    • v.29 no.4
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    • pp.392-401
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    • 1994
  • We examined the temporal characteristics of the oceanic eddy diffusion at 5 coastal regions of Korea by measuring the separation distances of multiple drifters released simultaneously at the same by the GPS and Decca transponder system. The observed variance of separation distance, for the time scales from minutes to hours, is proportional to t/SUP m/ with scaling exponent m between 1.2 and 2.0. The observed Lagrangian trajectories of drifters show fractal characteristics instead of random walk or Brown motion. As an effort toward a development of a realistic model of the oceanic eddy diffusion, we simulated the Lagrangian trajectories of drifters by fractional Brown motion (FBM) model. The observed variances of drifter separations can be generated by the FBM process provided the Hurst exponent is the same as the observed one. We further showed that the observed power law in the variance of drifter separations cannot be simulated with an ordinary Brown motion or random walk process.

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Dynamically Induced Anomalies of the Japan/East Sea Surface Temperature

  • Trusenkova, Olga;Lobanov, Vyacheslav;Kaplunenko, Dmitry
    • Ocean and Polar Research
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    • v.31 no.1
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    • pp.11-29
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    • 2009
  • Variability of sea surface temperature (SST) in the Japan/East Sea (JES) was studied using complex empirical orthogonal function (CEOF) analysis. Two daily data sets were analyzed: (1) New Generation 0.05o-gridded SST from Tohoku University, Japan (July 2002-July 2006), and (2) 0.25o-gridded SST from the Japan Meteorological Agency (October 1993-November 2006). Linkages with wind stress curl were revealed using 6-h 1o-gridded surface zonal and meridional winds from ancillary data of the Sea- WiFS Project, a special National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) product (1998-2005). SST anomalies (SSTA) were obtained by removing the seasonal signal, estimated as the leading mode of the CEOF decomposition of the original SST. Leading CEOF modes of residual SSTA obtained from both data sets were consistent with each other and were characterized by annual, semiannual, and quasi-biennial time scales estimated with 95% statistical significance. The Semiannual Mode lagged 2 months behind the increased occurrence of the anticyclonic (AC) wind stress curl over the JES. Links to dynamic processes were investigated by numerical simulations using an oceanic model. The suggested dynamic forcings of SSTA are the inflow of subtropical water into the JES through the Korea Strait, divergence in the surface layer induced by Ekman suction, meridional shifts of the Subarctic Front in the western JES, AC eddy formation, and wind-driven strengthening/weakening of large-scale currents. Events of west-east SSTA movement were identified in July-September. The SSTA moved from the northeastern JES towards the continental coast along the path of the westward branch of the Tsushima Current at a speed consistent with the advective scale.

Errors in Estimated Temporal Tracer Trends Due to Changes in the Historical Observation Network: A Case Study of Oxygen Trends in the Southern Ocean

  • Min, Dong-Ha;Keller, Klaus
    • Ocean and Polar Research
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    • v.27 no.2
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    • pp.189-195
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    • 2005
  • Several models predict large and potentially abrupt ocean circulation changes due to anthropogenic greenhouse-gas emissions. These circulation changes drive-in the models-considerable oceanic oxygen trend. A sound estimate of the observed oxygen trends can hence be a powerful tool to constrain predictions of future changes in oceanic deepwater formation, heat and carbon dioxide uptake. Estimating decadal scale oxygen trends is, however, a nontrivial task and previous studies have come to contradicting conclusions. One key potential problem is that changes in the historical observation network might introduce considerable errors. Here we estimate the likely magnitude of these errors for a subset of the available observations in the Southern Ocean. We test three common data analysis methods south of Australia and focus on the decadal-scale trends between the 1970's and the 1990's. Specifically, we estimate errors due to sparsely sampled observations using a known signal (the time invariant, temporally averaged, World Ocean Atlas 2001) as a negative control. The crossover analysis and the objective analysis methods are for less prone to spatial sampling location biases than the area averaging method. Subject to numerous caveats, we find that errors due to sparse sampling for the area averaging method are on the order of several micro-moles $kg^{-1}$. for the crossover and the objective analysis method, these errors are much smaller. For the analyzed example, the biases due to changes in the spatial design of the historical observation network are relatively small compared to the tends predicted by many model simulations. This raises the possibility to use historic oxygen trends to constrain model simulations, even in sparsely sampled ocean basins.

