• Korean Journal of Remote Sensing
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• v.27 no.6
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• pp.753-760
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• 2011

The satellite Chollian was successfully launched on June 27, 2010 and is expected to perform its communication, oceanographic, and meteorological duties for seven years. The follow-up launch of the Chollian satellite is already being planned, and diverse studies are under way to enable the use of the Korean satellite data. Studies are also being actively conducted in and out of Korea to visualize the meteorological data on the open-source virtual globes. The meteorological data include ground observation, satellite, and digital-model data. In this study, an efficient three-dimensional technique was developed to visualize typhoons on the virtual globes using the Chollian satellite data. This study was conducted to provide service to the public via the scientific visualization of the satellite image data, and to create an efficient satellite image analysis environment for meteorological researchers.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.1003-1010
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• 2013

In this paper, TCP/IP based Machine-to-Machine (M2M) communication uses CDMA/GSM network for data communication. This communication method is widely used by offshore moored buoy for data transmission back to the system server. Due to weather and signal coverage, the TCP/IP M2M communication often experiences transmission failure and causing data losses in the server. Data losses are undesired especially for meteorological and oceanographic analysis. This paper discusses a software approach to minimize M2M data losses by handling transmission failure and re-attempt which meant to transmit the data for recovery. This implementation was tested for its performance on a meteorological buoy placed offshore.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.1
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• pp.1-11
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• 1994

A curvilinear hydrodynamic three-dimensional model is presented for the study of wind-driven circulation in a shallow lake. Numerical results are compared with field data. Thermal stratification effects were found to be critical to the successful simulation of circulation under increasing winds. When there ate insufficient meteorological data, the so-called inverse method can be used for the estimation of heat flux.

• Ocean and Polar Research
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• v.34 no.2
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• pp.229-237
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• 2012

Using results from an Earth System model, we investigated change in primary production in the East China Sea, under a global warming scenario. As global warming progresses, the vertical stratification of water becomes stronger, and nutrient supply from the lower part to the upper part is reduced. Consequently, so is the primary production. In addition to the warming trend, there is strong decadal to interdecadal scale variability, and it takes a few decades before the warming trend surpasses natural variability. Thus, it would be very hard to investigate the global warming trend using data of several years' length.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.230-232
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• 2019

There is an accelerating need for ocean sensing where autonomous vehicles can play a key role in assisting engineers, researcher and scientists with environmental monitoring and collecting oceanographic data. This paper is performed to develops an autonomous sailing drone to be used as a sensor carrying platform for autonomous data acquisition at Sea. From a sailing drone design viewpoint, it is important to establish reliable prediction methods for sailing drone's resistance. The required power for the propulsion unit depends on the ship resistance and speed. There are three solutions for the prediction of ship resistance as follow analytical methods, model tests in tanks and Computational Fluid Dynamics (CFD). The present paper aims at simulating sailing drone friction resistance using numerical method. The dynamic mesh motion is used to describe the sailing drone movement.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.583-593
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• 1994

The East Korean Warm Current is known as an anticyclonic circulation in the Ulreung Basin in the southwestern East Sea of Korea. This circulation was approximately estimated by dynamic methods based on the oceanographic observation and remote sensing data. In this study, the existence of circulation in the anticyclonic region of East Korean Warm Current(Tsushima current) in early summer was directly measured by drogue tracking using a global positioning system. At the same time, the velocity was calculated by dynamic method and compared using data collected by remote sensing. As results, these values are shown to be nearly the same, and an anticyclonic circulation was found around Ulreungdo-Tokto. The maximum northward and southward flow speed was deduced to be around 0.6 and one knot, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.587-601
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• 2020

The ocean circulation was simulated in the East Sea and Ulleungdo-Dokdo region using ROMS (Regional Ocean Modeling System) model. By adopting the East Sea 3 km model and the HYCOM 9 km data, Ulleungdo 1 km model and Ulleungdo-Dokdo 300 m model were constructed with one-way grid nesting method. During the model development, a correction method was proposed for the distortion of the open boundary data which may be caused by the bathymetry data difference between the mother and child models and the interpolation/extrapolation method. Using this model, a super-high resolution ocean circulation with a horizontal resolution of 300 m near the Ulleungdo and Dokdo region was simulated for year 2018. In spite of applying the same conditions except for the initial and boundary data, the numerical models result indicated significantly different characteristics in the study area. Therefore, these results were compared and verified by using the surface current data estimated by satellites altimeter data and temperature data from NIFS (National Institute of Fisheries Science). They suggest that in general, the improvement of the one-way grid nesting with the HYCOM data on RMSE, Mean Bias, Pattern correlation and Vector correlation is greater in 300 m model than in the 1 km model. However, the nesting results of using East Sea 3 km model showed that simulations of the 1 km model were better than 300 m model. The models better resolved distinct ridge/trough structures of isotherms in the vertical sections of water temperature when using the higher horizontal resolution. Furthermore, Karman vortex street was simulated in Ulleungdo-Dokdo 300 m model due to the terrain effect of th islands that was not shown in the Ulleungdo 1 km model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.2
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• pp.151-166
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• 1990