An Oceanic Front : The Formation of Tidal Fronts with Its Microscale Structure Evolution (해양전선 : 조석전선의 형성 및 그 미세구조의 전개 과정)

  • Yi-Gn Noh
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • v.21 no.1
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    • pp.17-30
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    • 1993
  • The basic processes responsible for the generation of oceanic fronts were reviewed. In particular the process of a shelf sea front produced by tidal stirring was identified from the one dimensional model of the water column in the coastal area, which incorporates the microscale process for the formation of a tidal front. Also a new criterion to predict its location was suggested. The time evolutions of the distributions of density and turbulent kinetic energy calculated from the model show that the criterion for the formation of a thermocline can be predicted as $R{\delta}^4$~ constant for large $\delta$ ($\delta$>0.5), but the dependence on $\delta$ decreases as $\delta$ goes to O, where $R=H^4Q/{K_b}^3$,{\;}{\delta}=1-Do/H$, Q is the buoyancy flux at the surface, $K_b$ is the eddy diffusivity maintained at the bottom and Do is the depth of a thermocline in the absence of bottom mixing. The depth of a thermocline was found to decrease as the bottom mixing increases for a given value of Do. The results were interpreted in comparison with the previous studies.

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Derivation and Comparison of Narrow and Broadband Algorithms for the Retrieval of Ocean Color Information from Multi-Spectral Camera on Kompsat-2 Satellite

  • Ahn, Yu-Hwan;Shanmugam, Palanisamy;Ryu, Joo-Hyung;Moon, Jeong-Eom
    • Korean Journal of Remote Sensing
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    • v.21 no.3
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    • pp.173-188
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    • 2005
  • The present study aims to derive and compare narrow and broad bandwidths of ocean color sensor’s algorithms for the study of monitoring highly dynamic coastal oceanic environmental parameters using high-resolution imagery acquired from Multi-spectral Camera (MSC) on KOMPSAT-2. These algorithms are derived based on a large data set of remote sensing reflectances ($R_{rs}$) generated by using numerical model that relates $b_b/(a + b_b)$ to $R_{rs}$ as functions of inherent optical properties, such as absorption and backscattering coefficients of six water components including water, phytoplankton (chl), dissolved organic matter (DOM), suspended sediment (SS) concentration, heterotropic organism (he) and an unknown component, possibly represented by bubbles or other particulates unrelated to the first five components. The modeled $R_{rs}$ spectra appear to be consistent with in-situ spectra collected from Korean waters. As Kompsat-2 MSC has similar spectral characteristics with Landsat-5 Thematic Mapper (TM), the model generated $R_{rs}$ values at 2 ㎚ interval are converted to the equivalent remote sensing reflectances at MSC and TM bands. The empirical relationships between the spectral ratios of modeled $R_{rs}$ and chlorophyll concentrations are established in order to derive algorithms for both TM and MSC. Similarly, algorithms are obtained by relating a single band reflectance (band 2) to the suspended sediment concentrations. These algorithms derived by taking into account the narrow and broad spectral bandwidths are compared and assessed. Findings suggest that there was less difference between the broad and narrow band relationships, and the determination coefficient $(r^2)$ for log-transformed data [ N = 500] was interestingly found to be $(r^2)$ = 0.90 for both TM and MSC. Similarly, the determination coefficient for log-transformed data [ N = 500] was 0.93 and 0.92 for TM and MSC respectively. The algorithms presented here are expected to make significant contribution to the enhanced understanding of coastal oceanic environmental parameters using Multi-spectral Camera.

Tracking of Yellowtail Seriola quinqueradiata Migration Using Pop-up Satellite Archival Tag (PSAT) and Oceanic Environments Data (위성전자표지와 해양환경자료를 이용한 방어(Seriola quinqueradiata) 이동경로 추적 연구)

  • Kim, Changsin;Yang, Jigwan;Kang, Sujin;Lee, Seung-Jong;Kang, Sukyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.5
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    • pp.787-797
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    • 2021
  • Yellowtail Seriola quinqueradiata tagged with a Pop-up Satellite Archival Tag (PSAT) was released off the coast of near the Moseulpo, Jeju Island and the ecological data during about 40 days was obtained. However, it is difficult to determine the spatial location of underwater ecological data. To improve the accuracy of estimating the Yellowtail migration route using temperature, suitable background field of the oceanic environment data was evaluated and used for input data. After developing of the tracking algorithm for migration route estimation, three experiment cases were estimated with ecological data among the surface layer, the mixed layer, and the whole water column. All tracking experiments move from western to eastern Jeju Island. Additionally, tracking experiment using 3D ocean numerical model reveal that it is possible to estimate the migration route using the fish ecological data of the entire water column. Therefore, using a large number of ecological data and a high-accuracy ocean numerical model to estimate the migration route seems to be a way to increase the accuracy of the tracking experiment. Moreover, the tracking algorithm of this study can be applied to small pelagic fishery using small archival electronic tags to track the migration route.