Using the data observed on the Oshoro-maru from November 4 to November 12, 1989 in the East China Sea, the oceanographic conditions were investigated. The results are as follows: The oceanographic condition of surface layer was divided into two regions. One was the Tsushima Current Waters and the other was the China Coastal Waters. The oceanic front was formed between above two waters. Tsushima Current Waters had high temperature ranging 22~24$^{\circ}C$, high salinity ranging 33.5~34.5$\textperthousand$ and low D.O less than 4.5ml/l. And China Coastal Waters had low temperature ranging 18~2$0^{\circ}C$, low salinity less than 23.0$\textperthousand$ and high D.O ranging 4.0~5.0ml/l. In the case of the bottom layer, Tsushima Current Waters and China Coastal Waters appeared the same as the surface layer. In addition, the Yellow Sea Bottom Cold Waters and the Southern Bottom Waters of East China Sea distributed together with two surface waters above. The was temperature ranging 15~19$^{\circ}C$, salinity 34.5$\textperthousand$ and low D.O ranging 2.0~3.5ml/l and that was temperature less than 1$0^{\circ}C$, salinity less than 33.3$\textperthousand$ and high D,O greater than 4.5ml/l. The waters of intermediate characteristics between China Coastal Waters and Tsushima Current Waters seem to be resulted from the mixing occurred between the above tow waters, and it had temperature of 20.5~22.$0^{\circ}C$, salinity of 32.3~33.3$\textperthousand$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.83-90
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• 1984

The secular fluctuations of catches and fishing grounds of mackerals and the oceanographic conditions for the fishing grounds are examined by using the data of catches of mackerals by middle and large class purse-seiner during 1951 to 1981 and those of oceanographic observation carried out by Japan Meteorological Agency. The results are as follows; The fishing grounds of mackerals are respectively distributed at northeastern and southwestern areas from the central part of the East China Sea through every season of the studied years: 1968, 1974 and 1980. The narrow belt type of fishing grounds were formed inside of the Kuroshio in spring and winter of the three years. In summer mackeral species move northward and the fishing grounds are formed in the southern sea of Korea. In winter, however, mackeral species move southward and the fishing grounds are appeared in the Tsushima Current region. The dispersion of fishing grounds is generally larger in summer and smaller in spring, and especially it is the largest in summer in 1980. It seems that the concentration and dispersion of fishing grounds are related to the depth of thermocline and the position of horizontal temperature gradient in this area.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.1-12
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• 2023

Oceanic wind waves have been recognized as one of the important indicators of global warming and climate change. It is necessary to study the spatial and temporal variability of significant wave height (SWH) and wave direction in the Yellow Sea and a part of the East China Sea, which is directly affected by the East Asian monsoon and climate change. In this study, the spatial and temporal variability including seasonal and interannual variability of SWH and wave direction in the Yellow Sea and East China Sea were analyzed using European Center for Medium-Range Weather Forecasts (ECMWF) Reanalysis 5 (ERA5) data. Prior to analyzing the variability of SWH and wave direction using the model reanalysis, the accuracy was verified through comparison with SWH and wave direction measurements from Ieodo Ocean Science Station (I-ORS). The mean SWH ranged from 0.3 to 1.6 m, and was higher in the south than in the north and higher in the center of the Yellow Sea than in the coast. The standard deviation of the SWH also showed a pattern similar to the mean. In the Yellow Sea, SWH and wave direction showed clear seasonal variability. SWH was generally highest in winter and lowest in late spring or early summer. Due to the influence of the monsoon, the wave direction propagated mainly to the south in winter and to the north in summer. The seasonal variability of SWH showed predominant interannual variability with strong variability of annual amplitudes due to the influence of typhoons in summer.